Category Archives: How To

“Anatomy of a Field Radio Kit” series on QRPer.com

If interested, I’ve now published both parts of my Anatomy of a Field Radio Kit series over on QRPer.com. This series was originally featured in the June and July 2021 issues of The Spectrum Monitor magazine. Here are links to both articles:

These articles primarily focuses on portable amateur radio field kits, but many of the concepts are ones I also use for my field portable receiving setups like this one.

I hope you enjoy!

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Giuseppe’s Homebrew “TFerrite 2” Mediumwave & Shortwave Antenna

Many thanks to SWLing Post contributor, Giuseppe Morlè (IZ0GZW), who shares the following:

Dear Thomas my friend,

I built another Tferrite, (TFERRITE 2), for medium waves–this time also with the shortwave option.

A single variable capacitor, 800 pf, and a primary winding on the 2 ferrites of about 46 turns, a secondary winding of 3 turns to pick up the signal and send it to the receiver.

On the PVC tube I wound 4 more coils, for the shortwaves, connecting the ends to the same variable together with the other ends.

I interposed a switch on one end to eliminate or insert shortwaves.

I am sending you these 3 links from my YT channel where you can see the tests I have done in these days with no propagation.

The yield in mediumwave is excellent, like the other one, yet also good for the shortwaves–to be so small it compares very well.

Let me know what you and the whole SWLing community think!

Thanks to you and a greeting from Italy, Formia on the Tyrrhenian Sea.
73. Giuseppe.

Videos

View on YouTube.

View on YouTube.

View on YouTube.

This is brilliant, Giuseppe! Thank you so much for sharing your homebrew antenna projects. It seems they work so well from your beautiful urban location in Italy!

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Grayhat’s NCPL (Noise-Cancelling Passive Loop) antenna “tweak”

My NCPL antenna

Many thanks to SWLing Post contributor, Grayhat, who shares the following modification he made to a Noise-Cancelling Passive Loop antenna last year. He’s kindly allowed me to share his notes here, but apologized that at the time, he didn’t take photos of the project along the way and recycled many of the components into yet another antenna experiment.

Grayhat writes:

Here’s a simple tweak to the NCPL, made easy for anyone. Let’s start with the commercial NooElec 9:1 balun version 1 (not 2) … made in USA.

Look at the schematic of the balun:

Cut the R1 (0 Ohm resistor – jumper) so that the center tap of the transformer won’t be connected to ground, then solder a short piece of wire to the tap.

The first pic (top) shows the balun seen from top side, the arrow indicates the small hole going to the transformer tap.

This pic shows the bottom of the board with the trace to cut and the spot for soldering the tap wire (needs cleaning with a bit of sandpaper to remove the cover paint). The solder is as easy as 1-2-3 once the trace is cut and the spot cleaned just insert a wire from the top of the board and solder it to the bottom and there you go!

Build the NCPL using “fat” coax (RG8 will do) with the top cross connection.

NCPL modification schematic

Side note: the top “cross connection” is the weak point, so it would be a good idea putting a short piece of (say) PVC pipe over that point, the piece will also help suspending the loop or sticking its top to the support pole, as for the feedpoint, a small electrical junction box will fit and protect the tiny balun from bad weather

Now the difference: connect the two center conductors of the NCPL to the balun input and the braid to the wire going to the center tap (as above).

Such a configuration will give some advantages over the “standard” NCPL one. The loop will now be galvanically isolated from the feedline/receiver so it will have much less “static noise.” Due to the tap, the typical 8 pattern of the loop will be preserved, this means that the loop will now have much deeper nulls.

By the way, the balun could just be wound w/o buying it. I suggested the nooelec since that way anyone with little soldering ability will be able to put it together. Oh and by the way it’s then possible adding a small preamp at the balun output if one really wants, any preamp accepting a coax input will work. 🙂

Again, if you can/want, give it a try !

Many thanks for sharing this, Grayhat! We always welcome your inexpensive, innovative urban antenna projects!

Post readers: If you have question, feel free to comment and I’m sure Grayhat can help. 

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Pedro’s PL-310ET Pro Tip: Controlling ETM scans by changing bandwidth

Many thanks to SWLing Post contributor, Pedro Andrade, who writes:

Hi Thomas!

I’m a noob when it comes to DXing, I only got into the hobby late 2020, and I got to say: I’m hooked. So, sooner or later, I would hit your website/blog. For that, and the continued work in every aspect of the hobby (technical issues, tips, tricks, schedules, etc), I thank you from a noob perspective and from someone that believes the internet is beautiful when it comes to sharing and getting communities together.

