Tag Archives: Magnetic Loop Antennas

The Great Gonzo Radio Experiment

By Jock Elliott, KB2GOM

It’s funny how you can start out thinking about how to solve a problem, the whole process takes a turn, and you wind up with an unexpected but pleasing result.

It all started innocently enough. Alan posted this — https://swling.com/blog/2024/11/bbc-rd-how-to-test-a-loop-antenna/ — and this statement appeared at the end of a BBC report on how to test loop antennas:

“Polarisation Illustrations of the antenna usually show it mounted upright; that is, with
its axis parallel to the ground. This is fine for the reception of LF and MF transmissions, which are vertically polarised, but most HF transmissions are horizontally polarised.”

When I tested that assertion here — https://swling.com/blog/2024/12/here-we-go-loop-de-loop-in-which-your-humble-correspondent-tests-a-hypothesis/ — there were a couple of interesting responses.

Bob Colegrove said (in part):

“To address your conundrum, from my long-standing, untutored tinkering with loop antennas, I have concluded that, regardless of LW, MW, or SW, optimum performance for peaks and nulls requires that the axis of the loop (i.e., line through the center of the coil) be able to rotate 360 degrees laterally and 90 degrees vertically.” (emphasis mine)

Robert Gulley added:

“I will have to concur with Bob – if I may state it another way, there is no “proper” position for a loop when getting shortwave signals.”

To which I responded:

“I suppose the ultimate setup might be an articulated motorized outdoor mount with a joystick inside that would allow me to fiddle the loop to the optimal position.”

Early in the morning I awoke thinking about how a system capable of manipulating my three-foot-diameter MFJ 1886 loop both vertically and horizontally might be implemented. Everything that came to mind seemed awkward, hard to put together, difficult to operate, expensive, and just plain clunky.

I dozed off and woke up thinking: “What about a really small loop? I could hold it in my hand and easily turn it to different positions to optimize reception, no equipment required.”

A thought came to mind: “You’ve got a small loop antenna, why don’t you see what you can do with it?”

At this point, I need to make my Shameful Admission: I got so intrigued by the idea of using my wrist and hand to turn a small loop to various orientations that I forgot that I was trying to solve the problem of manipulating a shortwave loop.

The loop that came to mind is the Terk AM Advantage. I tested it here. Designed to boost signals on medium wave, it is a nine-inch tunable loop encased in plastic that requires no power supply. It inductively couples with the ferrite antenna inside a portable radio. But I seemed to recall that it also comes with a direct wire connector that can be used with some radios. Perhaps I could connect it to my CCrane EP-PRO which has clips and a switch for an external medium wave antenna on the back of the case.

I found the Terk AM Advantage easily enough, but the direct wire connector required a major archeological dig. Once I unearthed it, I plugged the connector into the back of the Terk AM Advantage, slipped the wires from the connector into the clips on the back of the EP-PRO.

Now to try it out . . .

Tuning slowly down the dial, I found across a very faint signal that I could barely copy. Reaching around the back of the EP-PRO, I switched from the EP-PRO’s internal antenna to the Terk AM Advantage external loop antenna (which I was holding in my hand), rotated it from side to side, tipped it back and forth, and – tah-dah! – was rewarded by a far more copyable signal. It was WEEU in Reading PA, 200 miles away, transmitting 6,000 watts into the darkness on 830 kHz. Switching back to the EP-PRO’s internal antenna, I tried rotating the EP-PRO to optimize the signal but could not produce a signal that was as good as the external loop.

Repeating the procedure with additional faint stations, I got the same results: better reception with the handheld loop antenna, and it was fun and easy to use. I held it in my left hand (it’s light) so I could rotate the dial that peaks the signal with my thumb and working the tuning knob on the EP-PRO with my right hand. It was a very pleasing, almost addictive, experience.

If you’re looking for a potent setup for medium wave DXing, I can recommend the EP-PRO/Terk AM Advantage combo, even though it wasn’t my original objective. Call it serendipity.

In the meantime, does anyone know what might be the smallest loop that could be handheld for shortwave reception and would provide a performance boost over a whip antenna?

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Saturday morning fun: “fat” MW DXing with the MFJ-1886

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By Jock Elliott, KB2GOM

It was a reader, Mario Filippi, who set me on this path. He posted a comment that said, in part: “An interesting place to DX would be the segment between 1500 – 1590 kc’s where there are a number of news stations, one being federal news on 1500.”

