Category Archives: Longwave

Guest Post: Radiofreunde NRW’s DXpedition-grade signal distribution system

Many thanks to SWLing Post contributor, Joachim von Geisau (DH4JG), for the following guest post:

Signal distribution at SWL camps: The new JK-1000 HF distributor

by Joachim von Geisau (DH4JG)

The Friends of Radio NRW – an independent group of shortwave listeners and radio amateurs in Germany – have been organizing 2-3 SWL camps per year for a number of years, where they meet as far away as possible from electrical noise in order to listen to shortwave together.

To distribute antenna signals, we have previously used an RFT AVV01 antenna distributor.

At an SWL camp there are high demands on signal distribution. Both very weak and strong signals should be distributed well, un-distorted, without noise and other interference. The signal levels are approximately between 0.2 ?V (S1) to over 5 mV (S9 + 40 dB), with a frequency range of at least from 150 kHz to 30 MHz, thus broadcast bands from LW to SW are covered, also all amateur radio bands from 160 m to 10 m.

Popular among listeners are RFT AVV01 RF distributors from the former GDR, at least 30 years old. However, the use of an AVV01 has several disadvantages: high power consumption, difficulties in getting spare parts, high upkeep with corroded contacts and the like. In addition, the transmission of the LW/MW range drops, which is a disadvantage especially for MW listeners. The NV-14 system from Rohde & Schwarz from the late 1960s has the same weaknesses.

Two years ago, the desire arose to develop a concept for the replacement of the RFT system.
The following aspects were important:

Frequency range at least 100 kHz – 30 MHz, as linear as possible
frequencies below or above desirable
Running on 12 V DC or integrated noise-free power supply
Remote power supply for active antennas
Robust structure
Versatility
Hobby friendly budget

The amateur radio market offers several products for RF signal distribution (e.g., ELAD, Bonito et al.), but no solution to distribute 6-8 antennas to 10-12 receivers. It was clear from the beginning that DIY development was inevitable.

The starting point of the considerations was to integrate remote power supply for active antennas, an amplifier stage and a distribution network.

Such a distributor is able to distribute an antenna signal to several receivers; several antennas require several such distributors, which led to the decision to implement the project in plug-in technology.

With OM Frank Wornast DD3ZE (www.dd3ze.de), known e.g. for his converters, filters and the like, a well-known RF developer could be won, who took over the implementation of the concept based on the detailed specifications. OM Wornast first produced a prototype without remote power supply, which already did an excellent job of RF signal distribution.

A “hardness test” at an SWL camp showed that this distribution module easily fulfilled our requirements: Frequency range 10 kHz – 50 MHz (also usable with a few dB loss above 50 MHz). Supplemented by a switchable remote power supply and a 90V gas discharger at the antenna socket, the final PCB layout was created, representing the core of the new HF distribution system of Radio Freunde NRW

The distribution block consists of the following components:

Input with 90V arrester & 100 kOhm MOX resistor to dissipate static interference
Remote power supply, switchable, 10-14 V, max. 350 mA
Amplifier stage with 14-14.5 dB
Resistor network for distribution

The device is characterized by a very smooth frequency response and has a very low inherent noise. It offers the possibility of using levels of -120dBm with very good SNR
to process up to strong levels of up to + 14dBm. In addition, the reception on VLF is now possible, which did not work with the previous system.

The PCB is designed in a very practical way: series resistors for LEDs are integrated as well as fixing points for coaxial cables. The remote power supply can be switched separately, but can also be used permanently by means of a jumper.

With this concept, the distribution block can be used universally: use on an active or passive antenna with distribution to several receivers, by means of a step switch in front of it also for several antennas; if you leave the remote feed path unconnected, the block can also be used as a simple distributor, so it is almost universal for hobby purposes.

For use on SWL camps, we decided to install them in 19 “rack-mount technology. A standard rack can thus accommodate 4 distributors and a power supply, allowing distribution of 4 antennas to 12 outputs each. An example of the installation is shown in the following picture: Parallel to the input is another BNC socket, which is connected via a C 100 nF where the input signal can be used DC-free for measurement purposes or the like. The distribution unit is installed in a transport case. The components themselves are mounted in slide-in housings which are provided with a corresponding front panel: Such front panels might be obtained from CNC manufacturers.

