DX Engineering was excited to catch up with VE2DX Electronics founder and longtime amateur radio operator Richard Desaulniers, Sr., VE2DX, at Dayton Hamvention 2024. Watch VE2DX run down the Quebec-based company’s lineup of TrueCIV Icom Transceiver Data Hubs, Remote Antenna Switches, Portable Two-Inch Meter Displays, and the Icom Digital Meter HDMI Display TrueCIV Interface available at DXEngineering.com.
Richard also highlights new VE2DX products that will be coming to DX Engineering in the weeks ahead, including band decoders, Bluetooth CAT interfaces, and EMI filters.
Here’s a quick look at what’s available now from VE2DX at DXEngineering.com.
This small electronic device (IM1-HDMI V2) connects Icom transceivers to any size HDMI flat panel monitor or TV for an amazing multi-function meter display. It simultaneously interfaces to a PC and multiple accessories via USB, Bluetooth, and CI-V.
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VE2DX TrueCIV 5-Port Icom Interface Data Hubs
These data hubs connect the interfaced transceiver’s CI-V data stream to multiple accessories simultaneously. VE2DX’s TrueCIV creates a new CI-V TTL standard that is unmatched for CI-V signal performance, signal integrity, maximum link length, and RFI prevention. These hubs deliver perfect CI-V data to many types of tuners, band pass filters, and more.
The hubs below feature CI-V over Bluetooth and a 5-port hub that connects the interfaced transceiver’s CI-V data stream to multiple accessories simultaneously.
VE2DX’s IM1-4BTPLUS V2 Icom Digital Meter and TrueCIV Interface is a high-quality two-inch meter display and TrueCIV version 2 data hub for most Icom transceivers. This unique mini-screen device can show two bar graph meters or two needle meter displays, as selected with two front panel buttons, as well as other transceiver status indicators. This specially programmed VE2DX device ingeniously samples Icom transceiver CI-V data to display available information in multiple formats, depending upon radio model. The meter includes CT17B-MICRO v2 internal 3-port hub with TrueCIV. The IM1-4BTTUFF V2 TUFF METER model is waterproof for outdoor operation.
VE2DX SO2R 2X6 Remote Antenna Switches provide selection of any six antennas for connection to two radios, covering the frequency range of 1.8 to 54 MHz. All control signals are RFI filtered as are all VE2DX printed circuit boards with shielding on both sides. Each SO-239 antenna port features five relays to achieve a design with over 80db port isolation and full legal-limit power handling. Switches are available in 24VDC or 12VDC relay versions.
This weekend saw a mix of various Amateur Radio activities. Getting on HF was not predominant, although I did get on Sunday morning for a bit and worked a few POTA activations. Brave souls, those activators, because all weekend long, the Space Weather Live app was VERY active. It seemed like every time I turned around I was getting a notification of a new solar flare or a "minor" radio blackout. On Facebook, more than one activator commented about the crummy band conditions and the noticeably fewer stations that they were able to log.
Saturday morning saw our monthly VE Session. We had two candidates, one of whom upgraded to Amateur Extra. Our other candidate got his Technician class license and missed becoming a General by only three wrong answers. He got 12 wrong and you're allowed up to 9. So close! The bright side is that he saw the exam, he has an idea now of what's on it and he should have a good idea where he's comfortable with his knowledge and where he needs to study more. I predict he'll be a General class Ham within a month or two.
On Sunday morning, I made the additional "modification" to my drive on mast holder. The lid hinges that I ordered through Amazon were delivered on Thursday. They did the trick to a "T" - or maybe I should say to an "L". HI!
The hinges lock in and brace the two boards at a 90 degree angle, just as I need them to. In fact, this configuration is so stable that in a pinch, any heavy weight will suffice, such as a heavy rock, or a cinder block, or a sand bag or something like that It's an ideal drive on mast holder, and while a vehicle is certainly preferred, it's not absolutely necessary. Conceivably, with a heavy enough weight, I could use this in the field on Field Day would no longer have to mess with the PVC holder that uses the tent pegs and CamJams. That would be a time saver! The only prerequisite is that I'd have to find a location flat enough to place this on so that it's not leaning in any one direction too much.
BTW, before you ask, the 4 holes in the horizontal board are there to give the protruding U-Bolt threads and the nuts the space they need so that when collapsed, this contraption can lay totally flat and not wedged.
Other than that, the weekend was occupied with the normal weekend chores and duties. Hope you had a good weekend and I'm looking forward to the Skeeter Hunt next Sunday!
Tonight we have a CERT training session with the NorthStar helicopter. NorthStar is the helicopter owned and utilized by the NJ State Police for the northern half of New Jersey. (SouthStar covers the southern half of the state). It is used primarily for transporting medivac patients to wherever they need to go depending on the circumstances and extent of their injuries. The session tonight will certify that we've been properly trained on procedures and safety requirements, so that we can approach the helicopter and assist with loading and unloading victims should it ever become =necessary.
Here is a summary of the news trending This Week in Amateur Radio. This week's edition is anchored by Chris Perrine, KB2FAF, Dave Wilson, WA2HOY, Rich Lawrence, KB2MOB, Don Hulick, K2ATJ, Joshua Marler, AA4WX, Marvin Turner, W0MET, Eric Zittel, KD2RJX, Will Rogers, K5WLR, Denny Haight, NZ8D, George Bowen, W2XBS, and Jessica Bowen, KC2VWX.
My, how time flies. This is a post I have been meaning to write for nearly 3 years now. Back in late 2018, after a search for a small portable SW receiver, I purchased a C Crane Skywave SSB. It had a lot of the things I wanted in a portable radio and, at the time, I felt that it offered a lot for a receiver of it’s diminutive size.
Then I became aware of an even smaller receiver called the Belka-DX. Designed and manufactured by Alex EU1ME in Belarus, this positively tiny radio used SDR technology and, judging by the reviews I was reading and videos I was watching on YouTube, there was no other receiver it’s size that felt and performed like a much larger communications receiver in the way that this one apparently did. It all seemed very encouraging, so I went ahead and ordered one directly from Alex in Belarus. The first time I tried to order direct from his site, my bank denied the payment. I got on the phone to advise them that it was a legitimate charge, and they gave me a one hour window in which to put the transaction through again. I returned to the site, ordered the Belka-DX, and the order was accepted.
