Author Archives: Jock Elliott

Qodosen DX-286 First Impressions

By Jock Elliott, KB2GOM

There was quite a bit of excitement in the ultralight radio community in 2024 when folks “discovered” the Qodosen DX-286 radio.

The very first version of this radio was the Qodosen SR-286. Its Big Trick was that it was based on the NXP TEF6686 DSP chip which is designed for car radio use and delivered impressive performance on AM (medium wave broadcast band), FM, and shortwave (it also receives LW; I have not tested that.). The SR-286 was later refined and became the DX-286, which late last year I bought. The two versions of the radio look virtually identical except for the model designation on the front panel.

The bottom line: I can, indeed, confirm the performance of the DX-286 is, as my Dad used to say, “hotter than a two-dollar pistol.”

While I don’t actually know much about the thermal properties of cheap handguns, I can say with authority that the DX-286 is very pleasing to own and operate.

The DX-286 is a small radio, measuring 5.28″L x 1.18″W x 2.99″H. The fit and finish, for the most part, are excellent. The front is studded with 23 buttons, a speaker grill/opening, and a digital display. On the left side is a port for plugging in an external antenna. On the right side, you will find a tuning knob that can be pushed in to change the tuning step and auto tuning, a volume adjustment wheel, a charging port, and a port for plugging in headphones.. On the back is a hatch for accessing the rechargeable 18650 battery and a flimsy-looking flip-out foot for propping the DX-286 at an angle. On the top of the radio is a fold-out telescoping metal antenna that measure about 19 inches long when fully extended.

The DX-286 comes in a neat foam-cushioned plastic case that includes an extensive user manual, a drawstring bag for protecting the DX-286 when it is out of the case, a charging cable and an optional extra battery.

From the DX-286 manual, here are the frequency ranges that the DX-286 can receive and the tuning steps are available.

Frequency Range/Tuning Step

FM:

64-108MHz (suitable for Russia/Eastern Europe)
76-95MHz (suitable for Japan),
76-108MHz (suitable for School)
87-108MHz (suitable for Europe, Oceania, Africa, Asia)
87.5-108MHz (suitable for China, Americas)

(Tuning step is 250kHz/200kHz/100 kHz/50kHz/30kHz/10kHz)

SW: 1711-27000kHz (Tuning step is 1kHz/5kHz)

MW:

522-1620kHz (Tuning step is 1kHz/9kHz)
520-1710kHz (Tuning step is 1kHz/10kHz)

LW: 144-519kHz (Tuning step is 1kHz/3kHz)

Note: the DX-286 does not receive SSB signals, doesn’t do synchronous detection, or receive NOAA weather radio or the air band.

One of the things I have discovered messing with radios over the years is that ergonomics matter. The first definition of ergonomics from the American Heritage Dictionary is: The applied science of equipment design, as for the workplace, intended to maximize productivity by reducing operator fatigue and discomfort.

Let me give you an example of how ergonomics applies to radios. The XHDATA D-220 is a very simple radio. It receives FM/MW/SW bands and that’s it. As such, it has a very simple set of controls: a tuning knob, an ON/OFF/VOLUME knob, and a slide for selecting bands . . . and all that is needed.

By contrast, the Qodosen DX-286 is an extremely sophisticated receiver that offers a ton of interesting options: switching amplifiers and attenuators on and off, selecting internal and external antennas, choosing bandwidths, tuning steps and much more, each depending on what band you are trying receive.

In my view, in an ideal universe, a radio as sophisticated as the DX-286 would have a knob (or switch) for every job on its front panel, but that would make the front panel huge. However, in a small radio as sophisticated as the DX-286, many of the buttons serve more than one function, and those functions may change depending on band. As a result, you will be richly rewarded by studying the manual, which can be downloaded here [PDF], to take full advantage of the many functions of the DX-286.

But here’s the really good news: you don’t need encyclopedic knowledge of the user’s manual to use and enjoy the DX-286. I have been listening with it for three weeks and have consulted the manual exactly twice: once to find out how to switch to an external antenna while receiving MW (press and hold the RDS button) and once more to find out how to switch between medium wave and shortwave (quick-press the AM button until you get the selection you want; FM has its own button). In short, you can take a very un-sophisticated approach to the DX-286 and still have a bunch of fun with it.

The performance of the DX-286 is impressive.

I habitually listen with headphones (that helps to compensates for a hearing deficit that hearing aids can’t correct). Cruising the medium wave broadcast band, I’ve been able to hear very faint medium wave stations that I could not detect with other radios in its size class.

