Category Archives: Guest Posts

How Jake configures SDR# to listen to Encore classical music

Many thanks to SWLing Post contributor, Jake Brodsky (AB3A), who shares the following guest post:

How I Listen to Encore on Radio Tumbril

Listening to Classical music on shortwave is a challenge. It has loud and soft parts to the music. There may be selective fading. It isn’t a simple thing.

Also, configuring a software defined radio such as the highly configurable SDR# is not trivial. Note to readers: SDR# has been updated a lot recently and the noise reduction features are vastly improved. Kudos to Youssef Touil for all the hard work on this software. He continues to impress me with every update.

So I have some suggestions for those who are interested in listening:

First, get a decent set of over-the-ear headphones. Don’t rely on laptop speakers. They’re usually not designed for audio fidelity.

Set the radio for DSB reception with Lock Carrier and Anti-Fading checked. I also set the bandwidth to cover about 11 kHz or thereabouts.

On the Audio tab I uncheck the Filter Audio option. I’m going to rely on IF filtering to do my work for me.

Next, find an empty channel on the band where you will be listening to the program. Enable the IF Noise Reduction feature, set it to HiFi, and then set the threshold so that the noise floor is reasonably low. If you set the threshold too high, you’ll lose the higher frequency audio and there will be artifacts from the noise floor that I find unpleasant. A little bit of noise reduction is good, but more is not better.

I also enable the IF Filter/notch processing window to handle any stray birdies from switching mode power supplies. However, if not needed, I turn that feature off.

I turn off the AGC. And then I set the volume level to something reasonable, not too loud, not too soft, but just barely able to hear the noise floor.

Then I tune in the program. I was listening to the Sunday Evening (Monday 0200 UTC) broadcast from WRMI on 5950 kHz. There was some fading going back and forth. However, I took the atmospherics in stride, as if it were part of the experience. The broadcast from this evening
ended with the Pastoral Symphony from Beethoven. There were a few fades and there were a few swells, all due to atmospherics as the signal faded to the noise floor and emerged from it. But there was very little distortion. (thanks to the excellent engineers at WRMI).

The experience was actually sublime.

This is why I listen to shortwave broadcasts.

73,

Jake Brodsky, Amateur Radio Station AB3A

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Giuseppe Demonstrates his homemade “Minimal Long-Distance Dipole”

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

Dear Thomas and Friends of the SWLing Post,

I’m Giuseppe Morlè from Formia, central Italy on the Tyrrhenian Sea.

This time I want to show you 2 QRP connections made with minimal antenna over long distance and very few watts of power…

The antenna is a simple dipole, 5 meters per arm, 1/4 wave for 20 meters, on a bnc / banana socket directly on the Icom 705. You’ll see that the ROS is really optimal.

I wanted to experience this very simple antenna, easy to prepare in this location surrounded by greenery, Monte Orlando Park in Gaeta on my favorite DX bench;
this location is at 120 meters above sea level and facing south / west following the long path. A suitable place for the extreme right made especially for a receiver like the Icom 705– fantastic modulation and without any kind of noise.

In the first video the contact with VK2GJC, Greg from Australia who struggles a little to listen to me but immediately understands my name. As you can hear Greg’s voice is without any imperfection even if his signal is not that high:

In the second video, another link with Australia, VK5AVB, Tony from Kangaroo Island.
Tony had a hard time understanding my name but with the help of Nicola, IU5EYV from Tuscany, in pure Ham Spirit, he finally managed to log me:

As you can see, even with very minimal antennas hoisted on nearby trees, not even high from the ground, you can listen and contact over long distances … that’s why I love this place so much!

Thanks to you all, a cordial greeting from Italy.

Many thanks, once again, Giuseppe for showing us just how much fun we can have by building our own antennas and hopping on the air with very little power. I must say: you certainly play radio in a beautiful part of the world! Thank you!

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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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Guest commentary: Nothing is so constant as change

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Many thanks to SWLing Post contributor, Jerome van der Linden, who shares the following guest post:

Nothing is so constant as change

by Jerome van der Linden

Those of us who have had an interest in broadcasting over many years realize pretty soon that technology is constantly changing. The following relates to the situation where I live in Australia, but I suspect similar things are occurring in other parts of the world, and serve as a constant reminder that we live in a world of change.