Huh, I thought, federal news? I wonder if I can hear that. So I hooked up the MFJ 1886 Receive Loop Antenna to my Grundig Satellit 800 receiver and tuned to 1500. With the 800’s whip antenna, I heard mostly static; switching to the 50-foot indoor room loop, pretty much the same; same thing with the 1886 with the amplifier turned off. But turn the 1886’s amplifier on, and it was like getting slammed against the wall by the schoolyard bully: LISTEN TO ME! A big, fat, S9 signal, sounding like WGY 810 just a few miles from me. Wow, I thought, this loop can really pull out a signal.

A little research revealed, as nearly as I can tell, that Federal News 1500 is in Washington, DC, over 300 miles from me. Over the next few days I would occasionally check on Federal News 1500 using the 1886 loop, and typically it was loud and clear here in Troy, NY.

Hidden behind a curtain, the 3-foot aluminum loop of the MFJ 1886 works well for MW DXing.

Early this morning, Jan. 28, 2023, a thought crept into my brain: how many big, fat, MW signals could I detect with the combo of the Satellite 800 and the MFJ 1886 loop antenna? (Bear in mind that my 1886 rests flat against a window and is NOT rotatable in its current configuration.) Here’s the log, with station IDs when I could get them.

Time Frequency Station

1100Z 1520 WWKB Buffalo

1102Z 1530 Milwaukee? Sports, Australian open

1106Z 1540 CHIN Toronto, old time radio programs

1112Z 1560 religious music

1115Z 1660 orchestral music, Strauss waltzes

1118Z 540 middle eastern music

1121Z 660 WFAN, NYC

1124Z 700 WLW, Cincinnati

1127Z 710 WOR, the Voice of New York

1129Z 730 French language, Canada mentioned

1132Z 750 WSB, Atlanta

1134Z 770 WABC, NYC

1135Z 790 ortho doctor show

1138Z 860 French language, Canada mentioned

1140Z 880 WCBS, NYC

1142Z 1010 WINS, NYC

1144Z 1020 Talk

1146Z 1030 WBZ, Boston

1148Z 1050 WEPN, ESPN radio, New York

1149Z 1060 KYW, Philadelphia, PA

1153Z 1090 WBAL, Baltimore

1154Z 1110 WBT Charlotte, NC

Bottom line: it was immense fun, tuning around for “fat” MW stations in the early AM. Periodically I checked the other antennas as I traversed the band, but universally the MFJ 1886 was better at pulling them in.

Fat station DX? You bet! Try it; you’ll like it!

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A little daytime Medium Wave DXing . . .

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By Jock Elliott, KB2GOM

Let’s get one thing clear from the start: it’s all Ken Reitz’s fault. When the search for the guilty begins, the finger should point squarely at Mr. Reitz.

Who is Ken Reitz? He is the Managing Editor and Publisher of The Spectrum Monitor.

The Spectrum Monitor is a radio hobbyist magazine available only in PDF format and can be read on any device capable of opening a PDF file. It covers virtually aspect of the radio hobby, and you can find it here: https://www.thespectrummonitor.com/ I am a subscriber, and I can heartily recommend it without reservation.

So what is it that Mr. Reitz did that set me off? Short answer: he wrote a really good article entitled “AM DX Antennas: Long Wires and Loops Big and Small.” In it, he mentioned that he could hear, from his location in Virginia, WCBS on 880 in New York City, some 300 miles away. He also mentioned that he could hear, during daylight hours, WGY in Schenectady, NY, about 400 miles distant.

WGY is a local station for me in Troy, NY, but I wondered: Could I hear WCBS in New York City? That’s nearly 150 miles from me. Hmmm.

So I started firing up various radios and radio/antenna combinations on 880 kHz. I tried my Icom IC706 MkIIIG ham transceiver, hooked to the 45-foot indoor end-fed antenna. Nothing heard.

Next, my Grundig Satellit 800 connected to its 4-foot whip antenna. I could hear WCBS barely, but with a horrible buzzing noise. Switching the Satellit 800 to the horizontal room loop antenna I could hear WCBS better, but the noise was really, really nasty.

One way to preserve domestic tranquility is to hide the MFJ Loop behind a curtain!

Then I connected the MFJ 1886 Receive Loop Antenna. Tah-dah! I could hear WCBS just fine, with some noise in the background, but “armchair copy.” The MFJ loop made a huge difference in the quality and strength of the signal. I also tried the MFJ loop with another radio I have under test (its identity to be revealed in the future) and found, while I couldn’t hear WCBS at all with the radio’s internal antenna, the 1886 made an enormous difference, pulling out a fully copyable signal with noise in the background.