In addition, the DX-286 is the only ultralight that I own that allows me to connect an external antenna through a hardwire connection to boost medium wave reception. It’s easy: while in MW mode, plug the external antenna into the external antenna socket and then use the RDS button to switch from internal to external antenna. One of my joys has been to “sneak up” on very faint MW stations in the early morning using the DX-286’s internal MW antenna, then switch to the Terk AM Advantage loop antenna (connected through a hardwire) to attempt to boost the signal sufficiently to hear (or deduce) a station ID.

FM reception seems similarly robust . . . although I must admit that I am by no means an expert FM DXer. One evening, while poking around the FM band, a faint station popped up. Wiggling the telescoping antenna around, I found that if lowered the antenna to a horizontal orientation, I could receive an entirely different FM station. Cool! The DX-286 has RDS to help in IDing FM stations, but I wasn’t using it at the time.

SW performance, in my view, is also remarkable.

One mid-morning I used the AUTO seek buttons to search for SW stations using the whip antenna and found 20. Plugging in an external 45-foot wire loop antenna and using the seek function again, the DX-286 found 38 stations, some of which were at the extreme edge of detectability.

There are a couple of additional items that deserve mention. First, it seems there is something going on with the audio/signal processing within the DX-286 that renders the audio more pleasant to listen to on a “rough copy” MW/SW signal than some of my other radios. I might be deceiving myself, but I don’t think so.

Second, the DX-286 is quiet to operate. Pushing various buttons and turning the knob results in little noise, and this preserves domestic tranquility when I’m doing my horizontal DXing with the Better Half trying to drift off to sleep next to me.

Now, if this were a trip to Santa’s Lap, improvements to the DX-286 I would like to see would include SSB operation, NOAA weather radio, the air band, and operation off ordinary AA batteries . . . but lack of those aren’t deal breakers.

In the end, I can happily use and recommend the DX-286 just as it is.

Finally, a neat anecdote involving the DX-286. One of my pals bought one in the fall. He checked into the Radio Monitoring Net, which I run Tuesday nights on a local 2 meter repeater.

“I’ve got an election story to tell you, and it involves radio,” he said.

“Like you, I watched the election results on TV Tuesday night, but with the sound off. Instead, I was using the Qodosen DX-286 to listen to results on radio direct from Atlanta and Philadelphia (he lives in upstate New York). I got the results for Georgia and Pennsylvania two hours ahead of the national news!”

I told my wife about this, and she asked, “What radio was he using?”

I bet you can figure out the rest of the story.

Click here to check out the Qodosen DX-286 at Amazon.com
(Please note: this is an affiliate link that supports the SWLing Post at no cost to you.)

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A File Worth Having: Bob’s guide to building an Electrically Small Resonant Loop Antenna for Mediumwave Reception

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Screenshot

This post is short and sweet.

If you click here–Electrically Small Resonant Loop Antenna for Mediumwave Reception (PDF)–you can download a copy of Bob Colegrove’s excellent paper on the Electrically Small Resonant Loop Antenna for Mediumwave Reception.

He has actually built this antenna; it works; and he uses it often. Perhaps you might want to build one for yourself. As an added bonus, Bob is an excellent writer (in my not-so-humble opinion). What’s not to like?

— Jock Elliott, KB2GOM

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The Great Gonzo Radio Experiment

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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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Here we go loop de loop . . . in which your humble correspondent tests a hypothesis

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By Jock Elliott, KB2GOM

It was this post by Alan — https://swling.com/blog/2024/11/bbc-rd-how-to-test-a-loop-antenna/ — that set me off. After downloading the BBC report on how to test a loop antenna, I noticed the following in it:

“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.”

Huh, I thought, “I wonder this would have any bearing on how I use my MFJ 1886 loop antenna?

So hooking the 1886 loop to an SDRplay RSPdx, here’s what the spectrum looks like on medium wave in vertical orientation with the 1886’s internal amp turned on:

And here’s what the medium wave spectrum looks like with the loop in horizontal orientation, amp on:

But what about shortwave reception? Here’s 31 meters in vertical orientation:

And here’s 31 meters with the loop in horizontal orientation:

Here’s 25 meters in vertical orientation:

Here’s 25 meters in horizontal orientation:

It looks to me, at the very least, the noise floor is lower . . . or I am in desperate need of a laxative?

For more about my adventures with the 1886 loop, check this — https://swling.com/blog/2022/10/testing-the-mfj-1886-receive-loop-antenna/ — and this — https://swling.com/blog/2023/01/saturday-morning-fun-fat-mw-dxing-with-the-mfj-1886/

My conclusions: I definitely don’t want the 1886 loop in horizontal orientation for medium wave DXing, but I think that the flat orientation might help for shortwave DXing.

What do you think?

