SWLing Post reader, Dr. Phil, recently contacted me regarding a collection of articles he’s written about DXing and radio modifications.

His site actually has a number of useful articles that I’ll plan to convert to future posts, with his permission.

I asked Dr. Phil for links to two of his most popular publications. He replied:

My two big recent articles are shown below. One is about “Pocket Radio DX”: using under-$20 radios to DX (started in 2003). Click here to download as a PDF.

The other is about using an $18 NooElec TV-tuner as a MW and shortwave receiver. Click here to download as a PDF.

Brilliant! Thanks so much for sharing these, Dr. Phil!

I actually have a  Sony ICF-S10MK2, which I consider to be a capable and useful little AM/FM receiver for the sub $20 price. I’ve also been very tempted to purchase an RTL-SDR dongle, so I may go ahead and bite the bullet on one of the NooElec SDR dongles.

In June, I made a small leap of faith and purchased a (dead) Sony ICF-SW100 from Universal Radio (see the listing on right).

You see, for many years, I’ve dreamed about owning this wee little receiver, now a classic among tiny radios, but used ones are typically too expensive for my modest budget.

This time, seeing the ad at Universal, I spoke with Universal Radio directly to obtain more details about their defunct unit; while they simply didn’t know what was wrong with the Sony, they were able to very accurately describe its cosmetic and functional condition…I took a deep breath, and decided to take a chance on it anyhow.

In full disclosure, I have a secret weapon in my camp:  my talented friend, Vlado (N3CZ), who is not only the most adept electronics engineer/technician I’ve ever known, but one who truly welcomes a challenge.  The thought had occurred to me as I admired the wounded Sony, Wonder if Vlad would like to take this on–?

The answer, of course, was Yes!  So I dropped the DOA Sony off at Vlad’s home last week. He disassembled the radio, only to discover that my ICF-SW100 was a victim of the (dreaded) damaged ribbon cable.

A short history of the Sony ICF-SW100 and SW100S

These radios are indeed brilliant, incredible performers for their miniscule size.  Yet the first generation of ICF-SW100 radios–those produced before the fall of 1997–have a design weakness: the ribbon cables which connect the upper and lower portions of the radio’s clamshell design eventually fail. Multiple openings and closings bend and cut the cables, rendering the otherwise remarkable little radio useless.

SWLing Post contributor, Dan Robinson, recently shared his knowledge about the ICF-SW100 series. Dan notes:

SW-100 Seekers Beware

As shortwave veterans know, the classic SONY miniportables — SW-1, SW-100(S) and  SW-07, represented some amazing technological achievements. SONY managed to  shrink some fantastic technology into these receivers, including (with the last two in the line) — SYNC capability. The SW-07, which was the last of these receivers, still brings some high prices on Ebay.

But if you are searching for the ICF-SW-100S there are some things to consider and beware of. As everyone knows, the SW-100 suffered from the well-known ribbon-cable failure problem. SONY addressed this problem in later serial numbers, and changed the design of the radio case.

Modified SW-100s have a notch where the top cover meets the base.

There are some dishonest sellers out there who are trying to pass off older version SW-100s as modified ones. Usually, the tip-off is that the photograph in the Ebay auction will be dark or out of focus, so it’s hard to tell if the radio is the modified version or not.

It has become quite rare to find an original SONY modification kit, which includes a new top cabinet of the SW-100. And some sellers are trying to get as much as $300 for these, though they rarely sell at this level.

ICF-SW100 modification kit found on eBay at time of posting.

It’s also becoming rare to see SW-100S radios new-in-box. I had two of these, sold one and kept the other.

If you’re after one of these marvel radios, do what everyone should do when considering items on Ebay — ask many questions about [the] cosmetic condition, accessories, serial numbers, etc.

Universal Radio, a trustworthy seller I know, had fully disclosed the model number and problems with this radio, so I knew exactly what I was buying. Dan has a very good point, though: unless you know the seller to be honest, do your research and ask questions!

The ailing ICF-SW100

Vlado discovers the faulty ribbon cable (click to enlarge)

Back to my ailing unit:  Vlado delivered the news about the ribbon cable via text message, and though I was well aware that the chances were high that was the ribbon cable, I was a little bummed, to say the least, to get the formal diagnosis.

Why? As Dan mentions above, you’ll find that the SW-100S upgrade kit Sony produced in the 1990s is no longer available new; sellers typically list these kits at prices in excess of $300 US.  Out of my budget.

But Vlado, ever the intrepid engineer, had no idea I would be disappointed with this news; he was just giving me this FYI via text. Indeed, he seemed entirely unfazed, as in, hey, no serious internal damage here…

Another hour passed. Then came another message from Vlad; this one simply said: “Call me.”

Oh no, I thought. But I called, and Vlado answered cheerfully, “Hello? Tom, is that you? Sorry, I can’t hear you very well because your SW100 is playing too loudly. Hang on–let me turn the volume down!”

Vlad installs the replacement ribbon cable (click to enlarge)

“What!?!” I responded, in utter disbelief.

Yes, he’d got it working!  It seems that Vlad had unearthed an old DVD player in his garage that he’d kept merely for parts. He opened it up, identified a ribbon cable with the right pitch, then cut and folded the cable to fit into the SW100.  Ingenious!

That’s Vlado for you!

And should I be interested in replacing this used cable with a new one–or in repairing other Sonys–Vlad directed me to eBay listings for new cables which only total about $20, shipped. Truthfully, I’m in no hurry, as this one is functioning perfectly and changing out the ribbon cable seems to have no effect on stored memories, etc. With a single affordable eBay purchase of multiple cable sets, it occurred to me that Vlad would have enough replacement cables to repair the SW100 many times over…

So I bought the cables.  (This one for the narrow cable and this one for the wider one.)

My “new” Sony ICF-SW100

Needless to say, I’m very pleased with my “new” (to me) SW100. It’s a little masterpiece of receiver engineering in such a tiny package.  And since the ICF-SW100 is unquestionably the smallest portable I own–and is one of the few I own with a proper line-out jack–it may very well become my go-to radio for one bag travel.

It’s in the bag: listening to the ‘SW100 before I pack it for my next trip!

Stay tuned the review…

Vlado’s radio E.R.:  the doctor is in

As I’ve said, Vlad is one of the most adept repair technicians I’ve ever known.  At my prompting, he’s kindly agreed to let me promote his services here on the SWLing Post. Vlad acknowledges that he “likes a challenge,” adding that he enjoys nothing more than making repairs even when”parts are scarce” and radio”surgery” is required.  Moreover, his bench fees will be quite reasonable, especially considering what you receive: new life for a failing radio. So, if you’ve got an ailing rig on your hands, and don’t mind waiting for Vlad to get to it, send it to his radio emergency room, where radios (like my Sony) have life breathed back into them once again.

Long live the Sony ICF-SW100!  And long live Dr. Vlado, who makes this possible with his creative (and nearly miraculous) repairs.

To contact Vlad, simply contact me with a description of your radio and its problem and I’ll put you in touch with Vlado.

Many thanks to SWLing Post contributor, Moshe, who writes:

About 2 weeks ago, a very good friend called me and exclaimed, “you just have to see this radio…I’m keeping it for you!”–so, I drove to his aunt’s house and saw this beauty.

After hauling the radio to my place, I started to check it out, to see what would be needed for restoration; it was working, with bad contacts, poor frequency response and low output.

I took hi-res pictures of this radio, some during restoration. Now the radio sounds great. It has been recapped, a couple of bad resistors and bad wires replaced, contacts have been cleaned, and some good cleaning for the chassis as well.

As I wanted to keep the original appearance of the chassis, I kept the original filter capacitors on board, but disconnected them from the circuit, added terminal strips and new capacitors from underneath.

The radio uses an EF85 tube as the RF stage. With the addition of a grounding connection and random wire antenna, it’s very sensitive on shortwave.

About the Ben-Gal Duet-Stereo:

It was made in Israel by Ben-Gal, a label inside shows it was made at 12th of December, 1965.

It is a console model with record player. As the model name suggests, the amplifier and record player are stereo (though the tuner is not…).

The radio has longwave (marked in meters), mediumwave (marked in meters) and 3 shortwave bands (with megacycle and meter band marks).

The shortwave bands overlaps with each other, so cover is continuous:

• SW3 2.3MHz to 6MHz,
• SW2 5.5MHz to 15.5MHz,
• and SW1 14.5MHz to 23MHz.

Many thanks, Moshe, for sharing photos and this description of this beautiful Ben-Gal Duet-Stereo. I bet the audio fidelity is amazing. My father has a 1960’s console–with a similar configuration–made by Admiral, though it was limited to mediumwave and FM reception. Some day, I will try to restore it to its former glory!

Thanks for the inspiration, Moshe!

My Powermate USB sporting a white rubber band grip.

After publishing the post about my PowerMate USB controller, Mike Ladd replied on Facebook:

“Do what I did a couple of years ago and add a lobster claw rubber band to the [PowerMate] tuning wheel.”

In case you’re not familiar, Mike is referring to the thick, wide rubber bands that are placed on lobster claws to hold them shut. Mike included the following video; you can see that the rubber band fits perfectly around the top of the tuning knob, giving it a little extra grip.

This same type of rubber band can often be found in the produce department of grocery stores as it’s used to hold bunches of broccoli, asparagus and other produce together.

Many thanks for the tip, Mike!

Many thanks to SWLing Post reader, Stan (WA1LOU), who writes:

“Enjoy your blog. I have been reading it for years. [H]ere is something your readers might be interested in that I mentioned in my blog today:

http://www.horzepa.com/2015/09/computer-controlled-switch-system.html

Very cool! Goes to show that there are a countless number of applications for the Arduino system to be used with amateur and shortwave radio.

Click here to read Stan’s informative post, and here to order the TASS system from TAPR.

John Ackermann also produced this informative presentation/video about the system:

In reference to our previous posts about the Sony SRF-59 ultralight receiver, SWLing Post reader, Bill Mead, writes:

“As someone who doesn’t normally open the backs of radios, this is my mod on my ultralight. All it takes is a bit of electrical tape to hold the belt clip on the loop.”

That is, indeed, a brilliant and simple mod. The SRF-59 inductively couples to the loop antenna, so no soldering is needed; simply tape the belt clip to the loop, making sure the position is convenient for tuning the SRF-59 and the loop’s capacitor.

You can find passive loop antennas ranging from $19 to $50 US. The Grundig AN-200 and the Terk AM Advantage are two models currently on the market. Here are a few places you can check prices:

Grundig AN-200:

• Universal Radio ($19.99 at time of posting!)
• Amazon.com (who also sells the same antenna branded as the Kaito AN-200)
• eBay.com

Terk AM Advantage:

• C.Crane
• Universal Radio
• Amazon.com
• eBay.com

Many thanks to SWLing Post contributor, James Patterson, who writes:

Has anyone ever thought of changing the Tuning knob on the PL-660?