Finally, I tried a couple of my portables. My Tecsun 880 could hear WCBS, but the noise level was high enough to be annoying. Finally, I tried my CCrane Skywave SSB. The Skywave did a better job of pulling the signal out of the noise. I got the same result with the CCrane Skywave SSB2. Both Skywaves were using their internal ferrite antennas. Impressive.

Bottom line, for this very small foray into daytime medium wave DXing, the MFJ-1886 Receive Loop Antenna was a powerful and useful tool, one I can easily recommend. Second, when it comes to portables, the CCrane Skywave SSB (either model) continues to show that it is “The Little Radio That Could.”

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Video: Giuseppe tests four classic receivers on three different antennas

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

Dear Thomas and Friends of SWLing Post,

This is Giuseppe Morlè from Formia, central Italy on the Tyrrhenian Sea.

I want to share with you this test with 4 old receivers with 3 different antennas:

- Yaesu FRG-7
- AOR 3030 – MINI WHIP antenna on the roof
- Kenwood R-1000 – INTERNAL CROSSED LOOP antenna
- Yaesu FRG-8800 – VERTICAL NAVAL

I tuned the 7,390 kHz frequency of Radio New Zealand at 14:10 UTC on November 16 on the 4 receivers. I used the narrow and wide filter on each receiver.

I state that a storm was in progress in the area, the afternoon signal was very discontinuous with a difference on the 3 different antennas.

Surprising the result of the internal cross loops which I use a lot when there are thunderstorms in the area to listen to anyway; their behavior is definitely very good despite being inside my shack.

The Mini Whip is excellent on long and medium waves but gets worse above 7 MHz. In fact I only use this antenna for medium and long waves.

A good signal also from the external naval vertical of 8 meters with a “soft” listening on the Yaesu FRG-8800.

Judge dear friends your comments are welcome!

I wanted to compare these 4 “glories” that have accompanied most of my life and that I still consider excellent.

Attached the link tot he video on my Youtube channel:

Click here to view on YouTube.

I wish everyone a good listening …
73. Giuseppe Morlè iz0gzw.

Thank you so much for sharing this, Giuseppe! We love your videos and demonstrations especially since they so often involve antennas that you have home brewed. Your cross loop antenna is truly amazing!

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Testing the MFJ-1886 Receive Loop Antenna

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By Jock Elliott, KB2GOM

Hang out any place online where shortwave listeners gather, and you won’t have to wait long before you hear something like this: “I recently moved to a condo, apartment, or house where there is a home-owners association. Listening conditions are pretty rotten, and I cannot string up outdoor antennas because of physical constraints or HOA rules . . . help!”

Ever since I got back into SWLing nearly two years ago, I have faced similar issues, as I explained here. During that time, I have frequently read that amplified small loop antennas work pretty darn well, and that has piqued my curiosity.

A couple of days ago, the good folks at MFJ (an SWLing.com sponsor) sent me their MFJ-1886 receiving loop antenna. Weighing just 2.5 pounds, the 1886 is a 36-inch-diameter loop of aircraft-grade with an amplifier attached in a weatherproof enclosure. Designed for receiving only, it covers .5 to 30 MHz.

The fit and finish of the 1886 is, in my opinion, great. Looking at the seamless loop and the molded enclosure for the amplifier, I have no reason to doubt what MFJ has to say about it: the MFJ-1886 is weather-sealed, very ruggedly constructed, and mechanically stable under all weather conditions. In fact, you can mount it permanently on any inexpensive TV rotor and direct it from the comfort of your shack . . . it also installs easily on a tripod or handheld mast for portable use.

From MFJ’s manual for the 1886 loop.

Important: the 1886 loop is a directional antenna. If you are looking through the open area in the middle of the loop (the flat side, if you will), you are looking in the direction in which the antenna tends to null out signals . . . in both directions. If you are sighting along the edge of the loop (at right angles to the flat side), that is the direction in which the antenna produces the most gain. As a result, you will get the most utility out of the 1886 if you can mount it in such a way that you can rotate it to maximize gain and/or null out noise or interfering signals as needed.

Since my mission was to test the 1886 indoors, I wrapped some parachute cord around the loop and hung it from a screw attached to the top of a window frame. Obviously, I am not getting the most from the 1886 by keeping it in a fixed position (in fact, I was getting maximum gain to the northeast and the southwest), but I did experiment with the antenna hanging from the ceiling so that it could rotate, and I did, indeed, find that signal strength rose and fell as the antenna changed position.