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A Shining Moment for Ham Radio

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By Jock Elliott, KB2GOM

“Any sufficiently advanced technology is indistinguishable from magic.”

– Arthur C. Clarke

Shame on us: we take it for granted that someone can speak into a microphone miles away (perhaps thousands of miles), we can hear them, reply to them, share information and maybe even get someone some help.

It’s astonishing, but we accept it as commonplace. (Let me remind you: every time you fire up your mobile phone – smartphone or otherwise – you’re using a radio). And yet it has the potential for greatness.

I saw that greatness demonstrated by ham radio in the response to the devastation brought to Western North Carolina and Eastern Tennessee by Hurricane Helene. Torrential rains and high winds wiped out infrastructure – roads, bridges, dwellings, businesses, power lines, cell towers – isolating people and putting them in peril . . . and cutting off the affected areas off so thoroughly that people not far away had no idea how desperate conditions were. It was bad . . . really bad.

The morning after Helene ripped a hole in civilization in Eastern Tennessee and Western North Carolina, Dan Mark K2DMG dropped his callsign on the Mount Mitchell repeater (which is fortuitously located on the highest peak in the Eastern United States, giving it enormous reach) and asked if anyone needed help . . . and that began a saga that will likely be studied as an example of radio emergency response for years to come. For hours and then days, Dan – who had never before been a net control – passed health and welfare messages, summoned help for people, and much, much more. Others listened to Dan’s radio traffic and used it to direct help to those who needed it and to find roads that were open.

In the heart of the affected area, Thomas Witherspoon K4SWL (SWLing Post’s Maximum Leader) also used ham radio to summon help for others and provide community communications.

But these few words do very poor service to what really happened. So I would heartily suggest, recommend, even implore you to listen to the following videos and podcast.

Ham Radio Workbench Podcast:

https://www.hamradioworkbench.com/podcast/hrwb-221-thomas-witherspoon-k4swl-on-hurricane-helene-and-emergency-prep

Ham Radio Crash Course:

KM4ACK:

I think they will boost your appreciation of the potential of ham radio to do good. I know they inspired me.

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Responding to “The Colegrove Inspiration”

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By Jock Elliott, KB2GOM

It was Bob Colegrove’s post — this one — that inspired me and set me on this path.

Medium wave broadcast band DXing (MWBCB) has a certain fascination for me, but I am poor at it. Oh sure, I have read the advice: map the band at noon, then again at midnight, and you’ll have a better idea of what’s unusual as you are tuning around. But I have never gotten around to doing the mapping, so my DXing skills are lousy at best.

When Bob asked, “What’s your favorite corner of the dial?”, he also mentioned the challenge hunting below 600 kHz. The implication: whatever is in that section of the band, there are probably not a lot of stations, and they are hard to hear. So, I reasoned in my tiny little brain: “If I hear anything down there, it’s likely to be DX.”

So I tried it, firing up the Grundig Satellit 800 hooked to an MFJ 1886 loop during the daylight hours. With exception of WROW, 590, in nearby Albany, NY, blasting oldies with 5,000 watts, I found nothing . . . and I do mean nothing: nada, diddly, bupkas, cipher, rien . . . dead band . . . deader than old Jacob Marley. I try it again in the early evening with three different radios with exactly the same results. Nuts.

But then I try again with the Satellit 800/1886 combo at a little after 0900Z and take Bob’s advice about using single sideband. Aha! Carriers 540, 550, and 560. Then at 570, a weird mixture: religious programming in American English over male and female voices in Spanish with time ticks and tones in the background. Is there a time station on this frequency or is it some sort of bleed-over?

On Tuesday evenings I run the Radio Monitoring Net on the 146.94 repeater. During the net, I mentioned the unusual signal I had heard on 570, and W2SRA, an expert DXer, responded with the opinion that this was likely a religious station on Long Island, NY, intermixed with a station known as The Clock from Cuba.

Here’s what Wikipedia has to say about it: Radio Reloj (Spanish for Radio Clock) is a government-owned Spanish-language radio station in Cuba . . . The station is noted for the sound of a ticking clock in the background, with its hosts announcing the time, every minute of broadcast.

I checked the distance from Troy, NY, to Santa Clara, Cuba where the 570 AM station is located; it’s 1449 miles. Wow! According to Wikipedia, the AM transmit power is 50,000 watts

Then I remember that William, KR8L, mentioned that he likes searching above 1620 (another less populated region of the band), so I give that a try. At 1690, I hear oldies, followed by ads for Southern Maryland. The station finally ID’s as WPTX, 1,000 watts nighttime power, in California, MD, a distance of 339 miles. Yes!!

Thanks, Bob and William, for turning me on to some more radio fun!