Putting a larger knob on it makes for much easier turning instead of the very small fiddly knob Tecsun supply.

Finding the right plastic knob maybe a problem, needing to insert it over the tuner cam. But modifying another knob off something else is what I did.

Tricks of the trade!!

That looks like a very simple and effective mod, making the 660 more tuner-friendly for you! Thank you for sharing, James!

Many thanks to SWLing Post contributor, Jeff McMahon (at the Herculodge), who writes:

I upgraded my Sangean U3 with a male to female iMBAPrice 6 foot stereo audio extension cable 3.5mm, which I plugged into the U3’s auxiliary port.

The U3’s small stub of an FM antenna really needed some extra oomph. Now my U3 is picking up all my favorite stations, including the problematic KPCC 89.3 in Pasadena.

AM is as great as always. The sound is crystal clear on AM and FM. If this radio weren’t so big, I’d buy two more for the kitchen and my bedroom, but will have to be content to have one for my gym/office radio.

Thanks, Jeff! I might have to consider the Sangean U3–I hope a reader will let me know if one goes on sale.

Like Jeff, having a radio that not only performs admirably, but that can also withstand the attention of my kids, may be a great investment over the long-term! I’m glad such a simple addition to the U3 means that you can now hear your favorite Fm station, Jeff!

Now if Sangean only made a shortwave version of the U3–!

Friday, I brought home an untested, slightly grimy, Sony ICF-5500W. I purchased it through Goodwill for $20.

I crossed my fingers as I put three C cells in the radio and turned it on. Fortunately, I was rewarded with brilliant audio. I tuned the ‘5500W on AM/mediumwave and heard CFZM,  500 miles to my north, and Radio Reloj, 860 miles to my south. A quick scan on the FM dial revealed that I could also hear all of my local benchmarks. Whew!

Other than the dial needing a little calibration, and DeOxit on a few pots, it’s in excellent mechanical shape.

I started cleaning the radio last night using Q-tip cotton swabs and a vinegar/water solution.

I’d like to restore the hard plastic chassis’ original shine, though.

I was tempted to reach for some Armor All, but stopped myself short. I know it would give the ICF-5500W a nice shine, but would it cause any long-term damage to the black plastic or clear dial cover?

I know there are vintage radio restorers among the SWLing Post readership. Can someone offer advice on what’s the best product to use (or not use!) on my ICF-5500W?

If you have experience, please comment!

In this post, I will show you how to use an SDR as a panadapter for a commercial communications receiver. I’m using an Icom R72 and a SDRPlay RSP, but you can do it with nearly all receivers and SDRs.

The Icom R72 is a double conversion HF (0-30 MHz) communications receiver.

A panadapter lets you see the spectrum of your receiver (it gives you a broader, higher-level picture of what’s around your tuned frequency). After using it, you’ll wonder how you’ve been using your receiver without a spectrum display!

Almost all the radios we use are of superhetrodyne type. To connect a SDR to the radio, you should first find its 1st IF mixer output (if it has more than one Intermediate Frequency stage).

To find it, the best way is to consult the service manual. The first IF of Icom R72 is 70.4500 MHz, so we can use RTL-SDR dongles too.

Here’s a part of R72’s schematics, extracted from its service manual:

Look at the R82 resistor; it’s located at the output of first IF stage, so I soldered a connector to its pins (its other pin is connected to the ground)

Between the R82 resistor and the output, we’ve added a series 470-ohm resistor (to prevent loading the IF stage)

Click to enlarge.

The other side of this connector is connected to the antenna input of my SDRPlay RSP.

Now I can view my spectrum on a PC.

Here’s a screenshot of CubicSDR on Mac OS X (you can use other apps like HDSDR, SDR Console, etc.):

Although this post was about the SDRPlay RSP and Icom R72, this procedure can be done for almost any combination of receivers and SDRs provided that your SDR covers the frequency of first IF stage.

Also, don’t forget that you should tune the SDR to the frequency of IF–in this case: 70.4500 MHz.

Mehdi Asgari, the author of this post, is a regular contributor to the SWLing Post. Mehdi lives in Tehran and is an active member of the EP2C amateur radio club.

In this post I’m going to tell you how I repaired my Icom IC-R72 receiver. Although it’s about a specific device, the logic and methodology applies to all radios.

I bought an Icom R72 from a friend for about $200. At first, I just checked 7.0MHZ (40 meter band) and 21.0MHZ (15 meter band) and it was OK. After some time, I tried to listen to some ham radio on 20 meters (14.0MHZ) and it was deaf! I checked everything: antenna connectors, balun…everything.

With some trial and error, I found out that it was deaf from 11-15 MHz. With the help of the members of “Icom R72” Yahoo Group, I found one of the usual suspects: bandpass filters’ switching diodes.

I took a look at the service manual and apparently this radio uses multiple bandpass filters  for different  frequency ranges.

As you see in the above picture (grabbed from service manual), one of the bandpass filters is for 11-15 MHz range–that’s the range where my radio was deaf.

Note that there are multiple ways to test that a radio is deaf at a frequency. One of the simplest ways: connect an antenna or even a long wire to the antenna socket of radio. The noise level should increase; if not, there’s a problem.

After testing diodes with a multimeter, I found out that D31 is faulty. Almost all multimeters have a diode-test functionality.

I replaced it. The original diode was 1SS53, but I used a 1N4148 which is very common and found everywhere. Now I have a working radio!

If you have a radio that’s deaf at a frequency range, there is probably a problem in bandpass filters.

Here are some internal pictures of my Icom IC-R72:

I should thank my friend and electronics mentor, Saeed (EP2LSH) who always helps me in my electronics adventures.

Mehdi Asgari, the author of this post, is a regular contributor to the SWLing Post. Mehdi lives in Tehran and is an active member of the EP2C amateur radio club.

Many thanks to SWLing Post contributor, James Patterson, who writes:

I have owned the Sony ICF-SW55 for around 15 years or more. I like to change my listening pleasure from radio to radio, giving each one a rest, as they are all different to a degree. So I put the SW55 away and it sat unused for about six moths, as with my radio collection, I had others to listen to.

But when I decided to listen to the SW55 again, it just wouldn’t power up at all. I have read posts from other listeners saying their radios won’t power up either after sitting for extra long periods. I think they are mostly Sonys.

I tried many times but no it wouldn’t power up; I decided I’d just keep it as a memory of a failed Sony radio. I’m aware that the capacitors do blow, and assumed that’s most likely the problem.

But I decided there may be another way to get it going again. I always check for [battery compartment] corrosion, but there was none.

I thought of a crazy idea of actually freezing the radio–just to see what may happen. So it was in the chest freezer for 3 hours. I then took it out frozen like an ice brick!!.

I took it outside to the blazing hot sun and let it fully defrost. I then plugged a DC power pack into it. The operating voltage is 6 volts. I pushed 9 volts into it, through the switchable power pack. I got a plastic clamp and clamped the on/off switch permanently “on”.  I could hear it turning on and off several times as the switch is electrically-activated.

Then all of a sudden it sprang to life–unbelievable! On it came at full volume, so I selected an AM station and it worked as good as it ever did. The sensitivity was always very good, and it still is.

So was it a “Fluke”, “freak of nature” just by chance, or was it the freezing that woke it up?

Well I’m not turning it off. I have new AA batteries in it, as well as the power pack that’s turned back to the correct 6 volts–and yes it’s still going!!

So maybe we should all start freezing our radios when they have given up the “ghost”!?! Don’t forget to defrost before powering up!! Maybe I’ve started a “new trend”. Any comments would be great! Thanks.

Thanks Thomas and have a great and happy New Year from New Zealand.

Wow–James, I’m not sure why this freezing method worked, but I’m glad it did!

I don’t think I could recommend that everyone try this but, James, you did this out of desperation since you essentially had a nice ICF-SW55 paperweight. What did you have to lose? I’m very curious if some engineers or electronics technicians could comment as to why freezing the radio helped.

I do know this: I would be cautious attempting James’ freezing method if you live in a humid environment. It’s possible that the condensation from the radio thawing could actually cause moisture damage. Obviously, in James’ case, it did not.

Thanks again, James–I hope your ICF-SW55 gives you many, many more years of service!

If you own a Tecsun PL-360, PL-365 or a CountyComm GP5/DSP or GP5/SSB, you might take note of this large ferrite bar antenna offered by a Greece-based seller on eBay.

As you can see in the image above, this antenna is substantially larger than the stock MW antenna supplied by the manufacturer. According to the seller, this ferrite bar antenna has a 10 – 25 db gain over the stock external antenna. I imagine its ability to null unwanted signals is also much better.

The price is about $40 US shipped internationally.

Have any SWLing Post readers ordered this antenna? If so, please share your comments/reviews.

Click here to view the antenna on eBay.

SWLing Post reader, David Korchin, also shares the following demo video on YouTube:

Many thanks to SWLing Post readers, Francis Frankenne and David Korchin for the tip!

SWLing Post contributor, Gary DeBock, is an acclaimed innovator in the realm of Ultralight DXing–he’s well-known for constantly pushing the envelop on these inexpensive DX receivers.

This time, Gary has published a detailed home-brew project that can turn your stock Tecsun PL-380 into a Mediumwave DX Fiend!

In Gary’s own words:

This is the “Science Fiction PL-380” model, with the hobby’s first hard-wired FSL antenna in a portable configuration. The radio’s internal Si4734 DSP chip tunes the high sensitivity MW antenna, so there is no need to peak a variable capacitor. For those who can build or obtain this model, it will be a happy new year indeed!

Many thanks to Gary for the following guest post:

3 Inch FSL Tecsun PL-380 Model

Compact Breakthrough in MW Sensitivity, Selectivity and Portability

By Gary DeBock, Puyallup, WA, USA
January 2016

Introduction  

Portable radio enthusiasts were astonished when Silicon Labs first introduced their innovative Si4734 DSP chip in 2009—the pocket radios empowered by this new component had amazing DSP-enhanced selectivity. Although the relatively lame stock loopsticks designed by the Kchibo and Tecsun companies seriously limited MW sensitivity there was no shortage of fanatical hobbyists designing upgrade loopsticks in an effort to correct this deficiency. The 7.5” loopstick transplant boosted the MW sensitivity of the PL-380 model up to a much improved level, and it became the most popular modification in our Ultralight radio group.  But in 2011 another huge breakthrough was about to capture the fascination of our DXing niche group—Graham Maynard published his original Ferrite Sleeve article, and the innovative antenna’s sensitivity made our humble pockets radios perform like real transoceanic DXing contenders. This was very thrilling—but was there any possible way that the awesome selectivity from the Si4734 DSP chip and the awesome sensitivity provided by the FSL antenna could somehow be combined in a self-contained breakthrough portable, with lightweight portability as an added bonus?