When we were in our teens, we had radios that would tune AM and one or more shortwave bands. Hence many of us first heard interstate medium wave stations, and realised that signals there travelled further during darkness hours. Then we switched to SW1 or SW2 and often heard nothing. But persistence paid off and soon we were listening to stations that were in other countries! And when we connected a long wire to the antenna terminal signals improved dramatically. Wasn’t that amazing?

Somewhere in the 70s (I think) our TV stations brought in colour and that too was an amazing change to experience.

Then – somewhat belatedly for us in Australia – FM radio came along and gee the quality of the audio was outstanding! Even my late father was surprised by the clarity with which he could now listen to classical music on our nationwide dedicated ABC Classic FM station. FM also brought with it the introduction of “Community Radio” stations and in more recent years many other types of broadcasters.

Satellite TV came to us in the form of Foxtel: carrying so many different channels it was bewildering. When I realized that the events of 9-11 were telecast live on BBC World (and others), I too decided we should have Foxtel, as I have always been a “news nerd”.

By the late 1990s – having seen a hey day in probably the 60s and 70s – shortwave listening was rapidly becoming a thing of the past, and only hobbyists listened to SW: I remember being asked by another passenger when I was on a South Pacific cruise, what was that I was listening with out on deck? Was it some kind of computer? No, it was just a Sony SW55, and I was listening to Radio Australia.

Then, probably 5 years ago in Australia DAB+ radio was introduced, and whereas we previously had a choice of perhaps 10 to 15 AM & FM radio stations to tune to, suddenly we had a choice of these same stations on DAB radio (in major cities only), PLUS another 10 or 15! We have a phenomenal choice of what to listen to. From a technical view it was amazing to think that all the signals were coming from only one or two transmitters. For those of us with some technical interest it was for a while inconceivable that each station would not have its own transmitter.

Meanwhile, our TV systems have also become digitized in the last couple of years. Not just do we have perhaps three different channels for each commercial network, so 3 commercial networks are now providing probably 9 different programs. On top of that the Government broadcasters (ABC & SBS) have provided not just at least 3 TV channels each, but each of their numerous radio services is now also available on every TV set (eg BBC World Service is available 24/7).

About the same time, with higher internet speeds (ie better data transfers) being available, TV services and radio services are increasingly being streamed into our homes and to our mobile devices, with radio Apps promising they’re “free”, when in fact they do incur a data transfer impact/cost in whatever Internet plan one may have available. Many of the older generation probably don’t even realize what streaming video or sound means, but I think the younger generation is catching on.

Now, to my horror, my favourite DAB music station (“Buddha”) has been making announcements on air saying that the DAB service will be terminated from September 1st, and if I want to continue listening, I must tune in using that Company’s own “LiSTNR” app! Does this mean that listening to what comes over the ether will be a thing of the past? Will we be obliged to pay $x per annum to use a company’s streaming app just to be able to listen to their programs? Whatever is the world coming to?

Our country is, I suspect, very well catered for in terms of media services, and I wonder if we’ve done that too well. I also fear though, that those of us trying to push for reintroduction of shortwave services for remote Northern Territory areas (where streaming apps are a non sense), and for Australia to again broadcast into Pacific territories, may be fighting an uphill battle.

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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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Guest Post: Dan’s letter concerning the new Elite Satellit

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Many thanks to SWLing Post contributor, Dan Robinson, who publishes the following guest post:

Letter to Eton: Cutting Corners on Elite Satellit Won’t Succeed

by Dan Robinson

As SWLing.com readers will recall, weeks before Eton shipped the first group of Elite Satellit receivers I published a commentary that asked a key question: would Eton be able to meet the higher standards of the listening community in 2022 when it comes to new advanced portables?

Unfortunately, we all see what the answer to that question was. Eton was forced to recall Elite Satellit radios that had been shipped to major resellers such as Universal Radio, Ham Radio Outlet, and others as defects became all too apparent.