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From the Archives: When the fertilizer hits the fan radio kit

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By Jock Elliott, KB2GOM

Murphy’s Law: If anything can go wrong, it will.

1^st corollary: Even if anything can’t go wrong, it still will.

2^nd corollary: It will go wrong in the worst possible place at the worst possible time.

Most devastating corollary: Murphy was an optimist.

“It’s tough to make predictions, especially about the future.” – Yogi Berra

The Better Half thinks I am sick, and maybe she is right, but I am unrepentant: I like disaster movies and books. True stories are better than fiction, but I like both, and I am curious about how people, real or imagined, get through whatever Horrible Event faces them.

As I have written before–here, here, and here–that when bad stuff happens, radio can be a really useful tool.

It was a comment from a reader – Rob, W4ZNG – that got me thinking some more about this. He mentioned enduring three weeks without electricity on the Mississippi Gulf Coast as a result of Katrina. So we had a phone conversation about: What do you want in your radio kit bag when faced with a longer duration, more severe regional or national emergency?

Here’s some of the stuff we agreed upon.

Gathering Information

At the most basic level, you want a radio capable of receiving local AM or FM broadcasters, and it would be good to know ahead of time which local stations have local news staffs that can broadcast useful in formation in times of crisis. In addition, if you live in the US or Canada, I absolutely recommend the ability to receive NOAA weather radio. The ability to run off batteries is critical, in case the mains power is out. In addition, a generous supply of batteries, or a means to recharge batteries is in order. If you decide to go with recharging batteries, you need to think about your options now, not when the lights go out.

In Rob’s case, during Katrina, all of the local broadcasters were wiped out. There was a local low-power FM broadcaster who got permission to increase power to 1,000 watts and was broadcasting where to get food and water. There was a New Orleans AM station that was on the air, but all of its coverage was “New Orleans-centric.” After a few days, some local FM broadcaster, working together, cobbled together a station that they put on the air and began broadcasting news. Rob also began DXing AM stations at night to get additional news.

We agreed that shortwave broadcasters were not likely to be very useful in most cases, but a shortwave radio with the ability to hear ham radio single sideband networks might well be.

To scan, or not to scan, that is the question

Another potential source of information are local public agency radio transmissions in the VHF and UHF ranges that could be heard with a scanner. But – and this is a very big but – that depends a lot on whether your local government (first responders, etc.) transmissions are encrypted. You need to check a source like https://www.radioreference.com/db/ to see if Public Safety transmissions in your area are encrypted. If they are, you will be unable to decipher them, no matter what equipment you own. However, an inexpensive analog-only scanner may prove very useful for listening to ham transmissions VHF and UHF (2 meters and 440 primarily) as well as FRS and GMRS.

If your local Public Safety radio systems are not encrypted, the RR database will give the details of the radio systems used by those agencies, and that in turn will determine the level of sophistication of scanner that will be required to hear their transmission.

The Radio Reference database also includes a listing of national radio frequencies including a list of federal disaster frequencies such as might be used by FEMA. In addition, I have found that the folks at the Radio Reference forum are generous with their time and expertise: https://forums.radioreference.com/ . If all this sounds a bit daunting, there are scanners that have built-in databases of all available frequencies and radio systems, and all you need to do is put in your zip code and select which services you want to hear. I own one, they work well, but they are expensive.

Summoning Help

Assuming that the power is out, your cell phone may or may not work (during Hurricane Katrina, some people found that they could not make voice phone calls, but text messages would go through).

If the cell phones are not working, two-way radio may be useful to summon help and gather information. Again, some research on your part is in order. Perhaps there are 2-meter or 440 ham repeaters in your area with backup power, or maybe there is a robust GMRS repeater system. If so, get your ham or GMRS license and start participating! (It was his experience during Hurricane Katrina that prompted Rob to get his ham license, and when Hurricane Zeta hit, he was glad he had it.)

FRS bubble-pack radios are good for staying in touch while getting around the immediate neighborhood. It’s also good to have a few spares to hand to neighbors if the need arises. Often on sale (especially after Christmas) in multi-packs for less than $10 each.

Rob notes that great strides have been made in hardening cell phone towers since Katrina. When Hurricane Harvey clobbered Houston in 2017, the cell net stayed up. Even so, it would be prudent not to count on it!

The Bottom Line

At a bare minimum the ability to receive your local AM and FM broadcasters is essential, and NOAA weather radio is also very useful. At the next step up, depending upon your local situation, a scanner may help you to gather information. In addition, the ability to monitor ham transmissions may also add to your information gathering abilities. Finally, having a ham license and the ability to transmit on ham frequencies may be very valuable in a widespread or long-duration emergency.