On the back + 12V DC must be supplied as operating voltage. For the power supply units, we opted for linear power supplies because we have made the best experience with these without interference. For a distribution unit with 4 slots, a power supply with 12V 1A is sufficient – each distribution block takes about 55 mA, an active antenna up to 150 mA, so even with “full load” a power supply with 1 A is sufficient. The distributor was tested with various well-known active and passive antennas, including a PA0RDT MiniWhip, active loops, long wires and T2FD.

Due to the wide input voltage range, the module can handle nearly any antenna. The cost for a distributor for 4 antennas amounts (depending on the version: housing, sockets, switches, power supply, etc.) to about 700-1000 €. That may seem a lot at first glance. However, taking into account that a simple 5-gang distributor from mass production costs already around 250 ¬, the cost of the distribution of 4 antennas to each up to 12 outputs are not that much. The Friends of Radio NRW use two of these distribution units for SWL camps.

If you are interested in building one, please contact the author ([email protected]) for further information. The development history of the distribution unit is also available at www.dx-unlimited.eu.

Wow! What a beautifully engineered antenna distribution solution, Joachim! I love how you worked together to sort out all of the requirements for your system then build it for ultimate performance and flexibility. No doubt, you and your colleagues at Radiofreunde NRW posses a lot of design and engineering skills! Simply amazing and thank you for sharing your design with the radio community!

Contact Joachim for more details and check out notes and discussion at www.dx-unlimited.eu (may require registration).

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Shortwave Radio Audio Archive: A treasure trove of radio history and nostalgia

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One of the most amazing things about hosting and curating a massive collection of shortwave radio recordings is listening to each recording as they’re published on the site.

I created the Shortwave Radio Audio Archive (SRAA) in 2012 as a dedicated space to post and share off-air recordings with the world. Listening to SRAA recordings and subscribing to the podcast is 100% free, and entirely void of any advertising. The fact is, I pay for this site out of my own pocket, although some of your generous coffee fund and Patreon gifts are used to reinforce the archive’s longevity and future.

Not only does the SRAA serve as a historical record of radio–and even as audio samples for musicians–it’s also for radio listeners like us to enjoy. We have over 3000 podcast and RSS subscribers. We invite you to subscribe as well as to contribute content in the form of your own radio recordings!

Great content, great contributors

Speaking of recordings, check out a sampling of our latest offerings from our amazing contributors:

Note that you can subscribe to the Shortwave Radio Audio Archive as a podcast via iTunes or by using the following RSS feed: http://shortwavearchive.com/archive?format=rss You can also listen via TuneIn.

Of course, one of the best ways to listen to recordings and read all of the recording notes is by visiting the SRAA website.

Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

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Krasne Antenna Array: Help Rick solve a 22 year old mysetery

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The mystery array

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!

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WRTH 2020: A look inside

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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.

Purchase your copy of WRTH 2020 directly from WRTH’s publishers, or from a distributor like Universal Radio (US) , Amazon.com (US), or the Book Depository (international).

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Europe 1 to close 183 kHz longwave service December 31, 2019

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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)

CEO ELLE International

Thanks again for sharing this news, Gaétan.

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WI2XLQ: Brian Justin’s annual longwave broadcast

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Canadian Reginald Aubrey Fessenden in his lab believed circa 1906 (Source: Radio Canada International)

(Source: ARRL News via Harald Kuhl)

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.

Click here to read the full article on the ARRL News.

Listener reports may be sent to Brian Justin, WA1ZMS, at his QRZ.com address.

If you would like more information about Brian Justin and WI2XLQ, check out our interview with him in 2013. Indeed, I successfully heard the 2013 WG2XFG broadcast and posted this audio clip on the Shortwave Radio Audio Archive.

Additionally, SWLing Post reader, George Stein has a very personal connection with radio pioneer, Reginald Fessenden: click here to read his story.

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Reminder: Grimeton Radio / SAQ Christmas Eve Broadcast

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.

QSL-reports to SAQ are kindly received via:

– Reception report form at alexander.n.se/receptionreport
– or via: SM bureau
– or direct by postal mail to:

The Alexander Association
Radiostationen Grimeton 72
432 98 GRIMETON
S W E D E N

The SK6SAQ amateur radio station will be QRV on the following frequencies:
– 7.035 kHz CW or
– 14.035 kHz CW or
– 3.755 kHz SSB

Two stations will be on the air most of the time.

WELCOME!
World Heritage Grimeton Radio station and The Alexander Association

For further details visit grimeton.org or alexander.n.se

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