Shortwave listening and everything radio including reviews, broadcasting, ham radio, field operation, DXing, maker kits, travel, emergency gear, events, and more
Many thanks to SWLing Post contributor, Rick Slobodian, who seeks help solving a 22 year old mystery. Rick writes:
[Perhaps you can help me] explain this antenna….a 22 year old mystery antenna (see photo above)? What sort of antenna is this and how does it work? It’s at 49.8994 N 24.685 E near Krasne, Ukraine.
I was at this transmitter site in 1998.
Antenna switch room
I was writing articles for a number of magazines hoping to find customers for airtime and to make this site viable.
I spent all day at the site wrote extensively about EVERYTHING ELSE: the shortwave transmitters, the longwave transmitters, the shortwave antennas, the vertical long wave antennas, and the vertical MW antennas.
Longwave antenna at Krasne
HRS curtain array at Krasne
The transmitters were behemoths: Komintern Burans 500Kw 1000 Kw 1200 Kw
New 1200 Kw transmitter under construction
This antenna was over a km form the main building and they would let me go there:
I took this photo of the array as I traveled past it by train.
Its 36 towers strung in a NE SE line–over 2 km long and each tower is approximately 40 m tall.
[My hosts] were they so evasive about this antenna array yet not the rest of the site.
[There are some peculiarities:]
Do you see a feed line running along the bottom of the towers near the ground?
I do not see any tuning shacks.
Is it fed from one end or the other end or is each tower fed?
If each tower is fed, then where are the tuning shacks/phasors?
iIf it is a beverage then why so may towers and such close spacing?
Is it something completely different?
What do you think it is? How do you think it works and what would be its purpose?
Thanks for sharing, Rick! My hope is that one of the members of the Post community may be able to shed a little light on this interesting antenna array. Please comment!
I received my review copy of the 2020 World Radio and TV Handbook (WRTH) shortly after returning from holiday travels last week. I always look forward to receiving this excellent staple radio reference guide–and this is their 74th edition! The WRTH has never disappointed, so my expectations are always quite high.
Once again, the WRTH lived up to my expectations.
WRTH’s team of noted DXers from around the world curate frequencies and broadcaster information by region; while I’m not sure how they orchestrate all of this, the end result is truly a symphony of radio information. In addition to broadcaster listings, WRTH’s radio reviews, feature articles, and annual HF report make for excellent reading.
But the WRTH isn’t just a frequency guide: the publication always devotes the first sixty or so pages to articles relating to various aspects of the radio hobby. Following, I offer a quick overview of these.
The first article always features a WRTH contributor: this year, they feature Luis Cavalho who is their contributor for Portugal, the Azores and Madeira. His path to becoming a WRTH contributor began in his childhood snagging mediumwave DX with an array of portable radios. His love of radio lead him to the world of shortwave radio, WRTH and eventually his own radio website to serve Portuguese listeners.
WRTH Reviews
The second set of articles is always my favorite: WRTH receiver reviews.
This year, WRTH begins with an in-depth review of the excellent ELAD FDM-DUOr tabletop SDR receiver. Next they build on their 2019 review of the SDRplay RSPduo by exploring its unique diversity reception capabilities. They also review the AirSpy HF+ Discovery and were so impressed they awarded it the 2020 Best Value SDR.
This year, WRTH also reviewed two portable radios by Pure: the Pure Elan E3 DAB, DAB+, FM receiver and the Pure Elan IR5 WifI radio.
The final two reviews are of affordable products that offer incredible value for the radio listener: the venerable Tecsun PL-310ET ultralight radio and the Tecsun AN-200 MW Loop Antenna. I enjoyed reading a fresh review of each of these products as I’ve personally used both for nearly a decade.
WRTH Features
The first feature article, written by none other than Dave Porter, focuses on the development of HF broadcast antennas. His article serves as an excellent primer on the topic, covering Rhombic Antennas, Corner Quadrant Antennas, Log-Periodic Arrays and ALLISS /Rigid Curtain Arrays. A must-read for those who want to know more about the “business side” of a broadcast signal!
Hans Johnson’s feature, Sea Breeze and Wind from Japan, explores the story behind the broadcasts to Japanese citizens abducted by North Korea. Truly, an inspiring story of a determined and mission-dedicated broadcasters.
The following feature article was written by WRTH contributor and chief editor of the New Zealand DX Times, Stu Forsyth, who outlines the history of broadcasting from New Caledonia in the Pacific.
The next feature article focuses on the “finer points” of mediumwave propagation. I thought this was an informative and and timely article as so many shortwave DXers (including yours truly) spend time on the mediumwave bands especially during winter and times of rough HF propagation. A must-read!