There are 3 ways I know of to purchase Belka receivers –
Directly from Alex EU1ME, in Belarus. Alex supplies 2 versions, with and without a built-in speaker. In order to accommodate the built-in speaker, that particular version has a slightly smaller battery. The version with the built-in speaker currently costs 475BYN, which at the exchange rate at the time of writing, is about US$145. As of Aug 9th 2024, Alex’s site carries the message that international shipping is currently unavailable. I notice that in the Q&A, Alex noted in July that he hopes to resume shipping to the US in about a month. This was the message he posted, on July 18th 2024 – “We do ship to the USA but at the moment we need to to undergo technical expert appraisal so that our Belarusian customs could allow export abroad. We hope to restart shipping in a month. Shipping cost to the USA is 13 USD.”
From Mobimax in Bulgaria. This is the same receiver, but with a larger speaker back that also has two small fold-out legs. This increases the depth of the Belka, but allows you to have a speaker as well as the larger 2500mAH battery. The markings for the input and output connections on the sides are etched into the metal. In addition, the LCD display is fitted with a screen protector into which are etched the words “HAM tactical RCVR”. Mobimax sell two different packages containing this receiver. The only difference is that the very slightly more expensive package includes a 3.5mm stereo to 3.5mm stereo cable, for plugging the IQ output of the Belka to your computer for use with SDR software. The version of the Belka that Mobimax supply is currently 227 Euros, which is about US$247. The package with the IQ cable is just a few Euros more.
There is an eBay seller in Bulgaria who sells the same version that Mobimax does, but for the (in my opinion) rather high price of US$350. The main reason I can see that buyers might go for this seller is the convenience and comfort factor of being able to pay with Paypal on a site they are familiar with.
A few weeks after ordering, a small box arrived from Belarus. In it was the Belka-DX wrapped in bubble wrap, and a small telescopic whip antenna of about 28.5″ in length. No documentation was included in the box, though it is available online. I didn’t take any pictures of it then, so here are some of it now, 3 years later.
In the above image, the backlight is on. In the next one, it is off. The backlight can be customized to be on all the time, off all the time, or to stay on for 12 seconds after any button is pushed or the tuning knob is turned. In the next photo, to the left of the BNC is a micro-USB connector that is used for charging the receiver. Underneath it is a red LED that lights when charging. To the right of the BNC antenna connector is the 3.5mm earphone jack. It is important that a stereo TRS jack is used here. A mono jack will short out one of the channels and can damage the audio IC –
At 82mm x 50mm x 20mm, this receiver is small!
I’m not sure if this is still true of the version that comes with the internal speaker direct from Alex, but the speaker holes in mine were slightly imperfect. It was evident that they had been drilled by hand. Not a big deal, but I thought it worth noting –
On the right side is the tuning encoder. It rotates smoothly with no click stops, for that “big receiver” smooth tuning feel. Also on the right side is a 3.5mm jack for the IQ output –
This was the second iteration of this receiver. The first one, named the Belka-DSP, covered 3.5-31 MHz. The Belka-DX covers 1.5-31 MHz. There is now a newer version, known simply as “Belka”, that has impressively continuous coverage from 0.1 MHz – 31MHz. Yes – 100KHz to 31MHz!
There are, by now, a number of quite detailed reviews of this series of receivers online. One such review, which gives a good overview of the capabilities of this pint-sized communications receiver, was written by Dave N9EWO. Since purchasing my Belka-DX almost 3 years ago, I have used it regularly. There are several features that I find very compelling, which distinguish it from many other shortwave portables –
There is no chuffing or soft-muting in between frequency steps. As a result, when on the smallest frequency step of 10Hz, the effect is of smooth, continuous tuning.
Unlike the CC Skywave SSB and, I believe, many other portables of it’s type, it is absolutely solid on SSB and CW receive. The carrier injection on my C Crane receiver was unsteady on strong signals, leading to chirping on CW, and similar frequency instability on SSB. For a short while, I owned a CountyComm GP-5 SSB, which was even more unsteady. The Belka-DX handles like a proper communications receiver in this regard, being rock steady on strong and weak signals alike.
The frequency display is accurate. As far as I can tell, it is accurate to better than 10-20Hz across the frequency range. Because of this, I can easily tune it to a frequency, and know that it is there. The Belka-DX employs a 0.5ppm TXCO and as a result, has a high level of frequency stability. My Skywave SSB only tunes in 1 KHz steps. To interpolate between those steps, you have to push a button to engage the fine tuning, but are not able to read the frequency accurately in between those 1 KHz points. For many users, this might not be an issue, but for those who listen out for weak beacons and other signals that are not on 1 KHz “channels”, the continuous tuning and accurate frequency readout on the Belka makes such monitoring much easier. A couple of years ago, I went on a 4 /12 month long campervan trip around 6 Western states. At the time, one of my interests was listening out for low-powered unlicensed HF beacons. Standing in the vast expanses of the desert with the little Belka-DX in my hand, hearing a weak low-powered CW beacon from hundreds of miles away was magical. These beacons are home-made affairs, and usually running somewhere between 30mW and a watt. Being able to dial in the precise frequency on a handheld receiver that is even sensitive with the set-top whip is a boon with such pursuits.
You can tailor the passband for each mode. With my C Crane Skywave, and I believe many other similar receivers, the adjustable filtering (if available) is audio filtering, and doesn’t occur in the RF stages. The Belka is an SDR, and the custom adjustable filtering is the equivalent of filtering in the RF or IF stages of a conventional superhet.
Two things that I wasn’t too keen on, and which have been amended in the 0.1-31MHz version –
In CW mode, the frequency display doesn’t indicate the operating frequency. For example, with a 700Hz sidetone pitch selected, if you want to receive a CW signal on 7030 KHz, you have to tune the receiver 700 Hz below that frequency i.e. to 7029.3 KHz. You do get used to it, but it would be nice to have it display the actual operating frequency in CW mode. In the newest version, the 0.1-31MHz version, I have read that the receiver displays the actual operating frequency in CW. If you’re concerned with being able to read out the exact frequency (if searching for weak beacons on non-standard frequencies, for example) you’ll still need to ensure that you tune to the correct sidetone frequency in order for the frequency readout to be accurate. Personally, I’d love a sidetone feature for this, but I doubt that too many others would consider it to be an essential feature in a receiver (as opposed to a transceiver).
When stepping through the memory channels, you cannot hear those channels as you cycle through them. In order to hear the selected channel, you have to press the appropriate button to select and load it. Thus, you cannot easily scan through a number of preset memory channels to listen for activity. As with 1 above, I this has been remedied in the newest version of the Belka.
