Tag Archives: 2020 Winter SWL Fest

Airspy Youloop and Homebrew Passive Loop Antenna designs

Almost two weeks ago, at the 2020 Winter SWL Fest, I gave a presentation called “A New Era in Portable SDR DXing.

The presentation was essentially an in-depth version of an article I published in the January 2020 issue of The Spectrum Monitor magazine (see cover above).

I devoted a good portion of the presentation describing how to build a passive loop antenna design by Airspy’s engineer and president, Youssef Touil. This passive mag loop takes advantage of the Airspy HF+ Discovery‘s exceptionally high dynamic range and is an impressive performer.

The homebrew loop on the balcony of a hotel.

You may recall, I posted a short article about this loop in November after enjoying a little coastal DXing.

In short? This passive loop antenna pairs beautifully with the Airspy HF+ Discovery. I’ve also been very pleased with results using the new SDRplay RSPdx on the mediumwave band where the receiver now sports a high dynamic range mode.

Overdue corrections…

After returning from the Winter SWL Fest last week, I was hit with an upper respiratory bug. No doubt, a souvenir of my travels!  It wasn’t the flu (I was tested), nor COVID-19, but it did knock me off my feet for a few days with fever, coughing, and headaches. You might have noticed a lot less posts last week and almost no replies from me via email. I’m only now feeling totally human again and trying to catch up with my backlog.

Shortly after my SWL Fest presentation, I realized I made (at least!) two mistakes. I had planned to post corrections here on the SWLing Post last week, but the bug delayed all of that, so here you go:

#1 Schematic of my homebrew passive loop antenna

When Youssef started experimenting with passive loop antenna designs, he posted a few schematics of at least three build options.

Although I described how to build my passive loop antenna, I grabbed the wrong schematic for my presentation slides. Many thanks to those attendees who noticed this.

Here is the schematic I should have shared:

Note that the transformer has four turns on both sides (the one in the presentation had 4:2).

Again, apologies for any confusion.

#2 The Airspy Youloop passive loop antenna

If you’re not inclined to build your own passive loop antenna per the diagram above, Airspy is planning to manufacture and sell a lightweight, high-performance loop of a similar design.

Prototype of the Airspy Youloop in the field (note bright blue cable jacket)

During the presentation, I called the future AirSpy antenna, the “Spytenna.” I was incorrect. (Turns out, I got this name from an early antenna schematic and somehow it stuck in my head!)

Airspy is calling their passive loop antenna the Youloop. Youssef posted the following note in the Airspy email discussion group:

We are currently arranging the shipping of the affordable passive version to Airspy.us and RTLSDR Blog.

Btw, It’s called “Youloop”

Many thanks to Richard Langley and a number of other readers who pointed this out last week.

I’ve had a prototype of the Youloop since November and brought it to the SWL Fest and presentation. It’s a quality antenna and incredibly compact when disassembled and rolled up.

When the Youloop is available to order, we’ll post links here on the SWLing Post.

More to come!

Once I catch up here at SWLing Post HQ, I plan to publish detailed construction photos of the homebrew loop antenna.

Many of you have questions about how to tap into the center conductor at the mid-point of the loop. These photos should help guide you.

Stay tuned!


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Rescuing the Eton E1 from a sticky situation

I’m back from a week of travels and the 2020 Winter SWL Fest. In short, is was another amazing Fest and so much fun. I hope to write more about it in the coming days, when I have a few moments to catch up and after I shake a nasty bug (chest cold) I picked up.

Although I had no intention of making purchases at the Fest beyond a few raffle tickets, I couldn’t resist snagging an Eton E1 (XM version) at a silent auction from the estate of our recently-departed friend, Tony Pazzola (WB2BEJ). Tim Moody kindly organized the silent auction.

Tony was an amazing friend to all and an avid radio collector, so there were some excellent radios offered up in the silent auction–I could have easily easy bid on each and every one of them! In the end, though, only one really caught my eye: the Eton E1 XM.

A small sampling of the radios from Tony’s estate.

Tony took amazing care of his radios, but his Eton E1 XM suffered from what all of those models eventually do: a sticky chassis.

Back in the day (roughly 2009 to 2013) Eton/Grundig covared a number of their radios models with a rubberized coating that unfortunately breaks down over time and becomes tacky or sticky to the touch.

I think this E1’s sticky coating put off potential bidders.

It was particularly nasty–if you picked up the radio, you had to immediately wash your hands.

The E1’s starting bid on Friday was $200–quite fair considering this unit is fully-functional and comes with all software, cables, manuals and a SiriusXM radio antenna. By Saturday, the starting bid had been decreased to $150. I resisted putting in an offer, but after seeing that it didn’t sell after all bidding had ended, I couldn’t resist. That E1 needed a good home, right? Plus the proceeds go to Tony’s family.

The sticky coating didn’t scare me. If you’ve been an SWLing Post reader for long, you’ve no doubt read our numerous posts about cleaning off this mess. There are a number of solutions, but I’ve heard the most positive long-term results by employing a de-greasing product called Purple Power (click here to read archived posts). Indeed, it’s the solution Eton Corporation recommends.

On the way home Monday, I stopped by a big box store and grabbed a bottle of Purple Power.

Tony still had the original plastic film on the large backlit display.

Sporting a pair of nitrile gloves, I grabbed a bunch of paper towels and a few cotton swabs, then started the cleaning process. I spent the better part of an hour carefully going over the entire body of the E1and trying to remove residue in every crevice without allowing the Purple Power solution to creep under buttons.

In short?  I’m very pleased with the results and am now a solid believer in Purple Power.

As others have reported, Purple Power breaks down the sticky residue and allows it to be removed with a cloth or towels with very little scrubbing. Indeed, the process was much easier than I anticipate.

Now I have a super-clean Eton E1 XM to put on the air!

Now I have no excuse to finally remove the sticky residue from both my Grundig G6 and G3!

So far, I’m loving the Eton E1. It is, no doubt, a benchmark portable. Of course, another motivation behind snagging this E1 is so that I can compare it with the Eton Elite Satellit once it eventually hits the market.

Do you have an Eton E1?  What are your thoughts about this receiver? Please comment!


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