Ashraf Chaaban, president of the Association des Radio Amateurs Tunisiens, takes WRTH readers with him on a visit to the Sidi Manson Transmitter Site in Tunisia in the final feature article. Having an affinity for broadcast sites, I sincerely enjoyed the focus on Sidi Manson which fell silent on shortwave in 2014.
Next, WRTH spotlight the annual Digital Update which summarizes the dynamic state of digital broadcasting. I’ve found this feature to be incredibly informative as we see how digital broadcasting is penetrating both domestic and international services.
The final article–a tradition–is the WRTH HF propagation report/forecast by Ulf-Peter Hoppe. Always an informative read especially as we work our way out of a log-term solar slump.
The 74th is another fantastic edition of the World Radio TV Handbook. As I say every year,I’ve never been disappointed with WRTH. Their publishing standards are such that the quality of their reviews, their writing, and (most importantly) their broadcast listings are simply unparalleled.
At the heart of any WRTH is an uncompromising and unparalleled amount of information regarding regional and international broadcasting.
For DXers who collect QSL cards, you’ll find that broadcaster contact information in WRTH is often more up-to-date than a broadcaster’s own website. When readers contact me asking for QSL information from an obscure broadcaster, the first place I search is the current WRTH. Remember: their information is based on volunteer contributors who specialize in specific regions of the world–the most knowledgeable regional DXers keep this publication accurate.
Transmitter building of Europe 1 with one of the radio masts in the background (Source: Wikimedia Commons)
Many thanks to SWLing Post contributor, Gaétan Teyssonneau, who notes that Europe 1 has announced that they will close their 183 kHz longwave service on December 31, 2019 at midnight. Gaétan shared the following message, in French, from Europe 1:
Cher Monsieur.
Les habitudes d’écoute étant en train d’évoluer et l’utilisation des supports numérique se multipliant, Europe 1 n’émettra plus en grandes ondes à partir du 31 décembre 2019 minuit.
Un choix assumé par la station qui a toujours fait preuve d’innovation dans sa manière de penser et concevoir l’écoute de ses programmes. l’approche environnementale a également motivé cette décision. Quitter les grandes ondes c’est aussi protéger l’environnement.
Bonnes fêtes à vous .
Constance BENQUÉ
Directrice Générale Lagardère News (Europe 1/ Paris Match / JDD)
The Canadian inventor, experimenter, and entrepreneur Reginald Fessenden has been credited as the inventor of radiotelephony. Fessenden claimed to have made his first voice — and music — broadcast on Christmas Eve in 1906 from Brant Rock, Massachusetts, although his account is disputed. As he has done each December for the past few years, Brian Justin, WA1ZMS, of Forest, Virginia, will transmit a program on 486 kHz, under authority of his FCC Part 5 Experimental License WI2XLQ ito commemorate Fessenden’s accomplishments.
Justin will transmit for at least 24 hours starting at around 2000 UTC on December 24, with a repeat transmission on New Year’s Eve likely, “keeping in step with what Fessenden was reported to have done on both nights in 1906,” Justin explained.Fessenden’s transmitter was most likely a high-speed “dynamo” or alternator — a predecessor to the later Alexanderson alternator — modulated by placing a carbon microphone in series with the antenna feed line to create an amplitude modulated signal. Fessenden a few years earlier had limited success making voice transmissions using a rotary spark gap transmitter. Fessenden fed his signal into a substantial antenna system erected in Brant Rock for his experiments. Accounts say on Christmas Eve 1906, he transmitted recordings of two pieces of music and read a verse from the bible.
Justin will use somewhat more modern equipment — a home-brew master oscillator, power amplifier (MOPA) transmitter based on a classic design from the early 1920s. It uses a UV-201 oscillator tube driving a VT-25 tube — a modern equivalent to a UV-202 — to generate “a few watts” on 486 kHz. His modulator consists of another VT-25, which uses a large inductor in the RF amplifier’s plate supply to serve as a Heising modulator. The audio program comes from a laptop computer.
“Heising modulation was used in World War I as an easy way to achieve AM in rigs such as those used in aircraft,” Justin said. “My particular Heising modulator can deliver only around 60% modulation, so an audio processor is used to help boost the average volume level ahead of the modulator tube.”
Justin uses far more modern technology to boost “the few watts” of modulated RF to drive a modified Hafler 9505 solid-state 500-W audio amplifier. “The idea for the amp came from W1TAG and W1VD,” he said, “and information on using such an amp on the 630 and 2200-meter ham bands can be found on the web.” After a multi-pole low-pass filter, the carrier output is 150 W.