The audio quality from the Belka-DX is excellent when used with earbuds. The internal speaker doesn’t do it justice, though it is very useful when taking the receiver on outings. Power from the audio amplifier is adequate for most applications, though when plugging an external speaker in, it helps to use one that is sensitive. Some people use powered speakers. I have two external speakers on the bench, both unpowered, that I use with it. The main one is an MFJ-281 ClearTone speaker. It is sensitive, and produces good volume. The audio response from the mylar cone is restricted, and what I would characterize as communications quality. Audio is clear and intelligible. The speaker appears to have a natural resonance at around 650-700Hz, which is useful for CW. For those times when I need a little more fidelity, such as when listening to strong SWBC stations, or hams on AM, I use an old and compact hi-fi speaker manufactured by Cambridge Soundworks. It was discarded by one of my neighbors, and appears to be a mid-range unit. It is not as sensitive as the MFJ ClearTone speaker, but the Belka will still provide enough drive in a small, quiet room, which perfectly describes the conditions in my shack.
The small size and slim dimensions of the Belka-DX make it ideal for traveling. When using it at home with an external antenna connected, the ergonomics and ease of use are much improved when mounted on some kind of stand. There are a number of stands available, as well as files for those who wish to 3D-print their own. I remembered a clamp I once bought, that was designed to hold a cellphone for attaching it to a tripod, for making videos. The Belka is not quite as wide as a cellphone, so I used a couple of pieces of dense foam to pad it out, and screwed it to a small tabletop tripod. It works quite well, and improves the ease of use drastically when listening at home. When mounted like this, it feels like a serious and very usable SWL set-up. In the various SWL groups on FB that I frequent, I often see questions from folk asking about receivers that are good for SWL’ing. Portables such as the Tecsun PL-880, along with other similar receivers are often recommended. I think that this Belka makes an excellent receiver for all-round shortwave listening. It is not available in as many outlets as the more traditional shortwave portables, which is why I think that it isn’t as popular in the SWL community as it should be. If you are listening mainly to AM broadcasts on shortwave, then many of the portables will most likely work well. If you do a lot of SSB and CW listening though, the Belka is a solid and, to my mind, preferable option.
In the following picture, my Belka is mounted on a mini tripod (an Ultrapod) and connected to the MFJ ClearTone speaker. Behind and underneath the Belka, you can just see an Altoids tin which contains a high pass filter with a cut-off at about 2700 KHz. It was designed to prevent overload from strong local AM broadcast stations. More on that later in this post.
The Belka-DX is surprisingly sensitive when listening outdoors with the included telescopic whip. It does need a counterpoise, or the received signal strength suffers greatly. If you are holding the receiver, then your body acts as the counterpoise. If you are listening on earbuds or headphones, then the headphone cord acts as a counterpoise. If the receiver is sitting on a surface and using the internal speaker, then you’ll need to connect a counterpoise wire somehow. At home, it works really well when connected to my outdoor antena, which is a doublet at 47 feet, cut roughly for 40M, fed with 300 ohm twinlead, and matched to coax at the entrance to the shack, with a balun and Elecraft T1 tuner. I tune the T1 by squirting RF into it on the nearest amateur band. If you are using your outdoor antenna for listening only, then a simpler arrangement would suffice. This just happens to be the one antenna I also use for my ham exploits.
I live in a densely populated urban area, within a few miles of several medium power (5KW) AM broadcast stations. They often break through when I am using the external antenna with receivers that don’t have narrow filtering on the antenna input. My Belka-DX experiences strong AM breakthrough when used on the external antenna at all frequencies up to 4530 KHz. The moment I tune above 4530 – even by a single 10Hz step, the breakthrough stops instantly, suggesting that a different bandpass filter is switched in at the point. According to the manufacturer-supplied block diagram of the first version of Belka, known as the Belka-DSP, the input bandpass filters are from 3.5-7.5MHz, 7.5-15MHz, and 15-30MHz. The block diagram can be seen on this page by Fernando Duarte. I assume that for the Belka-DX, with it’s extended coverage down to 1.5 MHz, one of the bandpass filter crossover points is at 4530 KHz, the point above which all AM BC band breakthrough stops.
To solve this problem of breakthrough, I resorted to a little high pass filter that I have used successfully with other receiver projects. It’s a high pass filter that was designed by David WA7JHZ, details of which were given in K4SWL’s very wonderful and informative SWLing Post blog. You can see it here. David built his with molded chokes. I built versions with both molded chokes and toroids, and compared the response curves.
Trusty Altoids tins to the rescue. Here’s the version built with molded chokes, purchased from Tayda Electronics. The chokes are mounted vertically, and are a little hard to see in this image –
The small holes in the base of the tin were left over from a previous project that didn’t work out.
Then I built another high pass filter with toroids instead of molded chokes. I figured the toroids should have slightly higher Q and would present a better response curve. All 4 inductors were wound on T37-6 toroid cores with 26 AWG wire. The 2.7µH inductors had 30 turns and the 1µH ones 18 turns. The wires supported them about 4 or 5mm above the ground plane of the Altoid tin –
Dang, after all these years, Altoids tins still make very serviceable and cheap enclosures for small projects!
These filters were designed for input and output impedances of 50Ω. My one external HF antenna is a 40M doublet fed with 300Ω twinlead, and matched to 50Ω coax with a 1:1 balun and Elecraft T1 tuner. As mentioned previously, I briefly transmit a small amount of power on the nearest ham band to where I want to listen, to tune the T1. A manual tuner could be used here instead, and tuned for maximum noise. For listening, this is not too critical a procedure, and a single tune will cover the receiver for listening on a wide range of frequencies. The antenna input of the Belka is matched for the high impedance of the supplied short telescopic whip, and not for a 50Ω antenna. Nevertheless, I went ahead and plugged both versions of this HPF in between the antenna and the receiver, and they both served to completely eradicate every single trace of AM BC band breakthrough.
Using a NanoVNA, I measured the response curve of both filters from 1.5 MHz to 30MHz. Here’s the curve for the filter built with molded chokes –
FREQUENCY (MHz)
INSERTION LOSS (dB)
30
0
20
0.1
15
0.25
10
0.5
3.7
1
3
3
1.7 (1700 KHz)
41
1.5 (1500 KHz)
49
The 3dB cutoff point of this filter was actually 3 MHz, and the insertion loss small, with a virtually flat response from the 80M band up to the top of the 10M band. Here’s a close-up of the response between 1.5 MHz and 4 MHz –
The insertion loss of the toroid filter in the passband was a little lower, For all practical purposes though, there would be no discernible difference between the two filters. If you hate winding toroids, then by all means, build this filter with molded chokes, and it will kill your AM BC band breakthrough just as effectively as if you’d built it with toroids. Here’s the response curve of the toroid version from 1500 KHz to 30 MHz –
And from 1500 KHz to 4 MHz, giving a closer look at the area around the the 3dB cutoff point –
FREQUENCY (MHz)
INSERTION LOSS (dB)
30
0
20
0.04
15
0.12
10
0.25
3.7
0.82
2.8
3
1.7 (1700 KHz)
40
1.5 (1500 KHz)
48
There are quite a few internally generated birdies throughout the whole coverage range. However, the majority of them are only audible with no antenna connected, and are masked by band noise. The others, although audible over the band noise, are not troublesome. For a receiver this compact, and with this overall level of performance, it’s a small price to pay. I rarely noticed them during normal use. It would be nice for the end-user to have a way to update the firmware, though the extended coverage down to 100KHz that the new (V3) Belka enjoys required a hardware upgrade in the form of an extra bandpass filter.