The fact that an Si4734 DSP chip could successfully tune an external antenna was demonstrated by various experimenters (including me) in 2011—a hard-wired 3” Longwave FSL design worked quite well for me in early 2011, and although it was far too heavy to consider attachment to the PL-380 the validity of the hard-wired FSL concept was proven to my satisfaction (see photo at right). The challenge has always been to create a hard-wired FSL that would offer both high MW sensitivity and lightweight portability— a value tradeoff that made this project especially intriguing.

After testing various designs I finally settled on a 3” FSL composed of the lightweight Russian surplus 100mm x 20mm x 3mm ferrite bars. These bars provide a unique balance of high sensitivity and lightweight portability, and the cylindrical shape of the FSL apparently provides the fringe benefit of exceptional nulling capability. The PL-380’s Si4734 chip easily tunes the antenna for breakthrough MW sensitivity from 521-1701 kHz, and provides excellent 1 kHz DSP selectivity as well. The weight of the FSL-enhanced PL-380 is within reason to maintain the concept of easy portability, and its modest size may actually convince airport security agents that it is indeed a radio and antenna combination. Overall the project has been a very satisfying effort to combine the awesome capabilities of both the Si4734 DSP chip and the new FSL antenna– resulting in a breakthrough “travel portable” with astonishing MW-DXing performance.

Project Overview  

This modification procedure will convert the Tecsun PL-380 AM-LW-FM-SW portable from a modest-performing Medium Wave receiver into an exceptional one, with a significant enhancement of Longwave performance as well. The process involves some close-order soldering on a crowded PL-380 circuit board, and should only be attempted by those will good close up eyesight, steady hand coordination and some soldering experience. Certain component parts (such as the 100mm x 20mm x 3mm ferrite bars, the 2.25” Funnoodle inner cores and the orange plastic antenna frames) may be in short supply depending upon current demand, and it is recommended that all these collected prior to starting the project.

Since major portions of this project involve duplication of procedures contained in the PL-380 7.5” Loopstick Transplant article, reference is made to various steps and instructions in that article (posted at

http://www.mediafire.com/view/du3sr5cd9thqvau/7.5inch-LS-PL380.doc ). As such, hobbyists who have successfully completed the 7.5” loopstick transplant project on a PL-380 will find this procedure relatively simple, with only the 3” Bar FSL construction as a new challenge. The resulting FSL-enhanced PL-380 truly provides a quantum leap in MW-DXing performance over the stock model, but reasonable care is necessary to protect the modified portable from sudden drops or mechanical shocks. Completion of the finished radio should provide a great level of satisfaction and hobby enjoyment, especially during travel opportunities where external antennas are impractical or forbidden.

Construction Parts Required

A) Tecsun PL-380 AM-LW-FM-SW Receiver (available from many sources, including this eBay listing at $46.99 with free shipping to the USA)  http://www.ebay.com/itm/Tecsun-PL380-DSP-AM-FM-Shortwave-LW-PLL-Radio-Receiver-PL-380-/251783558999?hash=item3a9f783757:g:t0EAAOxylpNTTan7

B) 37 feet of 250/46 Litz wire  http://www.ebay.com/itm/Litz-wire-250-46-0-04-mm-for-crystal-radio-coil-Loop-antenna-100-/160804560511?hash=item2570b2de7f:m:m9fkDfLaAd59_UEmrp1po5w

C) 8 Russian surplus 100mm x 20mm x 3mm ferrite bars (availability currently uncertain– author has a limited supply. An eBay source may reappear for future orders, since many of these bars are presumably still in eastern Europe)

D) 4″ length of 2″ diameter Fun Noodle inner foam core

http://www.amazon.com/Aqua-World-223-Fun-Noodle/dp/B0017QABEQ/

E) Precut orange plastic antenna frame (cut from Ace hardware 48″ plastic level, with 5″ long bottom dimension and 4.5″ top dimension– cutting instructions to follow). NOTE: each Ace Hardware 48” level has enough material to make two FSL antenna frames.

F) Rite Aid 1″ wide waterproof tape (1 roll)

G) Scotch “Extreme” shipping tape (1 roll)

H) Tube of Duro Super Glue (or equivalent), .07 ounce

I) 6 inches of 1/16″ diameter shrink tubing

J) Two 18″ lengths of 125 lb. test plastic tie wraps

K) Two 16″ lengths of 75 lb. test plastic tie wraps

L) Oatey foam pack (4” wide)

M) Two 3/4″ x 1″ strips of 1″ I.D. rubber heater hose

Miscellaneous: Solder, 25w (low heat) soldering iron, hacksaw (or power miter saw), screwdriver set, sandpaper (optional)

PL-380 Preparation

Before voiding the warranty on your new PL-380, it’s a good idea to ensure that it has no existing problems which might require warranty service. (Ha!)

Install batteries in the radio and give it a test run on all four bands, checking the tuning encoder, clock, volume control, speaker, headphone jack, display functions and digital searching modes. Make sure that the radio is working properly in all functions before starting the modification procedure, since the eBay sellers are unlikely to show you any sympathy after you tear out the stock loopstick. It’s also a good idea to check out the Medium Wave weak signal reception with the PL-380 stock loopstick before starting the modification, to establish a benchmark of performance against which the new 3” FSL’s DXing performance will be compared.

STEP-BY-STEP CONSTRUCTION

1) Follow the detailed cutting procedures in steps 1-9 of the loopstick transplant article (using either a power miter saw or hacksaw) to prepare the FSL antenna mounting frame, HOWEVER please note that the top section length for this project is 4 ½” (114 mm), NOT 8” as in the loopstick transplant project. The finished precut frame should resemble the picture above, with the top section flat, and the bottom section back edge trimmed to allow full use of the radio’s whip antenna. The frame’s entire bottom section (including the glue surface) is identical in both the loopstick and FSL transplant projects.

2) Follow the detailed procedures in steps 17-22 of the loopstick transplant article to prepare the PL-380 cabinet for the FSL transplant procedure.

3) Refer to the photo above. Place the prepared PL-380 cabinet in the vertical position as shown, with a paper roll (or other item) to keep the cabinet in the vertical position. If necessary sand the edges (only) of the antenna frame’s glue surface to ensure that no cutting debris or rough edges will cause an uneven gluing surface. Use a clean, damp cloth or paper towel to remove all dust and debris from both the antenna frame and PL-380 glue surfaces, then wipe them thoroughly dry. Ensure that maximum light shines on the PL-380’s top glue surface (as shown in the photo below), then practice making multiple “dry runs” of placing the antenna frame directly centered on the PL-380’s front top cabinet surface, with its front edge lined up with the PL-380’s beveled front edge. You will only get one chance to place the frame accurately when the super glue is on the PL-380 surface, so make sure that you know exactly what to do! The antenna frame should sit completely flat against the PL-380 cabinet, and slide across it smoothly if such a test is made. If not, sand any rough edges on the antenna frame’s glue surface and repeat the cleaning procedure.<

4) Refer to the photo above. After ensuring that you are fully prepared for accurate placement of the antenna frame on the PL-380 cabinet, place a 4 1/2” x 3/16” bead of super glue (114 mm x 5 mm) on the PL-380’s front top cabinet surface, as shown in the photo. Refer to the photo on the top of the next page. Ensure that the front side of the antenna frame (as shown) is facing you, then place the antenna frame in a centered position flat against the PL-380 cabinet, with its front edge lining up with the front beveled edge of the cabinet, as shown in the photo. Press the antenna frame down firmly against the cabinet for about one minute, scraping away any excess glue from the front and back edges with a small, flat jeweler’s screwdriver. It is especially important to remove any excess glue from the back edge of the antenna frame in order to allow the PL-380’s back cabinet to close normally. After completion of this step place the PL-380 (with the attached antenna frame) in a secure area until the FSL antenna is constructed.

CONSTRUCTION OF FSL ANTENNA

5)   Refer to the photo above. Ensure that the end edges of the 4” Funnoodle inner foam core are perfectly straight before performing this step. Place the inner foam core flat on a table, standing on one of its edges as shown. Take the roll of 1” wide waterproof tape and wrap two turns tightly around the inner foam core as shown in the photo, with the adhesive side out. Ensure that the two turns are wound tight enough so that they will not slide up or down the inner foam core. Take the first 100mm ferrite bar and press it firmly against the waterproof tape with its short edge completely flat on the table, and long edges completely parallel to the edges of the inner foam core (as shown). It is important to place this first bar accurately, in order to start an accurate pattern for the set of 8 bars.

6)   Refer to the photo above. Press another of the 100mm ferrite bars against the waterproof tape in a position where it is perfectly flat on the table and perfectly parallel with the first bar, with 1/8” (3 mm) spacing between the bars. Continue to place the other 6 bars on the inner foam core in exactly the same way, ensuring that all 8 bars are flat against the table and parallel with each other, having 1/8” (3 mm) spacing between them. If necessary (after placing all 8 bars on the tape), even out the spacing by moving certain bars slightly so that the gaps between them are all equal. The set of 8 bars will be compressed in the next step to form an octagonal pattern.

7)  Refer to the photo above. Place a 75 lb. test plastic tie wrap around one edge of the set of 8 bars as shown, 1/2” (12 mm) from the ends of the bars. Slowly and carefully compress the set of 8 bars as shown, tightening up the slack in the plastic tie wrap gradually as you compress the set of bars. Continue this gradual process until the set of 8 bars forms an octagonal (stop sign) pattern, with the bars barely touching each other on their compressed edges.  At this point take up any remaining slack in the plastic tie wrap, and stop compressing the bars. Repeat this process on the other side of the ferrite bars with another 75 lb. test plastic tie wrap, ensuring that the bars form another octagonal pattern, with their compressed edges barely touching each other. Again take up the slack in the plastic tie wrap, and then use diagonal cutters to trim the excess ends of the plastic tie wraps.

8)   Refer to the photo above. Place the prepared set of 8 bars flat on the table on one of its ends, as shown. Take the roll of 1” waterproof tape and tightly wrap two turns of tape around the ferrite bars as shown, with the adhesive side out. Space these two wraps evenly as shown, ensuring that they are tight enough not to slide up and down the bars.