A radio that had been on its way to me for review was among those recalled. But I recently was able to examine a unit that a friend in the Washington, DC area purchased. What I found I am putting in this commentary as a letter to Eton.

If the company takes these points seriously, I think there is still hope that the Elite Satellit can join the ranks of respectable multi-band portables – after Eton has gone back to the drawing board so to speak. However, if Eton continues to cut corners with this receiver, its future is not bright:

Letter to Eton on the Elite Satellit

Dear Eton,

MUTING WHILE TUNING

As many who purchased or tested the Elite Satellit have remarked, the fact that you decided to release a radio with this issue is beyond comprehension. Tuning on the Elite Satellit is, tragically, an uncomfortable and frustrating experience. This needs to be corrected/fixed – you only need to take a look at Tecsun receivers such as the H-501 or PL-990x to know what needs to be done.

POORLY-IMPLEMENTED PASSBAND TUNING

Perhaps even more puzzling than muting, the Elite Satellit I tested had an even more mind-boggling issue. Passband tuning should function to adjust the signal pitch without changing the audio frequency. On the radio I tested, PBT was actually TUNING and changing the frequency. Using PBT on this radio was virtually no different from tuning in SSB, with injected tones heard, until a zero beat was achieved. All you had to do was take a look at a E1 receiver, or any other receiver with well-implemented PBT to understand how real PBT is supposed to function.

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Small Unidirectional Loop Antenna (SULA) Part 2: Construction Notes

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Many thanks to SWLing Post contributor extraordinaire, 13dka, who brings us Part Two of a three part series about the new SULA homebrew antenna project. This first article describes this affordable antenna and demonstrates its unique reception properties. This second article focuses on construction notes. The third and final article will essentially be a Q&A about the SULA antenna. All articles will eventually link to each other once published.

This wideband unidirectional antenna is an outstanding and innovative development for the portable DXer. I love the fact that it came to fruition via a collaboration between Grayhat and 13dka: two amazing gents and radio ambassadors on our SWLing.net discussion board and here on the SWLing Post. So many thanks to both of them!

Please enjoy and share Part 2:

Part 2: SULA Construction notes

by 13dka

The drawing [above] has all you need to know. You basically need to put up a symmetrical wire diamond starting with a balun at the one end and terminating in a resistor at the other end of the horizontal boom, the sides are supposed to be 76cm/29.92″ long so you need to make yourself some…

Support structure:

I used 0.63″/1.6cm square plastic square tubing/cable duct profiles from the home improvement market to make the support structure. You can use anything non-conductive for that of course, broom sticks, lathes… The plastic profiles I used had the advantage of being in the house and easy to work on with a Dremel-style tool and everything can be assembled using the same self-tapping screws without even drilling. The profiles are held together with 2 screws, for transport I unscrew one of them and put that into an extra “parking” screw hole on the side, then I can collapse the cross for easy fit into the trunk, a rucksack etc.

These profiles are available in different diameters that fit into each other like a telescoping whip. This is useful to make the support structure variable for experiments and to control the loop shape and tension on the wire. The booms end up at 1.075m each, the profiles come in 1m length, so that’s 4 short pieces of the smaller size tube to extend the main booms by 37mm on each side

On the resistor end of the loop that smaller tube isn’t mounted in the “boom” tube but to the side of it in order to keep the wire running straight from the balun box on the other side.

Mast/mounting:

You can use anything non-conductive to bring it up to height. On second thought that is indeed bad news if you were planning on putting that up on your metal mast…and we have no data on what happens when you do it anyway. I don’t know if the smallest (4m) telescoping fiberglass poles would suffice for portable operation, but I’m a fan of just using the big lower segments of my 10m “HD” mast for the stiffness they give me (3 segments for the height, the 4th collapsed into in the base segment for easy rotation). Telescoping masts also give you easy control over…

Height:

The published patterns are for 3m/10′ feedpoint height over “average” ground. Increasing height further has no expectable advantage, instead it will deteriorate the favorable directional pattern of the loop. Flying it lower, or even a lot lower in windy weather on the other hand is causing a surprisingly moderate hit on performance.

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