For a more complete description of the improvements made with the newest Belka version, see 13dka’s guest post on Thomas K4SWl’s excellent SWLing Post blog. In short, the Belka is a fantastic general coverage shortwave receiver. It performs and handles like much larger tabletop communications receivers. It is so small that it can be carried anywhere with great ease, making the decision to do a little SWL’ing while on a hike, a walk, or any trip, a no-brainer. You can do a lot of serious shortwave listening with this receiver. Ordering direct from Alex in Belarus offers by far the lowest price and is, in my opinion, the way to go. When I think of my first communications receiver, an old, huge and very heavy British military R107 boat anchor, it is amazing to think that this light and svelte pocketable Belka-DX handily runs circles around it. An SWL can positively rule the shortwaves with this tiny and light miracle of wireless!
There are many other, far more comprehensive reviews on this receiver, but I have been wanting to sing the praises of the Belka (which is Russian for squirrel) for a long time now. I needed to get this out.
My, how time flies. This is a post I have been meaning to write for nearly 3 years now. Back in late 2018, after a search for a small portable SW receiver, I purchased a C Crane Skywave SSB. It had a lot of the things I wanted in a portable radio and, at the time, I felt that it offered a lot for a receiver of it’s diminutive size.
Then I became aware of an even smaller receiver called the Belka-DX. Designed and manufactured by Alex EU1ME in Belarus, this positively tiny radio used SDR technology and, judging by the reviews I was reading and videos I was watching on YouTube, there was no other receiver it’s size that felt and performed like a much larger communications receiver in the way that this one apparently did. It all seemed very encouraging, so I went ahead and ordered one directly from Alex in Belarus. The first time I tried to order direct from his site, my bank denied the payment. I got on the phone to advise them that it was a legitimate charge, and they gave me a one hour window in which to put the transaction through again. I returned to the site, ordered the Belka-DX, and the order was accepted.
There are 3 ways I know of to purchase Belka receivers –
Directly from Alex EU1ME, in Belarus. Alex supplies 2 versions, with and without a built-in speaker. In order to accommodate the built-in speaker, that particular version has a slightly smaller battery. The version with the built-in speaker currently costs 475BYN, which at the exchange rate at the time of writing, is about US$145. As of Aug 9th 2024, Alex’s site carries the message that international shipping is currently unavailable. I notice that in the Q&A, Alex noted in July that he hopes to resume shipping to the US in about a month. This was the message he posted, on July 18th 2024 – “We do ship to the USA but at the moment we need to to undergo technical expert appraisal so that our Belarusian customs could allow export abroad. We hope to restart shipping in a month. Shipping cost to the USA is 13 USD.”
From Mobimax in Bulgaria. This is the same receiver, but with a larger speaker back that also has two small fold-out legs. This increases the depth of the Belka, but allows you to have a speaker as well as the larger 2500mAH battery. The markings for the input and output connections on the sides are etched into the metal. In addition, the LCD display is fitted with a screen protector into which are etched the words “HAM tactical RCVR”. Mobimax sell two different packages containing this receiver. The only difference is that the very slightly more expensive package includes a 3.5mm stereo to 3.5mm stereo cable, for plugging the IQ output of the Belka to your computer for use with SDR software. The version of the Belka that Mobimax supply is currently 227 Euros, which is about US$247. The package with the IQ cable is just a few Euros more.
There is an eBay seller in Bulgaria who sells the same version that Mobimax does, but for the (in my opinion) rather high price of US$350. The main reason I can see that buyers might go for this seller is the convenience and comfort factor of being able to pay with Paypal on a site they are familiar with.
A few weeks after ordering, a small box arrived from Belarus. In it was the Belka-DX wrapped in bubble wrap, and a small telescopic whip antenna of about 28.5″ in length. No documentation was included in the box, though it is available online. I didn’t take any pictures of it then, so here are some of it now, 3 years later.
In the above image, the backlight is on. In the next one, it is off. The backlight can be customized to be on all the time, off all the time, or to stay on for 12 seconds after any button is pushed or the tuning knob is turned. In the next photo, to the left of the BNC is a micro-USB connector that is used for charging the receiver. Underneath it is a red LED that lights when charging. To the right of the BNC antenna connector is the 3.5mm earphone jack. It is important that a stereo TRS jack is used here. A mono jack will short out one of the channels and can damage the audio IC –
At 82mm x 50mm x 20mm, this receiver is small!
I’m not sure if this is still true of the version that comes with the internal speaker direct from Alex, but the speaker holes in mine were slightly imperfect. It was evident that they had been drilled by hand. Not a big deal, but I thought it worth noting –
On the right side is the tuning encoder. It rotates smoothly with no click stops, for that “big receiver” smooth tuning feel. Also on the right side is a 3.5mm jack for the IQ output –
This was the second iteration of this receiver. The first one, named the Belka-DSP, covered 3.5-31 MHz. The Belka-DX covers 1.5-31 MHz. There is now a newer version, known simply as “Belka”, that has impressively continuous coverage from 0.1 MHz – 31MHz. Yes – 100KHz to 31MHz!
There are, by now, a number of quite detailed reviews of this series of receivers online. One such review, which gives a good overview of the capabilities of this pint-sized communications receiver, was written by Dave N9EWO. Since purchasing my Belka-DX almost 3 years ago, I have used it regularly. There are several features that I find very compelling, which distinguish it from many other shortwave portables –
There is no chuffing or soft-muting in between frequency steps. As a result, when on the smallest frequency step of 10Hz, the effect is of smooth, continuous tuning.
Unlike the CC Skywave SSB and, I believe, many other portables of it’s type, it is absolutely solid on SSB and CW receive. The carrier injection on my C Crane receiver was unsteady on strong signals, leading to chirping on CW, and similar frequency instability on SSB. For a short while, I owned a CountyComm GP-5 SSB, which was even more unsteady. The Belka-DX handles like a proper communications receiver in this regard, being rock steady on strong and weak signals alike.