That said […]the reason for writing this email, is that I found out that the ETM scan could be very much improved on the Tecsun PL-310et (and I think others).

You simply change the filter sensitivity prior to the scan: the higher the filter the lower the sensitivity. The lower the filter (1 kHz) the higher the sensitivity and thus more stations caught by the scan.

Here’s a video showing it in action:

I hope you find this useful and worth sharing for your readers.

Thanks again for the continued work on the radio side of things.

Regards, Pedro.

What a brilliant tip, Pedro! Thank you for sharing and also for demonstrating in your video! Also, thank you for the kind words about the SWLing Post–an amazing community of folks like you and a pure labor of love!

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Troy’s Tecsun PL-368 Hidden Features Quick Reference Sheet

Many thanks to SWLing Post contributor, Troy Riedel, who shares the following quick reference sheet with all of the Tecsun PL-368’s hidden features:

Click to enlarge image.

Click here to download Excel the spreadsheet.

Thank you so much for creating and sharing this useful chart, Troy!

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Jock discovers the joys of ATS tuning with the C.Crane CC Skywave SSB

Many thanks to SWLing Post contributor, Jock Elliott (KB2GOM), who shares the following guest post:


Really cool trick the CCrane Skywave SSB will do — the “radio butler”?

To paraphrase Ratty from Wind in the Willows: ” “Believe me, my young friend, there is nothing–absolutely nothing–half so much worth doing as simply messing about with radios.”

That is precisely what I was doing . . . messing, simply messing about with the CCrane Skywave SSB.

Then I observed something. Just above the LIGHT button is some lettering: “ATS.” Not having taken notice of it before, I looked it up in the manual. It stands of Automatic Tuning System, and the manual says this about it:

“This feature programs all receivable stations in the AM, FM, Air and Shortwave bands to memory buttons. To use ATS, select your desired band: AM, FM, Air or Shortwave, and press and hold the ATS button for two seconds. The CCrane Skywave SSB will scan the entire band and automatically set all available stations in sequence 1-20. If more than stations are available, then the remaining stations will be preset to the next memory page, and so on.”

So I tried it; I punched in a shortwave frequency — 9250 — and pressed and held the ATS button for two seconds. The Skywave then muted itself and went to the bottom of the shortwave bands — 2300 — and started silently scanning through all of the international shortwave bands, hopping from one shortwave band to the next. Occasionally it would stop and silently store a frequency. After a while it stopped, unmuted, and began playing the very first memory that it stored. I checked the other memories that were stored and — sonofagun! — there were stations stored in each memory. Some of them were really faint, and I had to mess with single sideband and bandwidths to make them fully copyable, but they were there, automatically scanned and stored by the CCrane Skywave SSB. Obviously, you might want to repeat the ATS scan as shortwave propagation changes, say, from day to night.

Well, I thought, would it do it also for Air frequencies? Short answer: it certainly will. And it will do the same for AM, FM, and — get this — if you put the Skywave SSB in single sideband mode, it will scan the ham bands, automatically changing sidebands appropriately as it hops from ham band to ham band. Note: when you check the memories stored during an ATS ham band search, you may not find anything there, simply because ham transmissions come and go much more often than international broadcasters.

There is one downside to the ATS function. When the Skywave scans and stores stations, it does so starting at Page 1, Memory 1 of the memory system . . . always. So, if you scan the Shortwave frequencies and store frequencies they will be stored starting at Page 1, Memory 1, wiping out anything that you have already stored there. If you then use ATS on the Air band, it will then write over whatever you stored from the Shortwave frequencies. I wish there were a way for the user to designate at which page in the memory system ATS will begin storing frequencies so that the information stored starting at Page 1, Memory 1 is not constantly overwritten.

However, there is another trick the Skywave will do: if you have used ATS to scan and store Air frequencies in Page 1 of the memory system (which it does automatically), you can then press and hold the UP and DOWN buttons at the same time, the Skywave will then scan through the Air frequencies that are stored there. Further, there is a squelch function on the Skywave that works only on the Air frequencies. So, with a little persuasion (very little), the CCrane Skywave turns itself into a civilian air scanner.

The ATS function on the CCrane Skywave SSB is a bit like having a radio butler: “I say, Jeeves, find me what’s on the air this evening.” A short while later, Jeeves reports back: “Here you are, sir, I found 10 shortwave stations you might like to listen to.”

Frankly, I don’t know if other modern shortwave portable radios offer a similar function, but if you have a CCrane Skywave SSB, give the ATS function a try; it’s pretty slick.

— Jock Elliott, KB2GOM

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