Justin’s antenna is a Marconi T, crafted from a 160-meter dipole some 60 feet above ground and fed with open-wire line, which is shorted at the transmitter end. A homebrew variometer — constructed from 14-gauge wire wound on a piece of 4-inch diameter PVC pipe — is placed in series to resonate the antenna, which is fed against an extensive ground system. “Most of the RF is lost due to the ohmic losses of the ground system, but at least 15 W ERP is possible, depending on the dampness of the soil. Damp soil helps lower the ground losses,” Justin said.
SAQ Current QSL card received by Harald via the QSL bureau
Many thanks to SWLing Post contributor, Harald Kuhl (DL1AX), who shares the following announcement from Grimeton Radio SAQ:
Scheduled transmission from Grimeton Radio / SAQ on Christmas Eve, December 24, 2019
On the morning of Christmas Eve, December 24, we will try to start the old Alexanderson 200 kW transmitter, from 1924 and send out a Christmas message on VLF 17.2 kHz CW. The transmitter will be tuned up from around 08:30 (07:30 UTC) and a message* will be transmitted at 09:00 (08:00 UTC).
Guests are welcome to attend the transmission at the radio station in Grimeton from 08:00 local time. The Alexander association will arrange coffee and Christmas cookies, free of charge. No entrance fee.
For those of you who can not attend, we will broadcast the event live from Grimeton, Sweden on our YouTube Channel.
NEW !
ONLINE RECEPTION REPORT FORM – PLEASE NO E-MAIL REPORTS!
We are introducing a new online SAQ reception report form to be used by listeners to report reception of any SAQ transmissions. We are kindly asking listeners not to send SAQ reception reports via E-mail.
SAQ Current QSL card received by Harald via the QSL bureau
Many thanks to SWLing Post contributor, Harald Kuhl (DL1AX), who shares the following announcement from Grimeton Radio SAQ:
Scheduled transmission from Grimeton Radio / SAQ on Christmas Eve, December 24, 2019
On the morning of Christmas Eve, December 24, we will try to start the old Alexanderson 200 kW transmitter, from 1924 and send out a Christmas message on VLF 17.2 kHz CW. The transmitter will be tuned up from around 08:30 (07:30 UTC) and a message* will be transmitted at 09:00 (08:00 UTC).
Guests are welcome to attend the transmission at the radio station in Grimeton from 08:00 local time. The Alexander association will arrange coffee and Christmas cookies, free of charge. No entrance fee.
For those of you who can not attend, we will broadcast the event live from Grimeton, Sweden on our YouTube Channel.
NEW !
ONLINE RECEPTION REPORT FORM – PLEASE NO E-MAIL REPORTS!
We are introducing a new online SAQ reception report form to be used by listeners to report reception of any SAQ transmissions. We are kindly asking listeners not to send SAQ reception reports via E-mail.
For over two weeks now, I’ve had an early production model of the RSPdx here in the shack operating on a beta version of the SDRuno application.
In the spirit of full disclosure, SDRplay is a long-time supporter of the SWLing Post and I have alpha- and beta-tested a number of their products in the past. This early production RSPdx was sent to me at no cost for a frank evaluation, and that’s exactly what I’ll offer here. To be clear, while I am using beta software, this is not a beta SDR, but one from a first limited production run.
And thus far, I must say, I’m impressed with the RSPdx.
Upgrades
The RSPdx has been introduced as a replacement for the RSP2 and the RSP2pro receivers. It has been updated and upgraded, with a completely new front-end design.
Here are the highlighted improvements and changes:
Performance below 30 MHz has been enhanced when compared to the RSP2/RSP2pro.
Performance below 2 MHz has been substantially upgraded. Through the use of the new HDR mode, both dynamic range and selectivity have been considerably improved.
There is now a BNC antenna connector on antenna C position instead of a HiZ port. Both A and B antenna ports are SMA like other RSP models.
Let’s face it: those of us interested in low-cost SDRs are spoiled for choice these days. The market is chock-full of sub-$200 SDRs, especially if you include all of the various RTL-SDR-based SDRs and knock-off brands/models one can find on eBay.
Personally, I invest in companies that support radio enthusiasts for the long haul…those that do their own designs, innovations, and production. SDRplay is one of those companies.
SDRplay’s market niche has been providing customers with affordable, high-performance wideband receivers that cover an impressive 1 kHz to 2 GHz.
Wideband coverage can come at a cost. Unless you pay big money for a commercial-grade wideband receiver, you’re going to find there’s a performance compromise somewhere across the spectrum. On the RSP2 series, those compromises would have been most apparent on frequencies below 30 MHz.