The frequency display is accurate. As far as I can tell, it is accurate to better than 10-20Hz across the frequency range. Because of this, I can easily tune it to a frequency, and know that it is there. The Belka-DX employs a 0.5ppm TXCO and as a result, has a high level of frequency stability. My Skywave SSB only tunes in 1 KHz steps. To interpolate between those steps, you have to push a button to engage the fine tuning, but are not able to read the frequency accurately in between those 1 KHz points. For many users, this might not be an issue, but for those who listen out for weak beacons and other signals that are not on 1 KHz “channels”, the continuous tuning and accurate frequency readout on the Belka makes such monitoring much easier. A couple of years ago, I went on a 4 /12 month long campervan trip around 6 Western states. At the time, one of my interests was listening out for low-powered unlicensed HF beacons. Standing in the vast expanses of the desert with the little Belka-DX in my hand, hearing a weak low-powered CW beacon from hundreds of miles away was magical. These beacons are home-made affairs, and usually running somewhere between 30mW and a watt. Being able to dial in the precise frequency on a handheld receiver that is even sensitive with the set-top whip is a boon with such pursuits.
You can tailor the passband for each mode. With my C Crane Skywave, and I believe many other similar receivers, the adjustable filtering (if available) is audio filtering, and doesn’t occur in the RF stages. The Belka is an SDR, and the custom adjustable filtering is the equivalent of filtering in the RF or IF stages of a conventional superhet.
Two things that I wasn’t too keen on, and which have been amended in the 0.1-31MHz version –
In CW mode, the frequency display doesn’t indicate the operating frequency. For example, with a 700Hz sidetone pitch selected, if you want to receive a CW signal on 7030 KHz, you have to tune the receiver 700 Hz below that frequency i.e. to 7029.3 KHz. You do get used to it, but it would be nice to have it display the actual operating frequency in CW mode. In the newest version, the 0.1-31MHz version, I have read that the receiver displays the actual operating frequency in CW. If you’re concerned with being able to read out the exact frequency (if searching for weak beacons on non-standard frequencies, for example) you’ll still need to ensure that you tune to the correct sidetone frequency in order for the frequency readout to be accurate. Personally, I’d love a sidetone feature for this, but I doubt that too many others would consider it to be an essential feature in a receiver (as opposed to a transceiver).
When stepping through the memory channels, you cannot hear those channels as you cycle through them. In order to hear the selected channel, you have to press the appropriate button to select and load it. Thus, you cannot easily scan through a number of preset memory channels to listen for activity. As with 1 above, I this has been remedied in the newest version of the Belka.
The audio quality from the Belka-DX is excellent when used with earbuds. The internal speaker doesn’t do it justice, though it is very useful when taking the receiver on outings. Power from the audio amplifier is adequate for most applications, though when plugging an external speaker in, it helps to use one that is sensitive. Some people use powered speakers. I have two external speakers on the bench, both unpowered, that I use with it. The main one is an MFJ-281 ClearTone speaker. It is sensitive, and produces good volume. The audio response from the mylar cone is restricted, and what I would characterize as communications quality. Audio is clear and intelligible. The speaker appears to have a natural resonance at around 650-700Hz, which is useful for CW. For those times when I need a little more fidelity, such as when listening to strong SWBC stations, or hams on AM, I use an old and compact hi-fi speaker manufactured by Cambridge Soundworks. It was discarded by one of my neighbors, and appears to be a mid-range unit. It is not as sensitive as the MFJ ClearTone speaker, but the Belka will still provide enough drive in a small, quiet room, which perfectly describes the conditions in my shack.
The small size and slim dimensions of the Belka-DX make it ideal for traveling. When using it at home with an external antenna connected, the ergonomics and ease of use are much improved when mounted on some kind of stand. There are a number of stands available, as well as files for those who wish to 3D-print their own. I remembered a clamp I once bought, that was designed to hold a cellphone for attaching it to a tripod, for making videos. The Belka is not quite as wide as a cellphone, so I used a couple of pieces of dense foam to pad it out, and screwed it to a small tabletop tripod. It works quite well, and improves the ease of use drastically when listening at home. When mounted like this, it feels like a serious and very usable SWL set-up. In the various SWL groups on FB that I frequent, I often see questions from folk asking about receivers that are good for SWL’ing. Portables such as the Tecsun PL-880, along with other similar receivers are often recommended. I think that this Belka makes an excellent receiver for all-round shortwave listening. It is not available in as many outlets as the more traditional shortwave portables, which is why I think that it isn’t as popular in the SWL community as it should be. If you are listening mainly to AM broadcasts on shortwave, then many of the portables will most likely work well. If you do a lot of SSB and CW listening though, the Belka is a solid and, to my mind, preferable option.
In the following picture, my Belka is mounted on a mini tripod (an Ultrapod) and connected to the MFJ ClearTone speaker. Behind and underneath the Belka, you can just see an Altoids tin which contains a high pass filter with a cut-off at about 2700 KHz. It was designed to prevent overload from strong local AM broadcast stations. More on that later in this post.
The Belka-DX is surprisingly sensitive when listening outdoors with the included telescopic whip. It does need a counterpoise, or the received signal strength suffers greatly. If you are holding the receiver, then your body acts as the counterpoise. If you are listening on earbuds or headphones, then the headphone cord acts as a counterpoise. If the receiver is sitting on a surface and using the internal speaker, then you’ll need to connect a counterpoise wire somehow. At home, it works really well when connected to my outdoor antena, which is a doublet at 47 feet, cut roughly for 40M, fed with 300 ohm twinlead, and matched to coax at the entrance to the shack, with a balun and Elecraft T1 tuner. I tune the T1 by squirting RF into it on the nearest amateur band. If you are using your outdoor antenna for listening only, then a simpler arrangement would suffice. This just happens to be the one antenna I also use for my ham exploits.
I live in a densely populated urban area, within a few miles of several medium power (5KW) AM broadcast stations. They often break through when I am using the external antenna with receivers that don’t have narrow filtering on the antenna input. My Belka-DX experiences strong AM breakthrough when used on the external antenna at all frequencies up to 4530 KHz. The moment I tune above 4530 – even by a single 10Hz step, the breakthrough stops instantly, suggesting that a different bandpass filter is switched in at the point. According to the manufacturer-supplied block diagram of the first version of Belka, known as the Belka-DSP, the input bandpass filters are from 3.5-7.5MHz, 7.5-15MHz, and 15-30MHz. The block diagram can be seen on this page by Fernando Duarte. I assume that for the Belka-DX, with it’s extended coverage down to 1.5 MHz, one of the bandpass filter crossover points is at 4530 KHz, the point above which all AM BC band breakthrough stops.