9)   Refer to the photo above. Take the Oatey 4” foam pack, remove the center staple and locate a 9” (23 cm) long length of this foam which is free of any holes or imperfections. At the beginning of this 9” (23 cm) long length of foam cut a perfectly straight line perpendicular to the edges of the foam. Press this straight edge of foam down tightly against the waterproof tape as shown, with the edges of the 4” Oatey form lining up with the edges of the bar assembly’s inner foam core. Wrap this Oatey foam tightly around the waterproof tape until the foam touches the plastic tie wrap clamps.

If necessary, re-wrap the foam tightly so that it is centered on the ferrite bar assembly.

10)   Refer to the photo above. Pull the Oatey foam wrap tightly around the bar assembly, then cut a straight edge to mate evenly with the previously cut straight edge. Before pressing this edge down on the tape cut side notches in the foam where the tie wraps clamps are located, as shown. The press this foam edge tightly down on the tape, mating evenly with the previously cut foam edge. Ensure that there are no gaps or overlaps in the foam edges; if necessary, pull the foam wrap once again all around the bar assembly and cut a new straight edge that will mate evenly, with no gaps or overlaps. Finally, secure this newly cut foam edge with a 2 1/2” (64 mm) strip of waterproof tape, as shown.

11)   Refer to the photo above. Support the edges of the prepared bar assembly so that it will be raised off of the table. Wrap two turns of the 1” waterproof tape tightly around the center of the prepared bar assembly, adhesive side out (as shown). When wrapping the second turn, ensure that the inner zigzag edge of the waterproof tape mates evenly with the inner zigzag edge of the first turn of tape, with no overlap or gap.

12)   Refer to the photo above. Take your reel of 250/46 Litz wire and measure off 16” (41 cm) of wire from the end. Press this exact point down on the waterproof tape 1/8” (3 mm) from the left edge of the waterproof tape, as shown in the photo. While pressing down this Litz wire point while the wire is in a position parallel to the waterproof tape (as shown) pick up the bar assembly with one hand and the Litz wire reel with the other hand, pulling the Litz wire tightly around the circumference of the bar assembly in a straight, parallel manner to begin the first Litz wire turn. Ensure that this first turn stays 1/8” (3 mm) away from the left edge of the waterproof tape all around the bar assembly, then start the second turn directly adjacent to the first turn, ensuring that no gaps or crossovers occur while winding the turns. Carefully continue this process until 36 total turns have been wound around the bar assembly, which should leave the Litz wire coil in a centered position, similar to the photo below.  NOTE: This coil is designed to provide an inductance of 350 uH.

13)   Refer to the photo above. After 36 turns have been wound on the bar assembly, ensure that there is still a 16” (41 cm) length of loose Litz wire leading up to the first coil turn. Then place a strip of Scotch “Extreme” tape along the length of the bar assembly, with the lower edge of the tape along the point where the first Litz wire turn begins (as shown), and with the tie wrap clamps in back of the assembly. Press the tape down firmly to lock the coil into place. In the same manner, turn the bar assembly over and place another strip of “Extreme” tape along the bar assembly, with the lower edge of the tape along the point where the last Litz wire turn ends (where the wire leaves the coil), avoiding the tie wrap clamps. There should be about 2” (51 mm) of space between the two “Extreme” tape strips, and both loose Litz wire ends should be parallel as they come off of the coil. Press the second “Extreme” tape strip down firmly to lock the coil into place. Finally, measure off another 16” (41 cm) of loose Litz wire from the coil, cutting the Litz wire at that point.

14)   Refer to the photo above. Cut a 4” (102 mm) length of the 1/16” shrink tubing, and then cut a very short piece off of the ends of the Litz wires to ensure that these ends have the smallest and smoothest possible profile to be run through the shrink tubing. Run one end of the Litz wires through the shrink tubing until about 3 inches of wire extend from the tubing. Carefully insert the other end of the Litz wire through the shrink tubing, and use the procedure (and photo) in Step 30 of the Loopstick Transplant article to run the second Litz wire through the shrink tubing, as shown. The related photo for that procedure is included below.

15)  Place the previously prepared PL-380 and antenna frame assembly flat on the table, with a protective cloth to keep the front panel display from damage.

Take the prepared FSL antenna assembly and place it in the position shown, with the Litz wire shrink tubing running along the back side of the antenna frame and the lower edge of the FSL assembly next to the top of the antenna frame. Place the two 3/4” x 1” strips of rubber heater hose in the two positions shown, in between the antenna frame and the FSL antenna and also in between the coil and the FSL edges, with the longer rubber strip dimensions parallel to the FSL edges. Start the two 175 lb. test plastic tie wraps in the positions shown (down the center of the rubber spacer strips), ensuring that the rubber spacer strips remain between the FSL assembly and the antenna frame, and that the spacer strips are centered at the very bottom of the FSL assembly. Also ensure that the Litz wires are in the position shown, with no pinching or binding between the FSL assembly and antenna frame. Slowly and carefully tighten the first plastic tie wrap while ensuring that the rubber spacer strip remains in the proper position. Tighten this plastic tie wrap only enough to securely hold the FSL assembly, and do not tighten it to the point where the ferrite bars’ octagonal pattern begins to distort. In a similar manner, carefully tighten the other plastic tie wrap while ensuring that the rubber spacer strip remains in the centered position, in between the antenna frame and FSL assembly. Once again, tighten this tie wrap only enough to securely hold the FSL assembly, and not to the point where the ferrite bars’ octagonal pattern begins to distort. When this process is complete the large plastic tie wraps’ clamps should be in the position shown, lined up with each other and in a position to support the radio/FSL combination when the model is laying down flat, on a table. Cut off the excess tie wrap lengths.

16)   Refer to the photo above. Temporarily place the Litz wires down along the radio’s circuit board in the position shown. Locate the detailed circuit board antenna connection points “AN1” and “AN2” in the close up photo at the top of the next page. After locating these two circuit board connection points (with the Litz wires running in the position shown in the photo at left) place one of the Litz wires over the “AN1” circuit board point, and the other Litz wire over the “AN2” circuit board point. Then measure out about 1” (25 mm) extra

Litz wire past these two circuit board connection points, and after making sure that the Litz  wires are still in the approximate position shown in the photo at the beginning of this step, cut one (shorter) Litz wire 1” (25 mm) past the “AN2” circuit board point, and one (longer) Litz wire 1” (25 mm) past the “AN1” circuit board point.

17) Refer to the photo below. Temporarily place the Litz wires outside of the radio as shown, and install a 1 1/2” (38 mm) long section of shrink tubing over both Litz wires, and a 1” (25 mm) long section of shrink tubing over the longer Litz wire. Position both sections of shrink tubing as shown in the photo below.  Place some type of protective material under the Litz wire so that the soldering procedure (in the next step) will not damage your work surface.

NOTE: The proper procedure of tinning the ends of the Litz wires requires that all of the individual Litz wire strands be soldered together at the ends. This requires a clean, shiny solder connection all around the circumference of the Litz wire ends for at least 1/8” (3 mm). When preparing the ends of the Litz wires in the next step, ensure that the ends are tinned in this manner before continuing.

18)   Refer to the photo above. Carefully tin the ends of both Litz wires in the manner described above, working around the circumference of the Litz wire ends with a clean soldering iron for at least 1/4” (6 mm). After doing this, cut off the tinned section on both ends to a length of 1/8” (3 mm). When viewing the ends of the Litz wires after tinning, the entire 1/8” (3 mm) length should be bright and shiny all around its circumference, as shown in the photo at the top of the next page. The cut surface of the Litz wire (the circular face) should also be bright and shiny, with one solid surface of melted solder.

19)   Refer to the photo above. Take the prepared ends of the Litz wires and route them as shown in the photo above, with the 1 1/2” (38 mm) section of shrink tubing placed in the cabinet clamp as shown, and the end of the 4” (102  mm) section of shrink tubing (coming from the FSL coil) also positioned as shown (where it will be run through the empty wrist strap hole, in the back cabinet side panel). Before placing the 1 1/2” (38 mm) long section of shrink tubing in the cabinet clamp refer to the picture at the top of the next page, and ensure that there will be sufficient slack in the 4” (102 mm) shrink tubing to be run from the FSL coil to the wrist strap hole (3/8” or 9 mm down from the top of the cabinet) without binding.

Ensure that the circuit board points “AN1” and “AN2” still have a small amount of melted solder on them (after removal of the PL-380 stock loopstick, as described in the Loopstick transplant article). Also ensure that there is no excessive length in either of the Litz wires, since these both must be positioned as shown (if necessary, cut one or both to the proper length, and re-tin them as described in the previous step). Place the end of the shorter Litz wire (going to the AN2 circuit board point) down in a horizontal position as shown, and using a MINIMUM of heat (and no additional solder), solder the pre-tinned Litz wire end to the AN2 circuit board point while the wire is in a horizontal position. Carefully observe the connection to ensure that there are no solder bridges to the adjacent circuit board components. After ensuring this, temporarily move the 1” (25 mm) section of shrink tubing away from the end of the longer Litz wire, and following the detailed procedure described for the AN2 connection above, carefully solder the end of the longer Litz wire to the AN1 circuit board point in a horizontal position as shown, using a MINIMUM of heat (and no additional solder). Once again ensure that there are no solder bridges to adjacent components, and that the wire is in a horizontal position, as shown. Then slide the 1” section of shrink tubing down over the Litz wire to the position shown in the photo.

20)   Refer to the photo above. After ensuring that your Litz wire connections and the wires’ positions resemble those in the previous photo, take the PL-380’s back cabinet section and carefully bring it close to the radio, as shown in the photo. Ensure that the whip antenna’s lead-in wire is not pinched, and also ensure that the 4” (102 mm) section of shrink tubing is routed is a position close to the empty wrist strap hole in the back cabinet, as shown. As a first step, carefully mate the radio’s back cabinet to the radio’s right side (the one opposite the wrist strap hole) while continuing to guide the shrink tubing through the wrist strap hole. Finally, center the shrink tubing in the wrist strap hole while mating the remaining (left) side of the cabinets together. Ensure that the shrink tubing is not pinched or extremely tight as it is clamped down in this hole. While holding the two cabinet sides together move the whip antenna up and away from the cabinet screw hole underneath, and insert the first cabinet screw, tightening it temporarily to keep the shrink tubing in position. Then insert and tighten the left upper and left lower cabinet screws thoroughly, while snapping the right lower cabinet sections together. Finally, after ensuring that the Litz wires’ shrink tubing is still in the center of the wrist strap hole without any binding or excessive stress, tighten the final cabinet screw near the whip antenna base. Reinstall the two small battery compartment screws and reinsert batteries.