To see how the 1886 performed, I used my Grundig Satellit 800 as a test bed. The Satellit 800 has three different antenna inputs: a wire input, to which I attached the 50-foot horizontal room loop (an indoor antenna which runs around the perimeter of my radio room at about seven feet in the air); a coax input, to which I attached the MFJ 1886 loop, and the four-foot whip antenna that is built into the Satellit 800. By reaching around the back of the radio and sliding the antenna selection switch, I could easily change from one antenna to another and compare the 1886 loop with the whip and the horizontal room loop at various frequencies and settings.

Setting up the 1886 loop is super easy. First, attach a length of coax to bottom of the amplifier box. (The 1886 uses SO-239 connectors.) Attach that coax to the top of the Bias Tee. The Bias Tee supplies power to the amplifier mounted on the loop using the coax and without introducing noise. Run another piece of coax from the bottom of the Bias Tee to the receiver, and, finally, plug the power supply into the Bias Tee and the house power where you are using the antenna.

Operating the 1886 is even easier. To hear the signal from the loop without amplification, leave the Bias Tee switch in the OFF position. To hear the signal with amplification, just slide the switch to the ON position. That’s all there is to it. There are no fussy adjustments to make.

So how did the 1886 loop perform? Very well, thank you. In all cases, it clearly outperformed the Satellit 800’s whip antenna, providing more signal with less noise. When pitted against the 50-foot horizontal room loop wire antenna, the 1886 typically delivered more signal and less noise. In a few instances, the horizontal room loop was equal to the 1886 loop in terms of signal strength and low noise. In no cases, did the horizontal room loop outperform the 1886 loop.

Tuning around a bit, I found myself listening to a ham from Spain working DX on the 15 meter band. A little further up the band, a ham from central Bulgaria was dealing with a pile-up of U.S. hams trying to reach him. Of the three antennas options I had on the Satellit 800, the 1886 loop offered the most pleasant listening with more signal, less noise.

Then I tried the 1886 with a couple of my portable shortwave receivers. The Bulgarian ham was still on the air and was marginal on one portable and not hearable at all on the other on their native whip antennas. With the 1886 loop connected, however, the Bulgarian was clear and easy to hear. And – thanks to a ham friend who whipped up an additional coax “jumper” with amazing speed – I tried the 1886 loop with the MFJ 1045C active preselector and found the two made a very potent combo for pulling signals out of the mud.

So, would I recommend the MFJ 1886 Receiving Loop for a would-be HF listener who lives in a condo, apartment, or house with antenna woes? Absolutely . . . even if you have to hang it flat in front of a window. And if you can find a way to mount it so that it can be rotated, even better. (Someday, I hope to try the 1886 outside mounted on an inexpensive TV rotator. For now, there simply isn’t room in my cramped radio space.)

Of course, the performance at your location will depend on the conditions where you live. Nevertheless, I found the MFJ 1886 Receiving Loop to be easy to set up, easy to use, and effective.

Click here to check out the MFJ-1886 Receiving Magnet Loop Antenna at MFJ.

Suggestions for MFJ: offer a kit or accessory that would be make it easy to set the 1886 on a desk or table. Likewise a kit or accessory that would facilitate using the 1886 on a camera tripod seems like a good idea.

Additional note: The SWLing forum is a great place for discussing all things related to shortwave listening.

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Dan reviews the new Chameleon CHA RXL Pro Wideband Magnetic Loop Antenna

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Many thanks to SWLing Post contributor, Dan Robinson, for the following guest post and review:

Photo by Chameleon

The Chameleon CHA-RXL Pro: Improved Amp Board Raises the Game

by Dan Robinson

Back in 2021 I reviewed the CHA-RXL loop by Chameleon. This loop antenna is sold by major retailers such as DX Engineering, Gigaparts and Chameleon itself – the company is a well-known name in antennas and other equipment for the amateur radio world.

I compared the CHA-RXL to Wellbrook 1530 and W6LVP loops feeding into a four-position Delta antenna switcher, and then to a Raven 16 port multicoupler which maintains good steady gain.

My Wellbrook is mounted on a telescopic mast about 15 feet above ground level, with a rotor. The W6LVP (using LMR400 coax) is tripod-mounted with an overall height from ground of about 12 feet. It has special filters to prevent strong medium wave signals from bleeding into HF.

I have since added a UK-made loop (essentially a copy of a Wellbrook loop but smaller diameter and made of metal) combined with a W6LVP amp. This W6 amp does not have filtering to block strong mediumwave signals. In all, I have four loops into my Delta switcher, which feeds about two dozen receivers.