To solve this problem of breakthrough, I resorted to a little high pass filter that I have used successfully with other receiver projects. It’s a high pass filter that was designed by David WA7JHZ, details of which were given in K4SWL’s very wonderful and informative SWLing Post blog. You can see it here. David built his with molded chokes. I built versions with both molded chokes and toroids, and compared the response curves.
Trusty Altoids tins to the rescue. Here’s the version built with molded chokes, purchased from Tayda Electronics. The chokes are mounted vertically, and are a little hard to see in this image –
The small holes in the base of the tin were left over from a previous project that didn’t work out.
Then I built another high pass filter with toroids instead of molded chokes. I figured the toroids should have slightly higher Q and would present a better response curve. All 4 inductors were wound on T37-6 toroid cores with 26 AWG wire. The 2.7µH inductors had 30 turns and the 1µH ones 18 turns. The wires supported them about 4 or 5mm above the ground plane of the Altoid tin –
Dang, after all these years, Altoids tins still make very serviceable and cheap enclosures for small projects!
These filters were designed for input and output impedances of 50Ω. My one external HF antenna is a 40M doublet fed with 300Ω twinlead, and matched to 50Ω coax with a 1:1 balun and Elecraft T1 tuner. As mentioned previously, I briefly transmit a small amount of power on the nearest ham band to where I want to listen, to tune the T1. A manual tuner could be used here instead, and tuned for maximum noise. For listening, this is not too critical a procedure, and a single tune will cover the receiver for listening on a wide range of frequencies. The antenna input of the Belka is matched for the high impedance of the supplied short telescopic whip, and not for a 50Ω antenna. Nevertheless, I went ahead and plugged both versions of this HPF in between the antenna and the receiver, and they both served to completely eradicate every single trace of AM BC band breakthrough.
Using a NanoVNA, I measured the response curve of both filters from 1.5 MHz to 30MHz. Here’s the curve for the filter built with molded chokes –
FREQUENCY (MHz)
INSERTION LOSS (dB)
30
0
20
0.1
15
0.25
10
0.5
3.7
1
3
3
1.7 (1700 KHz)
41
1.5 (1500 KHz)
49
The 3dB cutoff point of this filter was actually 3 MHz, and the insertion loss small, with a virtually flat response from the 80M band up to the top of the 10M band. Here’s a close-up of the response between 1.5 MHz and 4 MHz –
The insertion loss of the toroid filter in the passband was a little lower, For all practical purposes though, there would be no discernible difference between the two filters. If you hate winding toroids, then by all means, build this filter with molded chokes, and it will kill your AM BC band breakthrough just as effectively as if you’d built it with toroids. Here’s the response curve of the toroid version from 1500 KHz to 30 MHz –
And from 1500 KHz to 4 MHz, giving a closer look at the area around the the 3dB cutoff point –
FREQUENCY (MHz)
INSERTION LOSS (dB)
30
0
20
0.04
15
0.12
10
0.25
3.7
0.82
2.8
3
1.7 (1700 KHz)
40
1.5 (1500 KHz)
48
There are quite a few internally generated birdies throughout the whole coverage range. However, the majority of them are only audible with no antenna connected, and are masked by band noise. The others, although audible over the band noise, are not troublesome. For a receiver this compact, and with this overall level of performance, it’s a small price to pay. I rarely noticed them during normal use. It would be nice for the end-user to have a way to update the firmware, though the extended coverage down to 100KHz that the new (V3) Belka enjoys required a hardware upgrade in the form of an extra bandpass filter.
For a more complete description of the improvements made with the newest Belka version, see 13dka’s guest post on Thomas K4SWl’s excellent SWLing Post blog. In short, the Belka is a fantastic general coverage shortwave receiver. It performs and handles like much larger tabletop communications receivers. It is so small that it can be carried anywhere with great ease, making the decision to do a little SWL’ing while on a hike, a walk, or any trip, a no-brainer. You can do a lot of serious shortwave listening with this receiver. Ordering direct from Alex in Belarus offers by far the lowest price and is, in my opinion, the way to go. When I think of my first communications receiver, an old, huge and very heavy British military R107 boat anchor, it is amazing to think that this light and svelte pocketable Belka-DX handily runs circles around it. An SWL can positively rule the shortwaves with this tiny and light miracle of wireless!
There are many other, far more comprehensive reviews on this receiver, but I have been wanting to sing the praises of the Belka (which is Russian for squirrel) for a long time now. I needed to get this out.
Not scary, frightful, just frightful activity wise.
I got soaked coming home on Friday. I was following the weather and radar all day and was expecting thunderstorms here at work when I left for the day. It was bone dry, but the skies were darkening. All the way on the drive home, I could "feel" that darkness behind me, rather then see it in the rear view mirror. As luck would have it, as dark as it was, it didn't rain and I thought I would beat the storm home. As I got out of car in front of the house (I park on the street), there was a cloudburst. It began raining at a rate of over an inch an hour, with huge, heavy drops that actually hurt when they landed on my arms. I got drenched enough that I had to change clothes once I got inside.
That set the tone for the weekend's weather. It was so humid that the lawn didn't dry out all of Saturday, so we couldn't mow. And that was actually a good thing as the temperature/humidity index made it feel like it was over 100F. We probably would have ended p with heat exhaustion. I told my son that if worse comes to worse, we'll buy a sheep. HI! We ended up getting hit with more thunderstorms and about 0.69 inches of rain later in the afternoon. I was going to grill burgers for dinner, but had to resort to indoor cooking instead.
On Sunday, I got on HF for a little bit around 1:00 PM (17:00 UTC). The bands were a mess. I did not hear anyone on any band except for 20 Meters, where I heard a solitary station, NM8GS around 14.038 MHz.
It was the light ship Huron that was on the air for Lighthouse and Lightship Weekend. They was calling CQ and I worked them easily on the first try. That was when I looked up at HamClock and saw that the K Index was at 6.3. Argh! The bands were pretty much a wasteland. Speaking of which, I just recently downloaded the SpaceWeatherLive app onto my phone.
It's a freebie and you can find it in Google Play and the iTunes store. You can set it up so that you will be alerted whenever there's a solar flare or a CME. A good tool for those of us who are denizens of the HF bands. It was not difficult to understand why the bands were so noisy and dead at my QTH as I was getting alerts for M Class flares almost continuously! One approached M7.2 on Saturday afternoon - almost X Class! I was also getting alerts that there were "minor" radio blackouts. Ha! They appeared to be a bit more than minor at my QTH!