That’s not to say HF, MW, and LW performance was poor on the RSP2 series–indeed, it was quite impressive and well-balanced; it just didn’t stack up to the likes of the similarly-priced AirSpy HF+ and HF+ Discovery, in my humble opinion. Both little Airspy SDRs have wooed DXers with their impressive dynamic range and overall ability to work weak signals in the HF portion of the spectrum.
Neither of the AirSpy HF+ models are wideband receivers, but still offer a generous range: 9 kHz to 31 MHz and from 60 to 260 MHz––about 11.5% of the frequency coverage of RSP models. (Note that the Airspy R2 and Mini do cover 24 – 1700 MHz.) For shortwave radio listeners that also want to venture into the UHF and SHF regions, a wideband SDR is still required.
It’s obvious SDRplay’s goal is to make the wideband RSPdx into a choice receiver for HF and, especially, for MW/LW DXers. But have they succeeded? Let’s dive in…
Performance
As I say in most of my SDR reviews: doing comparisons with receivers that have so many features and adjustments is never easy. In other words, we want an apples-to-apples comparison, but it can be difficult to achieve, especially with new products.
The RSPdx, Excalibur, and HF+ Discovery all used the same antenna in my tests––a large, horizontal delta loop antenna, via my ELAD ASA15 amplified antenna splitter. I’ve used this antenna splitter for years and can vouch for its equitable, lab-grade distribution of signal.
The RSPdx is not in full production at time of posting, thus application options are limited. Typically, I’d load comparison SDRs in SDR Console or HDSDR and test them with identical settings as well. At present, the RSPdx is only compatible with a beta version of SDRplay’s own application, SDRuno (which will come out of beta rior to the first major production run). The benefit of using SDRuno is that you unlock the full potential of the RSPdx, plus signal and noise numbers are incredibly accurate.
For each SDR in this comparison, I used their native/OEM application to give them the best possible performance.
I also matched filter settings and made an effort to match AGC and volume settings as closely as I could.
Additionally, I resisted the temptation of comparing my RSP2 with the new RSPdx because I didn’t want to run two simultaneous instances of SDRuno on the same computer––especially considering one was in beta.
Is this comparison perfect? Probably not, but I did the best with the time I had available. I do intend to make further comparisons in the future.
Longwave performance
Via the RSPdx’s new “HDR” mode, both dynamic range and selectivity have been considerably improved with frequencies below 2 MHz. While I’ll fully admit that I’m not much of a longwave DXer, my very first listening session with the RSPdx started in this region of the spectrum.
In fact, the first evening I put the RSPdx on the air and confirmed that I was, indeed, in HDR mode, I noticed a small carrier via the spectrum display on 171 kHz. I clicked on it and quickly discovered it was Medi 1. The signal was faint, but I could clearly ID at least one song. This truly impressed me because I believe this was the first time I had logged Medi 1 on longwave from the shack.
I didn’t connect the Excalibur at that point to see if it could also receive the faint Medi 1 signal, but I imagine it could have. I’m pretty sure this would have been outside the reach of the RSP2, however.
I tried to explore more of the longwave band, but due to local RFI (I suspect an appliance in my home), most of the LW band was inundated with noise. With that said, I did grab three of my benchmark non-directional beacons.
Obviously, the RSPdx is a capable LW receiver. I would like to spend more time on this band once I’ve tracked down the source of my local RFI.
Mediumwave/AM performance
In the past two weeks, I’ve spent many hours with the RSPdx on mediumwave.
We’re heading into the winter months in the northern hemisphere, and that’s normally when my listening habits head south on the bands.
In short: I find the RSPdx to be quite sensitive and selective on the mediumwave bands while the HDR mode is engaged. A major improvement over its predecessor.
I primarily compared the RSPdx with my WinRadio Excalibur on mediumwave since I consider the Excalibur to be a benchmark MW receiver. And, as you’ll hear in the screencasts below, the RSPdx truly gives the Excalibur a run for its money:
Note that my horizontal delta loop antenna is omni-directional, hence the tug-of-war you hear between stations in the clips above.
In truth, I could have done more to stabilize the signal on both of these fine SDRs, but I wanted to keep the comparison as fair as possible.
You might have noticed that both were running AM sync mode. It seems the sync lock on the RSPdx may have also improved––though I would need to do a direct comparison with the RSP2 to know for sure––but in terms of stability, I still found that the WinRadio Excalibur was superior. Mind you, the Excalibur is a $900 – $1,000 receiver and has the strongest synchronous detector of any radio I’ve ever owned.