INITIAL TESTING   If you are not familiar with the PL-380, make sure that you study the owner’s manual to find the location of basic operating controls. It is important to initially test the radio in a location free of computer noise or other RF pollution—preferably in an outdoor location where its capabilities can be appreciated. Refer to the photo on the next page. Turn on the radio and select the Medium Wave band (530-1700 kHz in North America) and set the AM bandwidth control to the most selective (1 kHz) position (NOTE: This position also provides maximum MW and LW sensitivity for the model, although the higher audio frequencies are limited somewhat by the sharp DSP filtering). If your FSL antenna transplant is working properly you should notice an EXCEPTIONAL increase in the signal strength of weak fringe stations relative to the stock PL-380 model, and a very significant increase in fringe station strength relative to a 7.5” loopstick PL-380 model. Check fringe station strength across the band, and you should notice MW reception far superior to that of any stock portable in your collection. If you are not receiving any MW signals the problem is usually easy to trace—either one of the PL-380 circuit board connections is shorted to adjacent components because of too much solder, or the physical stress on the Litz wires (because they were not soldered in a horizontal position) has caused the circuit board connections to break off and separate from the board. In the first case you can attempt to remove excess solder by turning the circuit board upside down and melting the excess solder onto the tip of your soldering iron (or using a “solder sucker” in a normal position), but in the second case you will probably need a technician to restore proper function to your radio. Fortunately both of these problems are rare, and can be entirely avoided by carefully following the instructions in Steps 18 and 19.

OPERATION

The triple advantage of superior FSL sensitivity, powerful audio amplification and sharp DSP selectivity provide this breakthrough model with exceptional weak-signal performance for a portable—to the extent that after a few DXing sessions the operator may have the impression that the realm of science fiction has been approached. The cylindrical shape of the FSL antenna seems to provide a bonus capability of unusual nulling function as well, so that multiple weak signals can be received adjacent to (or on the same frequencies as) local pests.

During DXing sessions it is a good idea to support both the PL-380 and FSL antenna frame in the same hand (as shown in the photo above), and also to avoid sudden mechanical stress or bumps to the antenna frame. When constructed according to this article the glue bond between the antenna frame and PL-380 is sufficient for routine operations, but the DXer should exercise care to avoid bumps, drops or other stress. The FSL antenna itself is fairly rugged, as constructed.

Refer to the photo on the previous page. The PL-380 has many digital search functions and advanced capabilities for a pocket radio, but some of the functions of particular interest to the transoceanic DXer are described here.  The “AM Bandwidth” switch allows you to choose different levels of DSP filtering to limit splatter from domestic pests, and is usually left in the 1 kHz position for the narrowest filtering while chasing transoceanic DX (although this position does cut off some of the high frequency audio from the desired DX station). The 9/10 kHz switch allows you to change the tuning steps of the radio from the North American (10 kHz) band system to those of the European/ African/ Asian/ Pacific band system (9 kHz), depending upon your preferred DX targets. The MW / LW switch allows you to switch over to Longwave DXing—and you will be pleasantly surprised to discover that your newly installed 3” Bar FSL antenna is FAR more sensitive on the Longwave band than the stock PL-380 loopstick. Finally, the Display switch offers you multiple options while chasing transoceanic DX—you can have a 24 hour clock display,  a display of the alarm time set in the radio, a constantly changing readout of DX signal strength and S/N ratio, or a temperature display (in either Celsius or Fahrenheit).

Because the antenna frame has been trimmed to allow full operation of the PL-380’s whip antenna to receive SW and FM signals, it’s possible to check the Shortwave parallels of Medium Wave DX stations (and switch back and forth) within a couple of seconds. In general, this “science fiction” PL-380 model’s sensitivity and selectivity will allow you to experience the most exciting AM-DXing fun that a portable can offer—and do so at an unbeatable price.

This hard-wired FSL-enhanced PL-380 model is the first in a series of portables designed to be the ultimate “travel radios,” with DXing potential superior to any stock design. It has been a great thrill to design, construct and introduce this model, which is pretty fanatical in both its appearance and DXing capabilities. My hope is that its function will inspire those who build and use it, and help them share my impression that the MW-DXing hobby has a very innovative and exciting future!

73 and Good DX,

Gary DeBock

Gary, I can only imagine the time and patience it took to document this procedure. Once again, thank you so much for doing so! I have a Tecsun PL-380 and I will–some day–make this “science fiction” mod! 

In response to our post about the high-gain ferrite bar antenna for the Tecsun PL-360/PL-365 and CountyComm GP5/DSP and GP5/SSB, SWLing Post contributor, Ron, writes:

…and it’s worth it.

On MW there is a marked difference on both the low and high ends
of the band, just as the builder said, compared to the stock plugin antenna.

On longwave my local NDB BH went from being barely audible on the stock
plugin to being quite readable–well above the noise.

The seller replied to a question about it being shipped very quickly
since it never did track on USPS.

Good seller, reliable email, good antenna that works as claimed–no problem here.

Click here to view the antenna on eBay.

Thank you so much for the report, Ron!

SWLing Post contributor, Gary DeBock, is an acclaimed innovator in the realm of Ultralight DXing–he’s well-known for constantly pushing the envelop on these inexpensive DX receivers.

Gary has published yet another detailed home-brew project that can turn your stock Tecsun PL-380 into a Mediumwave DX Fiend!

Many thanks to Gary for the following guest post:

“Pest Control” 4.25” FSL Tecsun PL-380

Put Your Local Noisemakers Down for the Count with this Breakthrough Model

By Gary DeBock, Puyallup, WA, USA

February 2016

Introduction  

The first portable radio with a transplanted FSL antenna was introduced last month (click here to read), providing breakthrough MW-DXing performance in the pocket radio class. Although this 3” Bar FSL Tecsun PL-380 exceeded expectations in every way, its 100mm ferrite bars were in very short supply.

By coincidence the final eBay seller of these 100mm x 20mm x 3mm Russian surplus bars (in Romania) stopped selling them on the day that the first model was finished, creating an instant rush in demand. After providing twelve sets (of 8 bars each) to various DXers my own stock of these bars was rapidly dwindling, and it became an urgent matter to design a similar model using the plentiful 62mm x 12mm x 4mm ferrite bars. Sensitivity of the new FSL antenna would need to be fully competitive with the original model, and I was hopeful of a design that would offer at least one new DXing advantage.

With the shorter (62mm bars) it would require a larger diameter FSL antenna to come close to the original model in sensitivity, so by necessity this alternative model would need to have a “short and stubby” FSL coil design. After considering this I recalled that most of the antennas with a reputation for exceptional nulling performance (and direction finding) seemed to have such a “short and stubby” coil design—so why not take this opportunity to design and create a portable radio with breakthrough nulling performance, in addition to its superior sensitivity? Such a combination would hopefully make the new model an innovative performer in urban areas—a portable radio that could not only silence multiple MW “pest” stations, but also provide unusual sensitivity to receive competing stations right on the same frequencies. As the model was developed several technical discoveries were made to improve nulling performance, such as the use of grounded shield foil for the Litz wires, and an ultra-symmetrical FSL coil. But even if you live in a rural area far from any MW stations, you will find that this modified radio has a great deal of performance to offer— a combination of sensitivity, selectivity and nulling ability that has never existed in portable form.

Project Overview  

This modification procedure will convert the Tecsun PL-380 AM-LW-FM-SW portable from a modest-performing Medium Wave receiver into an exceptional one, with a significant enhancement of Longwave performance as well. The process involves some close-order soldering on a crowded PL-380 circuit board, and should only be attempted by those will good close-up eyesight, steady hand coordination and some soldering experience. The process also involves the winding of a highly symmetrical antenna coil, which is essential for optimal nulling performance. Because of this, careful attention to the instructions and the use of the recommended ferrite bars and Litz wire is important for the best performance. Certain component parts may be in short supply depending upon current demand, and it is recommended that all these be collected prior to starting the modification procedure.

Since major portions of this project involve duplication of procedures contained in the PL-380 7.5” Loopstick Transplant article, reference is made to various steps and instructions in that article (posted here). As such, hobbyists who have successfully completed the 7.5” loopstick transplant project on a PL-380 will find this procedure relatively simple, with only the 4.25” Bar FSL construction as a new challenge. The resulting FSL-enhanced PL-380 truly provides a quantum leap in MW-DXing performance over the stock model, but reasonable care is necessary to protect the modified portable from sudden drops or mechanical shocks. Completion of the finished radio should provide a great level of satisfaction and hobby enjoyment, especially during travel opportunities where external antennas are impractical or forbidden.

Construction Parts Required

A.) Tecsun PL-380 AM-LW-FM-SW Receiver (available from multiple sources on eBay)

B.) Precut section of Ace Hardware 48″ orange plastic carpenter’s level (dimensions to follow)

C.) 2.6″ long section of the 3.5″ diameter “Big Boss Noodle“

D.) 22 Russian surplus 62mm x 12mm x 4mm ferrite bars

E.) Tube of Duro Super Glue, .07 ounce (or equivalent)

F.) Two 1″ x 1/2″ strips of 1″ I.D. rubber heater hose

G.) 7 1/2″ of 1/8″ diameter shrink tubing

H.) Two 18″ long plastic tie wraps, 125 lb. test

I.) Oatey 4″ x 4″ foam closet spacer pack

J.) Roll of Rite Aid 1″ wide waterproof tape

K.) 40 feet of 250/46 Litz wire

L.) Roll of Scotch “Extreme” shipping tape (any size)

Miscellanious:

• 8 1/2” x ¾” strip of heavy duty aluminum foil (Reynolds or equivalent)
• 3” long #18 hookup wire
• 25w pencil-type soldering iron
• solder
• hacksaw (or power miter saw)
• hand tools

PL-380 Preparation  

Before voiding the warranty on your new PL-380, it’s a good idea to ensure that it has no existing problems which might require warranty service J Install batteries in the radio and give it a test run on all four bands, checking the tuning encoder, clock, volume control, speaker, headphone jack, display functions and digital searching modes. Make sure that the radio is working properly in all functions before starting the modification procedure, since the eBay sellers are unlikely to show you any sympathy after you tear out the stock loopstick. It’s also a good idea to check out the Medium Wave weak signal reception with the PL-380 stock loopstick before starting the modification, to establish a benchmark of performance against which the new 4.25” FSL’s DXing performance will be compared.

Step-By-Step Construction

1) Follow the detailed cutting procedures in steps 1-9 of the loopstick transplant article (using either a power miter saw or hacksaw) to prepare the FSL antenna mounting frame, HOWEVER please note that the top section length for this project is 3 1/4” (82 mm), NOT 8” as in the loopstick transplant project. The finished precut frame should resemble the picture to the left, with the top section flat, and the bottom section back edge trimmed to allow full use of the radio’s whip antenna. The frame’s entire bottom section (including the glue surface) is identical in both the loopstick and FSL transplant projects.