I ended up using the time to fabricate my "new" drive on mast holder. I wanted to take pictures of it "in action" so to speak, but due to even more thunderstorms yesterday afternoon and early evening, that became an impossibility. Today is supposed to be dry all day, so maybe tonight I'll get the chance to get a few quick photos. I did something a little different this time and it's easier to explain with photos as a visual aid.
We ended up getting an additional 0.72 inches of rain yesterday, so we got over an inch and a half for the weekend. Up until recently, it's been a very dry Summer in South Plainfield. Whenever a heat wave broke with thunderstorms, it seemed they always skirted to either the north or south of us. We're making up for that now. Tomorrow evening there is a 605 chance of showers and thunderstorms, which I hope does not pan out. Tomorrow evening is National Night Out, and SPARC will be at the event, handing out literature promoting Amateur Radio to the community. I'd hate for rain to spoil the event.
Also, I've been keeping an eye on Hurricane Debby. It looks like as she winds up the East Coast, she'll be downgraded to a tropical storm, but there is potential for major flooding either Thursday or Friday. Hurricane Ida is still fresh in my mind when we got 9" of rain in one day, just a few years back. We lost Marianne's car when the parking lot where she works became a lake that night. I don't want to go through that again!
Over the past few weeks I’ve had time to examine many dozens of diodes, mostly germanium, in my crystal radio diode collection. Many of them were removed from equipment built in the '50s and '60s (old diode matrix boards), some are vintage NIB 1N34As w...
Over the past few weeks I’ve had time to examine many dozens of diodes, mostly germanium, in my crystal radio diode collection. Many of them were removed from equipment built in the '50s and '60s (old diode matrix boards), some are vintage NIB 1N34As while others are modern SMD Schottky style diodes.
There are numerous excellent websites such as this one by Dick Kleijer or SV3ORA's site ... all describing elaborate ways to determine which diode is ‘the best one’ (the holy grail diode!) for crystal radio work. Most methods use a vigorous, somewhat complex test procedure plus a lot of math, most of which is well beyond my old brain, in attempts to flesh out each diode’s inherent characteristics ... as the sites referenced above illustrate, the simple appearance of a crystal diode belies its complexity and determining diode behaviours can be more challenging than one might suspect.
My testing procedures were much more basic, and in the end, may hopefully reveal the best diode in my collection. I think one needs to undertake this with the understanding that there really is no overall ‘best' crystal radio diode but rather, only a diode that is best for your particular system and what works best in my system may not necessarily be the best one in yours.
My plan was to measure a few diode behaviors, shrink the list of candidates and then compare them against each other in my system's high-Q tank circuit.
My first step was to measure Vf or the forward voltage needed to ‘turn the diode on’. This can usually be determined to reasonable accuracy by using the diode test function on most digital multimeters. I’ve always supposed that the diode with the lowest Vf turn-on threshold would probably be the most sensitive, but is it the only factor? Hopefully my tests would indicate if anything else is in play.
The next task was to determine the minimum signal level of a 1000 Hz modulated carrier on 1400 kHz that could be detected by each candidate diode. An RF probe was used to measure the level of signal capacitively coupled into my crystal radio’s antenna tuning stage which was then lightly coupled into the detector stage, using the diode under test. No importance was given to the actual base level of this signal other than to note the level at which it could first be detected by ear (using sound powered phones) and making sure the coupling distance between stages remained the same for all diodes under test. This allowed me to compare weak-signal diode ‘sensitivity’ to the diode’s previously measured turn-on point or Vf value. Would the diode with the lowest Vf also be the most sensitive when used in a detector circuit composed of complex impedance, resistance, reactance and capacitance values that the test diode would be looking into?
The RF signal coupling was adjusted so the injected carrier could be varied between 0 and 10mV as measured on the RF probe. For each diode, the signal level was slowly increased from ‘0’ until the 1400kHz tone-modulated AM signal could first be detected.
The lowest 'first detected' signal level was .6mV while the highest level required 3.4mV, representing a pretty good range of diode behaviours. There were 49 different diodes in the test pool.
Four of the 49 diodes detected the .6mV signal, six detected the signal at .7mV, and nine first detected the signal at .8mV. The remainder required a still higher level of injected signal. The average level of first detection was 1.2 mV.
Of the four .6mV ‘best detectors’, their turn-on Vf values ranged from .15V to .38V while the .7mV and .8mV detectors had a Vf between .181V and .40V!
It seemed, not surprisingly, that generally the higher the Vf turn-on threshold, the greater was the level of signal injection needed for first detection … but evidently using the Vf value alone to determine the ‘best diode’ was not the hard axiom I had always assumed it to be!
Since a low Vf was not necessarily needed for good sensitivity, would there by any other tests that might indicate best performance?
The next trial was to measure actual diode currents in my hi-Q detector while receiving a lightly-coupled constant level input signal (1400kHz) to see how this value related to Vf. Measured diode currents (Id) varied from 9uA to 14uA for the same level of input signal, with the diode having the lowest Vf also producing the lowest current level ... hhhm! There was more to this than I expected, but generally, the lower valued Vf diodes tended to produce the most current and consequently the louder headphone signal … but not always! Some diodes with a Vf as high as .46V yielded high currents!
This now begged the question, “Does the higher current diode with a higher turn on (Vf) prove to be a better overall performer than the diode that turns-on early but produces a weaker signal?” What is the relationship between diode current and weak signal detection?
The next step was to express the relationship mathematically by calculating the ratio between the diode’s Vf and the level of diode current (Id) measured in the previous test (Id / Vf). Each diode could then be assigned a number (Vdx) that might possibly indicate it’s true performance potential in my own system.
The diodes with the highest Vdx values would then be A-B tested under real receive conditions to see if any (or just one!) particular winner(s) might emerge … and if Vf was as critical as initially believed.
The Vdx values proved most interesting and seemed to account for some of the anomalies noted in earlier measurements with some of the higher Vdx values coming from diodes not necessarily with a low Vf. I’m hoping that this sorting concept properly takes into account both turn-on level (Vf) and current level (Id), since a higher level in either number will compensate for a lower level in the other. Vdx values ranged from 23 to 66, with seven diodes in the higher 53-66 range.
Click Image For Larger View
All of the 49 diode's test parameters were put onto a spreadsheet and listed in order of their Vdx value.