Shortwave/HF
SDRplay notes on the preliminary specifications sheet that the RSPdx has been “enhanced” when compared with the RSP2 series.
And, after having spent two weeks with the RSPdx on the shortwave bands, I would say this is a bit of an understatement. For although I haven’t compared the RSPdx directly with the RSP2 yet, I do feel HF performance is substantially better than its predecessor. Indeed, in my comparisons, I often found it gave the Excalibur some serious competition. Overall, the Excalibur had an edge on the RSPdx, but the gap has closed substantially. That’s saying something.
For the comparison videos below, I also included the excellent AirSpy HF+ Discovery.
As you can see and hear, the RSPdx is now in the league of some of the finest HF receivers in my arsenal.
But I’m curious to know what you think after listening to these comparisons. Please comment!
Notch Filters
For those of you living in areas with DAB/DAB+ broadcasters nearby, you’ll be happy to note that the RSPdx has a DAB filter to help mitigate any potential overloading.
Also, if you live near a blowtorch mediumwave station, you’ll be quite pleased with the MW notch filter. It’s so effective at filtering out the mediumwave band, my local blowtorch on 1010 kHz is barely visible on the spectrum once the notch filter is engaged. (Note: I should add that neither the DAB nor the mediumwave notch filter was engaged during any of my previous comparisons above.) Check out the screen shots below showing the mediumwave band before and after the MW notch filter is engaged:
Before:
After:
Summary
For those of you looking for a budget wideband SDR with solid performance below 30MHz, look no further.
For $199 US, you’re getting a quality UK-designed and manufactured SDR in a proper metal housing. The OEM application, SDRuno, is one of my favorite SDR applications and can fully take advantage of the RSPdx’s new HDR mode. No doubt, with a little more time, most third-party SDR applications will also support the RSPdx.
Frankly, I was expecting classy mediumwave and longwave performance as this was the most touted upgrade of the RSPdx. SDRplay certainly delivered.
In my experience, SDRplay doesn’t oversell their products. Their preliminary product sheet mentioned improved performance on HF, but their press release didn’t even mention the HF upgrades. And this is where I, in particular, noticed significant improvement. Perhaps this is because I am primarily an SWLer, thus spend a larger portion of my time in the HF region.
SDRplay products also have a mature, robust SDR application via SDRuno. Day to day, I tend to use Simon Brown’s SDR Console as my primary SDR application, since it’s compatible with so many of my SDRs and also offers some of the best recording functionality for those of us who do audio and spectrum archiving. Each time I beta test or review an SDRplay SDR, however, I’m more and more impressed with SDRuno. It’s evolved from being a rather cluttered application to one with a thoughtful, cohesive user interface that’s a joy to use––a product of true iterative agility.
Indeed, after having used SDRuno exclusively these past two weeks, I believe I would consider it as my primary SDR application…if only it had audio recording in addition to spectrum recording, and could run multiple instances with multiple SDRs. Again, given a little time, I wouldn’t be surprised if some of this functionality is eventually integrated.
Questions?
Since many SWLing Post readers already own an SDR, I’m sure some of you will have questions. Let’s address a few of those right now.
Question: “I have an RSP2/RSP2pro. Should I upgrade to the RSPdx?”
My recommendation: If you are a shortwave, mediumwave, or longwave DXer, I would indeed recommend upgrading to the RSPdx. If you primarily use your RSP2 series SDR on frequencies above 30 MHz and only occasionally venture below for casual listening, then I’d keep the RSP2.
Question: “I have an RSP1a. Should I upgrade to the RSPdx?”
My recommendation: If you’ve been enjoying your RSP1a and would like to take your listening/monitoring to the next level, then, yes, I would upgrade. Not only can you take advantage of the RSPdx’s enhanced performance, but the RSPdx affords you three antenna ports, and has a more robust front end.
Question: “I have an RSPduo. Should I buy the RSPdx?”
My recommendation: I’m a big fan of the RSPduo. Unless you’re a dedicated mediumwave/longwave DXer, or you’d just like to add another separate SDR to your radio arsenal, I wouldn’t rush out to buy the RSPdx.
And while I’m offering advice, I’d like to offer my standard two cents on the subject of performance optimization: a radio is only as good as its antenna!If you have a compromised antenna, invest in your antenna before upgrading your radio. You’ll be glad you did.
Conclusion
Happily, I can recommend the SDRplay RSPdx without hesitation. This latest iteration of the RSP series SDR is a proper step forward in terms of performance and functionality––obviously implementing years of customer feedback.
SDRplay also has a proven track record of innovation and customer support. Their documentation, video tutorials, and community are among the best in the industry. Purchase with confidence.