2) Follow the detailed procedures in steps 17-22 of the loopstick transplant article to prepare the PL-380 cabinet for the FSL transplant procedure.

3) Refer to the photo above (NOTE: These photos show the original FSL frame cut for the longer 100mm bars, which has a longer top section length than the 3 1/4” on this project’s FSL frame. Ignore this aspect). Place the prepared PL-380 cabinet in the vertical position as shown, with a paper roll (or other item) to keep the cabinet in the vertical position. If necessary sand the edges (only) of the antenna frame’s glue surface to ensure that no cutting debris or rough edges will cause an uneven gluing surface. Use a clean, damp cloth or paper towel to remove all dust and debris from both the antenna frame and PL-380 glue surfaces, then wipe them thoroughly dry. Ensure that maximum light shines on the PL-380’s top glue surface (as shown in the photo below), then practice making multiple “dry runs” of placing the antenna frame directly centered on the PL-380’s front top cabinet surface, with its front edge lined up with the PL-380’s beveled front edge. You will only get one chance to place the frame accurately when the super glue is on the PL-380 surface, so make sure that you know exactly what to do! The antenna frame should sit completely flat against the PL-380 cabinet, and slide across it smoothly if such a test is made. If not, sand any rough edges on the antenna frame’s glue surface and repeat the cleaning procedure.

4) Refer to the photo above. After ensuring that you are fully prepared for accurate placement of the antenna frame on the PL-380 cabinet, place a 4 1/2” x 3/16” bead of super glue (114 mm x 5 mm) on the PL-380’s front top cabinet surface, as shown in the photo. Refer to the photo on the top of the next page. Ensure that the front side of the antenna frame (as shown) is facing you, then place the antenna frame in a centered position flat against the PL-380 cabinet, with its front edge lining up with the front beveled edge of the cabinet, as shown in the photo. Press the antenna frame down firmly against the cabinet for about one minute, scraping away any excess glue from the front and back edges with a small, flat jeweler’s screwdriver. It is especially important to remove any excess glue from the back edge of the antenna frame in order to allow the PL-380’s back cabinet to close normally. After completion of this step place the PL-380 (with the attached antenna frame) in a secure area until the FSL antenna is constructed.

Construction of FSL Antenna

5) Refer to the photo at right. Take the precut section of “Big Boss Noodle,” and ensure that the top and bottom cut faces are perfectly straight. Place the section flat on the table as shown, and carefully wrap two lengths of the 1” waterproof tape tightly around the noodle’s circumference, adhesive side out (as shown). Ensure that these tape strips are parallel, and tight enough not to slide up or down. Take a perfectly straight 62 mm bar and press it tightly up against the tape as shown, with its lower edge flat on the table and its longer edges parallel to the noodle’s edges.

6) Refer to the photo at right. Carefully press the remaining 21 bars against the waterproof tape, ensuring that their lower edges are flat against the table, and that there are no major gaps in between any bars. (NOTE: These bars occasionally have slightly curved edges, and it may be necessary to turn them upside down or backwards in order for them to fit in well with the adjacent bars. When all of the bars are carefully placed, 22 of them will fit exactly on the noodle’s circumference. If necessary, pull certain bars off of the tape and reposition them for a better fit).

When all 22 bars are positioned in a tidy pattern, wrap two strips of the waterproof tape tightly around them as shown, with the adhesive side out. It is OK if the two tape strips slightly overlap (as shown in the photo), but the two strips should be tight enough so that they don’t slide up or down, and also tight enough to secure the ferrite bar assembly in a circular pattern.

7) Refer to the photo at right. Remove the inner staple from the Oatey foam, and locate a 14” (35 cm) length of the foam which is free of holes or imperfections. Cut a straightedge at the beginning of this 14” (35 cm) length of foam, and press this foam edge down on the tape at the position shown in the photo at right, perpendicular to the side of the bar assembly and with one edge of the foam length lined up with one edge of the bar assembly. Wrap the foam length tightly around the circumference of the bar assembly, stretching it slightly to keep it completely flat and lined up with the bar assembly edge. After the foam strip is tightly and completely wrapped around the bar assembly cut another straightedge to mate evenly with the first straightedge, ensuring that there are no gaps or overlaps along the two edges. If necessary, re-stretch and trim the foam strip to mate evenly with the first edge. After once again ensuring a tight wrap of the Oatey foam, secure the two edges with a 3” (76 mm) strip of waterproof tape, as shown in the photo on the previous page.

8) Place the assembly in the position shown in the photo at right. Take scissors and trim the loose edge of the Oatey foam so that it is even with the other edge of the bar assembly, as shown in the photo at left. After this trimming both edges of the assembly should be flat, with the assembly forming a perfect cylindrical shape (as shown).

9) Refer to the photo below:

Place the assembly on one of its edges, as shown. Take the waterproof tape and tightly wrap one strip along the direct center of the assembly as shown, with the adhesive side out. Ensure that this strip of tape is tight enough so that it will not slide up or down by itself, and then cut the tape with a 2” (51 mm) overlap. If necessary (after wrapping this tape), shift the position of the tape slightly to ensure that it is running along the direct center of the assembly before proceeding with the next step.

10) NOTE: The symmetry of your Litz wire coil will be a major factor in determining the nulling capability of your modified PL-380. When winding the coil keep the Litz wire turns as tight and straight as possible, with no gaps or overlaps.

Refer to the photo on the right. Take the roll of 250/46 Litz wire and measure off 16” (41 cm) from the end. While holding this Litz wire point with one hand pick up the bar assembly with the other hand, and press down the (16”) Litz wire point with the wire parallel to the edge of the tape and 1/8” (3 mm) distant from it, as shown in the photo at left. Keep thumb pressure on this (16”) point while carefully winding a tight first turn of Litz wire around the circumference of the bar assembly, accurately maintaining the 1/8” (3 mm) distance from its edge. After this first Litz wire turn is wound tightly and accurately around the bar assembly it will set the pattern for the remaining turns, which only need to be tightly wound adjacent to the preceding turn.

Since the waterproof tape is wound with the adhesive side out on the assembly, if you need to take a break while winding the Litz wire coil place the assembly down on its edge, not on the adhesive side of the tape. Wrap the second turn tightly adjacent to the first turn, checking around the circumference of the assembly to ensure that there are no gaps or overlaps in the Litz wire turns. Continue this careful process until the entire coil has been wound, as described in the next step.

11) Refer to the photo at right. Continue winding tight, straight turns of Litz wire (with no gaps or overlaps) until the turns are within 1/8” (3 mm) of the other side of the tape. At this point you should have around 21 turns in your Litz wire coil, although the number of turns is not nearly as important as the symmetry of your coil. It should appear completely straight down the center of the assembly, as in the photo at right.

12) Refer to the photo below.

Take the Scotch “Extreme” tape and place a strip across the Litz wire coil at the exact start point (where the 16” point was first pressed down on the tape), ensuring that 16” of loose Litz wire still extends beyond this point for hookup purposes. Ensure that the “Extreme” tape strip is perfectly perpendicular to the Litz wire coil, and that there are no “bubbles” or major wrinkles along its length. Press this tape strip firmly down over the Litz wire coil to secure the coil in a symmetrical position, then trim the ends of the tape even with the edges of the bar assembly.

13) NOTE: To the maximum extent the two ends of the Litz wire coil should be secured by the Scotch “Extreme” tape so that they leave the coil as close together as possible, with no loose runs of single Litz wire along the coil. This factor (along with the use of a grounded shield around the lead-in Litz wires) has proven to have a major effect on the nulling capability of the FSL coil.

Refer to the photo at right. Place a second strip of Scotch “Extreme” tape across the Litz wire coil directly below and within 1/8” (3 mm) of the first strip, securing the other end of the coil where the Litz wire leaves the assembly. Once again ensure that 16” (41 cm) of loose Litz wire extends from the coil, then cut the Litz wire at that 16” (41 cm) point. Ensure that both Litz wires leave the coil freely without binding or kinks, and that the second strip of “Extreme” tape also has no “bubbles” or major wrinkles along its length. Press this second strip of “Extreme” tape firmly down over the coil to finally secure the coil in a symmetrical position, then once again trim the ends of the tape even with the edges of the bar assembly.

14) Refer to the photo above. Take the FSL assembly, 8 1/2” x 3/4” strip of aluminum foil and the 7 1/2” length of 1/8” shrink tubing and place them in the positions shown. Place the strip of aluminum foil under the Litz wires, with the Litz wires running about 1/4” from the right edge of the strip of aluminum foil. Starting as close as possible to the FSL coil (where the Litz wires leave the coil), make a lengthwise fold in the aluminum foil from right to left, covering over the Litz wires for the first 7 1/2” of the aluminum foil (leave 1” at the end of the foil, which will not be folded).. Ensure that the Litz wires are within this initial fold for the 7 1/2” length, then make a second lengthwise fold in the aluminum foil from left to right to securely wrap the Litz wires inside the foil for this first 7 1/2” length. Finally form the aluminum foil into a tight circle as shown, ensuring that neither of the Litz wires is exposed throughout this 7 1/2” length of the foil, and that they are both tightly wrapped in the foil. Also ensure that this entire length of the foil-wrapped Litz wires is of a small enough diameter to easily pass through the 1/8” shrink tubing.

15) Refer to the photo at right. Form the 1” end of the aluminum foil (which does not wrap around the Litz wires) into a compact cylindrical shape, as shown (NOTE: the foil is relatively fragile, and should be handled carefully). Take the loose ends of the Litz wires and pass them through the 1/8” shrink tubing, including the prepared end of the aluminum foil as it approaches that point. While grasping the Litz wires on the right side (as shown) carefully slide the shrink tubing toward the FSL coil, ensuring that it smoothly covers over the foil-wrapped Litz wires (if not, continue forming the aluminum foil into a smaller diameter so that the shrink tubing will easily cover over it. This process should go smoothly with proper preparation). When the shrink tubing is completely covering up the foil-wrapped Litz wires the last 1” section of the aluminum foil should be extending out of the right side of the shrink tubing, as shown in the photo. Handle this aluminum foil section with care in the remaining steps—it is relatively fragile, and should never be pulled for any reason.