Click Image For Diode Spreadsheet Data
The highest Vdx assignment of 66 went to my 40-year junkbox resident, a JHS Sylvania 1N3655A microwave mixer diode. It will be interesting to see if it really is the best of the lot! Although it did not produce the loudest signal (Id) compared with others, its Vf turn-on was an impressive .181V and its weak-signal detection level was good although not the lowest. A couple of the UHF diodes exhibited the interesting behaviour of picking up the UHF data stream 'clicks' from my nearby wifi booster. The 1N3655A was one of them.
1N3655A Vf = .181V Id = 12uA Vdx = 66
Diode #2, with a Vdx of 62, is a mystery diode with a very low Vf of .197V. It was slightly louder and oddly enough, dug down slightly further than the 1N3655A, which had a slightly lower Vf. Although I don’t recall specifically, I suspect the diode may have been removed from a VCR front end many years ago.
Mystery diode Vf =.197V Id = 12.2uA Vdx = 62
Diode #3 with a Vdx of 61 is a modern SMS7630 Schottky microwave detector diode in an SMD package. Although it did not produce a competitive level of loudness (Id) in the diode current test, its shockingly low Vf turn-on of .147V and weak-signal detection threshold were the best of all diodes tested. Before testing, all SMD diodes were mounted on small PC boards in order to attach leads.
SMS7630 Schottky Vf = .147V Id = 9uA Vdx = 61
Diode #4 (Vdx of 60) is an ISS98, another modern Schottky microwave detector. I recall seeing this diode recommended for good performance in an FM crystal radio detector. Its sensitivity level was excellent.
ISS98 Schottky Vf = .211V Id = 12.5uA Vdx = 60
Diode #5 (also with a Vdx of 60) appears to be a normal germanium of unknown type. I suspect it was used as an RF mixer since it was found on a small printed circuit board with three others, connected in a diode ring configuration typically seen in balanced RF mixers. It produced high current as well as good weak signal capability.
Mystery diode Vf = .22 Id = 13.2uA Vdx = 60
Diode #6 (Vdx of 55) also looks like a germanium of unknown type with a body striping of gray-white-green-gray. If the last band is ignored, this could be a 1N895, a UHF germanium diode. It shows the typical internal cat-whisker type of junction often seen on the 1N34 germaniums.
Mystery diode Vf = .238V Id = 13uA Vdx = 55
Diode #7 with a Vdx of 53 is marked as a ‘95481’ on a green body. It had excellent sensitivity and produced a strong signal (Id), elevating it to the top tier to be looked at more closely.
'95481' Vf = .246V Id = 13uA Vdx = 53
Diode #8, another germanium mystery, earned a Vdx of 49 due to its fairly high Id level.
Black 'T'. Vf = .258V Id = 12.5uA Vdx = 49
The rather beat-up looking Diode #9 is marked with what appear to be house numbers, '1846' and '6628'. I believe this was pulled from an old portable radio's FM section many years ago. Interestingly, like some of the UHF mixer diodes, '1846 / 6628' detects my high speed modem data stream clicks. Additionally, this tortured specimen produced the highest level of signal among all 49 diodes, with an Id of 14uA.
Vf = .294V Vdx = 48 Vdx = 14 (Schottky?)
Diode #10 appears to be the brother of Diode #8 with a Vdx of 48. Although it has a lower turn-on point and was a better weak signal detector, it did not produce as much Id as its sibling, dropping it one notch lower on the list. Like its brother, it also has the mystery 'T' marking. Both are most likely unmarked 1N34As.
Vf = .252V Id = 12 Vdx = 48
As well, three other diodes garnered my interest. Although they ranked lower than I expected, all had previously been found to be good detectors in my system. Their lower ranking may be a hint that my system of grading is not a valid method of determining best performance. All three will be given a harder look in the upcoming elimination tests.
The first is the germanium FO-215. Often touted as 'the holy grail' crystal radio diode but I have never found it to be particularly outstanding. Maybe my system has a lower Q than it really needs in order to show its stuff. This diode is shown on the bar graph above as #11. During testing, it appeared much less capable of weak signal detection than most others but its low Vf and high Id elevated its overall ranking.
Vf = .272V Id = 13uA Vdx = 48
The second diode is the Soviet-era D18, a military-grade germanium in a glass '50s-style package. I have previously found it to be a very good detector but its high turn-on level lowered its ranking. The D18 appears on the bar graph as #12.
Vf = .366V Id = 12.2uA Vdx = 33
The third diode is a vintage Sylvania 1N34 from the 50s and likely one of the first 1N34s to be manufactured. Although it produces a loud signal, its Vf was higher than expected. As I recall, it was salvaged from an old parted-out Heathkit. It appears on the bar graph as #13.
Vf = .335V Id = 13uA Vdx = 39
As mentioned earlier, one can measure and calculate a large amount of data for crystal diodes while they sit passively on the bench but they really need to be mounted, tested and compared in the actual system in which they will be used. Comparing diodes 'A-B' style in real time with weak signals may be better than any measurements made on a diode being bench-tested.
Will a new ‘holy-grail’ emerge from the pile? This type of testing requires a lot of careful listening so time will tell.
Testing will be ongoing over the summer / fall months ... stay tuned for the final results, hopefully in time for the fall DX season!
I got this short review from my friend, Mike, K8XF. Mike is a former ships radio electronics officer, a great CW operator, and has a collection of dozens of straight keys, paddles, and bugs. Recently, he purchased a CT-73MX from Yury, UR5CDX, and I asked him to do a short review. As you’ll see, he highly recommends this key.
The CT-73MX from Yury, UR5CDX.
I enjoy using well built paddles that wont move around your desk. If you do as well, consider the CT-73MX from Yury, UR5CDX. This Ukrainian paddle has a square base and is chrome plated. I chose this model because it is heavier than the brass model. The plating is excellent, and this paddle can be adjusted for sending easily.
This paddle is not as expensive ($178) as a Begali and is built very well. For an additional charge, you can have your call inscribed on a small plate placed on top of the base in front of the paddle. I did not do that.
Yury makes several other models, so be sure to visit his website. His QTH is in the center of Ukraine and so far has not been hit by Russian drones. Yury ships all orders via Poland due to the war. Via Poland, it took over three weeks to receive this paddle.
Curious about what you can hear on shortwave ham radio? This video is a brief survey of the diverse world of communications on the shortwave spectrum. Expand your radio horizons and enhance your emergency communication preparedness by tuning in to the world of shortwave ham radio. If you’ve started delving into radio communications beyond local […]
Turning back time to virtually witness a critical historic method of shortwave communication using the fundamental mode of continuous wave modulation. This is a film from 1944, teaching the basics of Morse code, for military comms. What is the proper (and most efficient) technique for creating Morse code by hand, using a manual Morse code […]
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