There is by the way quite robust discussion at https://groups.io/g/loopantennas about various loops, including the Chameleon. And this past July, Steve Ratzlaff posted news about the upgraded loop amp board which will ship with what is now the CHA RXL Pro, saying:

“Chameleon has completely redone their CHA RXL loop amp board from the previous poor-performing loop amp that I tested some time back, and sent me one of the new production boards to test. I’m happy to say it tests very well especially for LF sensitivity, and I can now give it my “seal of approval”. The new board is a version of the LZ1AQ loop amp.”

Photo by Chameleon

It turns out, according to an email from Don Sherman of Chameleon, that Steve is one of the engineers who helped design the new amp board for the CHA RXL Pro, and on the Loop Antenna group he provides a folder in which he placed previous test results with “new files of the new board (sweep of the new RXL Pro loop amp, and a picture of the new amp PCB).”

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Matt’s 2022 Portable Loop Antenna Shootout

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Many thanks to SWLing Post contributor, Matt Blaze, for the following guest post:

Matt’s 2022 Portable Loop Antenna Shootout

by Matt Blaze, WB2SRI

Followers of this blog may be familiar with my “shortwave radio shootouts” that I post from time to time. The idea is to compare how well different radios demodulate the exact same signal. Basically, I take a bunch of radios, hook them up to the same antenna via an RF distribution amplifier, tune the radios to some distant signal, and record the audio output from them simultaneously. Sometimes that kind of comparison can be more revealing of actual real-world performance than lab measurements or technical specifications.

The other day, I decided to do the same thing, but for antennas instead of radios. Essentially, I inverted the setup. Instead of hooking up different radios to the same antenna, I hooked up identical radios to different portable antennas and recorded them demodulating the same signals at the same time.

In this first of perhaps a series of these antenna shootouts, I wanted to compare three portable amplified magnetic loop antennas. When I say “portable” here, I mean broadband antennas that can pack reasonable compactly for travel and that can be set up and broken down easily for use “on location”, say on a picnic table or hotel balcony, or perhaps installed temporarily on a roof, without too much fuss.

The antennas are:

– The Wellbrook FLX1530LN with a 1 meter diameter loop of LMR400 coax. This is my “standard” portable antenna (I use a telescoping broom handle for the support; I wrote about it here as the “signal sweeper” last year). Excellent performance, but on the bulky side for travel. Performs well from LW through HF. Not cheap, at about USD 225 including shipping for the amplifier and power injector, but not including the loop, mounting hardware, or feedline.

– The Wellbrook FLX1530LN with a 0.5 meter diameter loop of RG142 (a stiff “aircraft grade” version of RG58 that holds it shape well at this size). I used some 1/2 inch PVC pipe as the vertical support. Because of the smaller diameter loop and thinner coax, it packs down to a much smaller and lighter package than the 1 meter LMR400 version.

– The K-180WLA, an inexpensive (about USD 60) 0.5 meter loop from China, sold on eBay and Amazon. The loop is steel wire (which can be wound down to a small diameter for transport), and the kit includes everything you need, including a rechargeable power injector. (However, the power injector uses a noisy voltage booster, so I substituted my own bias-T injector for these experiments). Ostensibly covers LW through VHF, but the low end coverage is, shall we say, somewhat aspirational, as you will see.

– I also recorded, for comparison, the built-in ferrite bar (for LW/MW) and whip antenna (for HF) of the receiver.

This is, of course, only a small sampling of portable loop antennas, both commercial and homebrew. But I wanted to start with what I had on hand and with what meets my own needs. (I omitted from consideration loops that require tuning, since I want to be able to install the antenna without needing access to it every time I change frequency).

For each signal captured, I oriented and positioned each antennas to maximize signal quality, taking care to move them away from each other and interfering metal objects. So you’re hearing (approximately) the best each antenna had to offer (on my roof under suboptimal band conditions).

The receivers I used were four Sangean ATS-909×2 portable LW/MW/SW/FM/Air radios. I believe this to be the best currently available (relatively inexpensive) portable shortwave receiver on the market. It has excellent performance (and is admirably resistant to overload and intermod when used with an active antenna). It lacks a sync mode, but that’s rarely implemented well on portable radios anyway. As a practical matter, it has a good line-level output jack, and I already happened to own four of them.

As in my other shootouts, for each signal, there are a total of five recordings: a monoaural recording of the audio from each of the four antennas, plus a narrated stereo recording comparing a reference (the 1M Wellbrook) on the Left channel with each of the other antennas in succession on the Right channel. The stereo recording is intended as a quick overview, but it will only make sense if you listen in stereo, preferably with good headphones. (You can switch the earcups to get a quick comparison as you listen.)

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