16) Refer to the photo at right. Place the viously prepared PL-380 and antenna frame assembly flat on the table, with a protective cloth to keep the front panel display from damage. Take the prepared FSL antenna assembly and place it in the position shown, with the shielded Litz wire shrink tubing running along the back side of the antenna frame, and with the lower edge of the FSL assembly next to the top of the antenna frame. Place the two 1” x 1/2” strips of rubber heater hose in the two positions shown, in between the antenna frame and the FSL antenna and also in between the coil and the FSL edges, with the longer rubber strip dimensions parallel to the FSL edges. Start the two 175 lb. test plastic tie wraps in the positions shown (down the center of the rubber spacer strips), ensuring that the rubber spacer strips remain between the FSL assembly and the antenna frame, and that the spacer strips are centered at the very bottom of the FSL assembly. Also ensure that the Litz wires are in the position shown, with no pinching or binding between the FSL assembly and antenna frame. Slowly and carefully tighten the first plastic tie wrap while ensuring that the rubber spacer strip remains in the proper position. Tighten this plastic tie wrap only enough to securely hold the FSL assembly, and do not tighten it to the point where the ferrite bars’ circular pattern becomes distorted. In a similar manner, carefully tighten the other plastic tie wrap while ensuring that the rubber spacer strip remains in the centered position, in between the antenna frame and FSL assembly. Once again, tighten this tie wrap only enough to securely hold the FSL assembly, and not to the point where the ferrite bars’ circular pattern becomes distorted. When this process is complete the large plastic tie wraps’ clamps should be in the position shown, lined up with each other and in a position to support the radio/FSL combination when the model is laying down flat, on a table. Cut off the excess tie wrap lengths.

17) Refer to the photo at right.   Temporarily place the Litz wires down along the radio’s circuit board in the position shown. Locate the detailed circuit board antenna connection points “AN1” and “AN2” in the close up photo at the top of the next page. After locating these two circuit board connection points (with the Litz wires running in the position shown in the photo at left) place one of the Litz wires over the “AN1” circuit board point, and the other Litz wire over the “AN2” circuit board point. Then measure out about 1” (25 mm) extra Litz wire past these two circuit board connection points, and after making sure that the Litz wires are still in the approximate position shown in the photo at the beginning of this step, cut one (shorter) Litz wire 1” (25 mm) past the “AN2” circuit board point, and one (longer) Litz wire 1” (25 mm) past the “AN1” circuit board point.

NOTE: The proper procedure of tinning the ends of the Litz wires requires that all of the individual Litz wire strands be soldered together at the ends. This requires a clean, shiny solder connection all around the circumference of the Litz wire ends for at least 1/8” (3 mm). When preparing the ends of the Litz wires in the next step, ensure that the ends are tinned in this manner before continuing.

18) Refer to the photo above. Temporarily remove the Litz wires from the PL-380 cabinet and place them in the position shown, with a protective surface over your work table to avoid hot solder damage. Carefully tin the ends of both Litz wires in the manner described above, working around the circumference of the Litz wire ends with a clean soldering iron for at least 1/4” (6 mm). After doing this, cut off the tinned section on both ends to a length of 1/8” (3 mm). When viewing the ends of the Litz wires after tinning, the entire 1/8” (3 mm) length should be bright and shiny all around its circumference, as shown in the photo at the top of the next page. The cut surface of the Litz wire (the circular face) should also be bright and shiny, with one solid surface of melted solder. Do NOT attempt to tin the 1” section of aluminum foil.

19) Refer to the photo above. Position the shrink tubing as shown, with the tubing entering the PL-380 cabinet near the corner where the wrist strap was previously located. Ensure that there will be sufficient slack in the shrink tubing (as shown) to route it through the empty hole left by removal of the wrist strap without binding (after this hole is enlarged to fit the shrink tubing diameter). Take a small, flat screwdriver and carefully pry apart the cabinet clamp as shown—so that it is wide enough to grip the shrink tubing, but not so wide as to break off.

Ensure that the circuit board points “AN1” and “AN2” still have a small amount of melted solder on them (after removal of the PL-380 stock loopstick, as described in the Loopstick transplant article). Also ensure that there is no excessive length in either of the Litz wires, since these both must be positioned as shown (if necessary, cut one or both to the proper length, and re-tin them as described in the previous step). Place the end of the shorter Litz wire (going to the AN2 circuit board point) down in a horizontal position as shown, and using a MINIMUM of heat (and no additional solder), solder the pre-tinned Litz wire end to the AN2 circuit board point while the wire is in a horizontal position. Carefully observe the connection to ensure that there are no solder bridges to the adjacent circuit board components. After ensuring this, following the detailed procedure described for the AN2 connection above, carefully solder the end of the longer Litz wire to the AN1 circuit board point in a horizontal position as shown, using a MINIMUM of heat (and no additional solder). NOTE: After soldering these connections do not attempt to force either Litz wire down in a horizontal position. Re-solder them in a horizontal position if it is necessary to get them flat against the circuit board.

20) Refer to the photo at right. Take the 3” length of #18 hookup wire and strip off 1/4” of insulation from one end, and 3/4” of insulation from the other end. If you are using stranded wire, twist the individual strands together on each end of the wire. Tin a small amount of solder on the shorter (1/4”) bare length. Locate the “GND” marking on the circuit board as shown in the photo, and using maximum care to keep the wire as flat as possible against the circuit board, solder the tinned end of the hookup wire to the large ground connection on the circuit board immediately to the left of the GND marking. Use only a minimum of heat to make a securely soldered connection, and ensure that there are no solder bridges to adjacent areas.

Cut a 3/4” x 1” section of Scotch “Extreme” tape. While holding the other end of the hookup wire next to (and making a secure electrical contact with) the 1” end of the aluminum foil coming out of the shrink tubing, slide the strip of “Extreme” tape under the connection, and securely wrap the tape around the connection (as shown) to permanently secure the two conductors together. MAKE SURE that these two conductors have a good electrical contact under the tape before continuing, since this connection is important for the model’s optimal nulling capability. During this process avoid rough treatment (or pulling) of the aluminum foil, since it is relatively fragile and easily separated.

21) Refer to the photo above. Using small diagonal cutters carefully clip off small pieces of the back cabinet’s wrist strap hole so that it will be of a similar size to that of the shrink tubing, in order to run the shrink tubing through without any pinching or damage. Ensure that the cut pieces do not fall inside the PL-380 cabinet.

Take the PL-380’s back cabinet section and carefully bring it close to the radio, as shown in the photo. Ensure that the whip antenna’s lead-in wire is not pinched, and also ensure that the shrink tubing is routed is a position close to the empty wrist strap hole in the back cabinet, as shown. As a first step, carefully mate the radio’s back cabinet to the radio’s right side (the one opposite the wrist strap hole) while continuing to guide the shrink tubing through the wrist strap hole. Finally, using a small, flat screwdriver, center the shrink tubing in the center of the wrist strap hole while mating the remaining (left) side of the cabinets together. Ensure that the shrink tubing is not pinched or extremely tight as it is clamped down in this hole. While holding the two cabinet sides together move the whip antenna up and away from the cabinet screw hole underneath, and insert the first cabinet screw, tightening it temporarily to keep the shrink tubing in position. Then insert and tighten the left upper and left lower cabinet screws thoroughly, while snapping the right lower cabinet sections together. Finally, after ensuring that the shrink tubing is still in the center of the wrist strap hole without any binding or excessive stress, tighten the final cabinet screw near the whip antenna base. Reinstall the two small battery compartment screws and reinsert batteries. This completes the assembly of the 4.25” FSL Tecsun PL-380 model.

Initial Testing

If you are not familiar with the PL-380, make sure that you study the owner’s manual to find the location of basic operating controls. It is important to initially test the radio in a location free of computer noise or other RF pollution—preferably in an outdoor location where its capabilities can be appreciated. Refer to the photo on the next page. Turn on the radio and select the Medium Wave band (530-1700 kHz in North America) and set the AM bandwidth control to the most selective (1 kHz) position (NOTE: This position also provides maximum MW and LW sensitivity for the model, although the higher audio frequencies are limited somewhat by the sharp DSP filtering). If your FSL antenna transplant is working properly you should notice an EXCEPTIONAL increase in the signal strength of weak fringe stations relative to the stock PL-380 model, and a very significant increase in fringe station strength relative to a 7.5” loopstick PL-380 model. Check fringe station strength across the band, and you should notice MW reception far superior to that of any stock portable in your collection. If you are not receiving any MW signals the problem is usually easy to trace—either one of the PL-380 circuit board connections is shorted to adjacent components because of too much solder, or the physical stress on the Litz wires (because they were not soldered in a horizontal position) has caused the circuit board connections to break off and separate from the board. In the first case you can attempt to remove excess solder by turning the circuit board upside down and melting the excess solder onto the tip of your soldering iron (or using a “solder sucker” in a normal position), but in the second case you will probably need a technician to restore proper function to your radio. Fortunately both of these problems are rare, and can be entirely avoided by carefully following the instructions in Step19.

Operation

The triple advantage of superior FSL sensitivity, sharp DSP selectivity and exceptional nulling capability provide this breakthrough model with unprecedented weak-signal performance for a portable—to the extent that after a few DXing sessions the operator may have the impression that the realm of science fiction has been approached.

During DXing sessions it is a good idea to support both the PL-380 and FSL antenna frame in the same hand (as shown in the photo above), and also to avoid sudden mechanical stress or bumps to the antenna frame. When constructed according to this article the glue bond between the antenna frame and PL-380 is sufficient for routine operations, but the DXer should exercise care to avoid bumps, drops or other stress. The FSL antenna itself is fairly rugged, as constructed.

Refer to the photo above. The PL-380 has many digital search functions and advanced capabilities for a pocket radio, but some of the functions of particular interest to the transoceanic DXer are described here. The “AM Bandwidth” switch allows you to choose different levels of DSP filtering to limit splatter from domestic pests, and is usually left in the 1 kHz position for the narrowest filtering while chasing transoceanic DX (although this position does cut off some of the high frequency audio from the desired DX station). The 9/10 kHz switch allows you to change the tuning steps of the radio from the North American (10 kHz) band system to those of the European/ African/ Asian/ Pacific band system (9 kHz), depending upon your preferred DX targets. The MW / LW switch allows you to switch over to Longwave DXing—and you will be pleasantly surprised to discover that your newly installed 4.25” Bar FSL antenna is FAR more sensitive on the Longwave band than the stock PL-380 loopstick. Finally, the Display switch offers you multiple options while chasing transoceanic DX—you can have a 24 hour clock display, a display of the alarm time set in the radio, a constantly changing readout of DX signal strength and S/N ratio, or a temperature display (in either Celsius or Fahrenheit).

Because the antenna frame has been trimmed to allow full operation of the PL-380’s whip antenna to receive SW and FM signals, it’s possible to check the Shortwave parallels of Medium Wave DX stations (and switch back and forth) within a couple of seconds. In general, this “science fiction” PL-380 model’s sensitivity, selectivity and nulling capability will allow you to experience the most exciting AM-DXing fun that a portable can offer—and do so at an unbeatable price.

Nulling Pest Stations

This modified PL-380 was specifically designed to have unprecedented nulling capability for a portable, and when assembled according to the instructions it is capable of razor-sharp nulls on most semi-local and even local MW broadcast stations. Using the nulling function to maximum advantage takes a little bit of practice, and an understanding of the importance of both a horizontal and vertical null angle for different pest stations. It also helps to be in a clean RF environment, away from computer noise, AC house wiring and other limiting factors.

The horizontal null angle is pretty easy to determine—simply point the side of the FSL antenna toward the pest station’s direction until a minimum signal bearing is found. If you have an extremely powerful pest station that makes this impossible to determine on the fundamental frequency, detune the radio (off the pest station’s frequency) by about 10 kHz and try to find the bearing with the minimum pest station splatter .

Once you determine the horizontal null bearing, hold the radio at that bearing and carefully tilt the radio up and down at a slightly vertical angle to determine the absolute minimum signal point. This will be different for each pest station, so it is helpful to write these vertical null bearings down once you determine them, and memorize them if possible. They can be either positive angles (with the radio tilted upward) or negative angles (with the radio tilted downward). The point where the vertical null bearing intersects with the horizontal null bearing will always be the direction of the absolute minimum signal—you can picture this as two lines intersecting at a single point in space. Once the side of the FSL antenna is directed at that point, the signal of most pest stations will disappear into the noise. Since this point can be razor-sharp, it is often helpful to support one side of the radio on a “Lazy Susan” type assembly to keep the radio directed at the horizontal null bearing while you are finding the vertical null bearing.

The closer you are located to a pest station the tougher it will become to null it down into the noise—although this particular model will give you the best possible chance of success. Of course if you are located right next door to a 50 kW pest, you will probably need a little more “science fiction” than this model can provide J

This hard-wired FSL-enhanced PL-380 model is the second in a series of portables designed to be the ultimate “travel radios,” with DXing potential superior to any stock design. It has been a great thrill to design, construct and introduce these models, which are pretty fanatical in both appearance and DXing capabilities. My hope is that their function will inspire those who build and use them, and help them share my impression that the MW-DXing hobby has a very innovative and exciting future!

73 and Good DX,

Gary DeBock

Gary, again, thank you for documenting this procedure so thoroughly! No doubt, many a mediumwave DXer can benefit from the excellent nulling characteristics of your “Pest Control” FSL antenna!

Click here to view other tutorials and articles by Gary DeBock.

SWLing Post reader, Lee, writes:

I just wondered if you have ever seen any information about how to tap the I.F of the Tecsun 606 by any chance? I want yo use it for DRM but cannot find any info .
Love the website !

I have not seen info on tapping into the IF of any of the recent Tecsun portables. Can someone help Lee?  I would be very curious how to do this myself.

Many thanks to SWLing Post contributor, Richard Langley, who shares the following:

Latest item, which provides more information, on this previously mentioned news story:

http://www.bbc.com/news/technology-35690688

Here’s an excerpt:

Raspberry Pi computers are being used to power “micro” radio transmitters in Syria.
The Pocket FMs, as they are called, were designed by a German organisation as a way of providing Syrians with independent radio.

The devices have a range of between 4 to 6km (2.5 to 3.75 miles), which is enough to cover an entire town.

At the heart of each is a Raspberry Pi, the credit card-sized single-board computers.
About two dozen have been built, and the designer says they are intended to be as easy to set up as a piece of flat-pack furniture.

“We lost one device in Kobane”, Philipp Hochleichter told BBC Radio 4’s PM programme.

“But due to the bombing – not due to a malfunction.”[…]

Continue reading on the BBC website…

The Raspberry Pi is an amazing little computer; capable of so much at such a low cost. I just purchased a Raspberry Pi 3 yesterday; hoping I can think of a clever way to use it for a little radio fun..

Many thanks to SWLing Post contributor, Jerry Popiel, for the following guest post:

A MW DXing Powerhouse Mini FSL Antenna

by Jerry Popiel

In late February 2016 I completed construction of a modified version of Gary DeBock’s excellent 3 inch Mini FSL design (click here to view).

This new antenna is nothing short of a AM DXing powerhouse with unbelievable sensitivity for receiving stations across the entire AM Bandwidth both day and night. The tuning of stations is razor sharp and it has stunning nulling qualities. Consultation assistance was provided from DXing experts Steve Ratzlaff and Gary DeBock on the project.

Construction Details:

The Antenna was constructed using 9 – 100 mm Ferrite Bars wound on a 2.75 inch diameter x 4 inch styrofoam cake dummy form custom made by in Vancouver, B.C. Canada – (stacy@scoop-n-save.com) for $3.50 plus shipping.

The Coil wire consisted of 38 turns of high gain 660/46 Litz Wire. (Note: As can be seen 38 turns of the thicker Litz Wire left only 5/8” of room on each side of the Styrofoam Form to wire wrap the coil to the ruler frame. A longer Form ie 5” long would work much better for this build).

The insulation spacer used was 2 layers of 1/8 inch Aerotape self adhesive tape which also helped hold the 100 mm Ferrite Bars onto the Styrofoam Coil Form. Inductance measured 356 uH using a DM 4070 Meter which is well within the requirement of over 300 uH for AM Band Reception.

Side View Of 9-Bar FSL Antenna with 2.75” Diameter Styrofoam Cake Dummy.

Because of the extra thickness of high gain 660/46 Litz Wire which is a bit too big to solder to the inside terminals of the Tecsun PL-380 Radio, a 2 Position Terminal Block was superglued to the outside of the Ruler Frame to act as an interface connection point.

2 Position Terminal Block Superglued To Back Of Antenna Frame

Testing Results:

Both daytime and evening AM station captures have been spectacular. Stations as far away as KKOB / 770 kHz Alberquerque, New Mexico 1130 Miles from here in Winnipeg, Manitoba, Canada have been received. Country music station WSM / 650 kHz in Nashville, Tennessee 1082 miles distant is a daily evening pickup.

Station KKOB / 770 kHz Alberquerque, New Mexico 1130 Miles distance.

Station WSM / 650 kHz in Nashville, Tennessee 1082 miles distance.

Two Stations Received At 600 kHz 90 Degrees apart at the same time:

The amazing Nulling and Razor Sharp Tuning quality of this FSL was demonstrated when 2 stations at 600 kHz were received at the same time by rotating the Radio with attached FSL 90 degrees. In the North / South direction Station KSJB / Jamestown, North Dakota (219 miles distant) was received with a strong signal strength of 50 / 23. Then by rotating the Radio 90 degrees to the East / West direction Saskatoon, Saskatchewan station CJWW (442 miles distance) was captured with a similar strong signal strength of 44 / 24.

600 kHz Station KSJB / Jamestown, North Dakota.

600 kHz Station CJWW / Saskatoon, Saskatchewan.

Daytime Reception of 600 Watt Station 137 Miles Distant:

A major daily AM reception capture during the afternoon illustrating the amazing sensitivity of this antenna is 600 Watt station KKXL Sports Radio 1440 kHz (137 miles).

All Indoor Reception – For Now!

Due to winter conditions here in Winnipeg, all of the amazing station reception captures in this report were done inside the House facing towards the South window. Fortunately the red ruler platform sides can he used as handles when pointing the radio in the direction of best reception. Exciting times are ahead to see how well this mini 3” FSL will perform outdoors for likely even better AM DXing.

Summarizing:

The design of this new FSL Antenna attached to the Tecsun PL-380 Ultralite radio by Gary DeBock is a major breakthrough in AM DXing since the Radio is attached to the FSL. This new FSL Antenna needs to be constructed to be really appreciated. The application described here requires a bit more skill to construct and is also heavier than the original construction – but at least it is portable. For beginners Gary’s original 3” FSL Heathkit Design is highly recommended and can be reviewed in his You Tube Video posted at: https://www.youtube.com/watch?v=VY9u8MReGjk

Thanks,
Jerry Popiel
Winnipeg, Manitoba, Canada

Thank you, Jerry! It’s amazing what performance you and Gary DeBock have gotten out of these homebrew FSL antennas! Thank you so much for taking the time to share your construction details and performance notes!

Many thanks to SWLing Post reader, Larry Caracciolo, who comments:

I bought the AN-200 in the spring of 2015 off of eBay. I was favorably impressed with the product. Comparing it to my old 9′ diameter tuned/shielded loop from 1992, there are some similarities and differences.

The Hallicrafters SX-96 (Image: Universal Radio)

I live in an apartment complex so plenty of radiated electromagnetic noise is present. I use a modified [Hallicrafters] SX-96 (AVC ckt was modified for improved modulation acceptance). The AN-200 does null out local static sources, somewhat, but not well enough to dig out weak stations. The tuning range for the loop is just at the bottom of the AM band (about 535 khz) to just over 1700 kcs.

On a whim, I wrapped aluminum foil around the loop and grounded it to the SX-96 chassis – in wistful hope of achieving some shielding from the RF has. As soon as I connected the aluminum foil ground clip to the rx chassis, all RF noise ceased and signals appeared from the mud. However, the tuning range is attenuated above 1200 kcs.

My favorite frequency on the AM band is 590 kcs. During the night, as many as seven different stations rose from the noise and provided station IDs at just the right moment. My best catch here in Everett, WA is KCSJ, a 1KW station in Colorado Springs.

From time to time, stations on the low portion of the AM band are accompanied with echoes – what I took for two stations and a small time delay between the same broadcast was actually multi-path to the degree that nearly 1/2 second separated the arriving signals. Short-delayed echoes, anyone? I’ve not observed this on frequencies above 1000 kcs.

Other sources of RF noise can come from the laptop, the cable modem, and even CFBs in other rooms. For truly noise-free listening environment, I place the laptop in sleep mode and unplug the cable modem. I’m quite happy with the AN-200 loop. Affordable, easy to use, easy to tune.

Thanks so much for sharing your experience with the AN200 loop antenna, Larry!

As anyone who grew up in the era of TV rabbit ears knows, aluminum foil can simply work magic in a pinch! There is no easier material to work with either!

As I pointed out in previous posts, the AN200 loop antenna is quite affordable.  I just did a quick price search:

• The Tecsun equivalent of this antenna (the AN100) is available from various sellers on eBay from about $15 – $30 US.
• The Kaito AN200 (Kaito’s branded version) is available on Amazon for $30 shipped.
• With the purchase of the Eton-Grundig Traveler III,  Eton-Grundig Field, or Eton-Grundig Satellit, Universal Radio will include a free AN200 with your purchase.