Category Archives: Software Defined Radio

Guest Post: Mediumwave DXing in Botswana

Many thanks to SWLing Post contributor, Peter Wilson, who shares the following guest post and recordings from his listening post in Botswana:


Peter’s receiver is a Airspy HF+ Discovery SDR using SDR Console V3

MWDX from Australia and the USA received in Botswana

by Peter Wilson

Hello Thomas.

I moved my 16.2 metre random wire slightly farther away from the house, and installed a binocular balun and connected 20m of RG58 at the far end, not the “house end”.

Peter’s random wire antenna with binocular balun

Reception examples:

1500 USA WFED Washington DC 12790km

1152 AUS 6PB
ABC NewsRadio Busselton 8469km with ABC News ID

1600 B Radio Nove de Julho ID 7234km
Sao Paulo. Brazil. ID,
Web Address and jingle. Rinsed and repeated.
Portuguese: Radio Nove de Julho [English: Radio 9th July]

1026 kHz MOZ Emissor Provincial de Manica Chimoio 1057km.
A bit parochial but features the radio Mozambique song.

850 USA WTAR Norfolk, Virginia Fox Sports Radio ID 12700km

1296 6RN ABC Radio National. Wagin, Australia 10kW 8644km

558 AUS 6WA ABC Great Southern WA Wagin 8644km


Impressive reception from your home in Botswana! Thank you so much for sharing these recordings, Peter. You’ve certainly made the most of your random wire antenna!

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Radio Waves: Old Gen FM Radio, Radio Burst Model Challenged, Iceland WebSDR, and Ida Destroys WZRH/KVDU Tower

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Dennis Dura, Troy Riedel, Dan Van Hoy, and the Southgate ARC for the following tips:


FM Radio, the choice of an old generation (Hackaday)

Had the pandemic not upended many of this summer’s fun and games, many of my friends would have made a trip to the MCH hacker camp in the Netherlands earlier this month. I had an idea for a game for the event, a friend and I were going to secrete a set of those low-power FM transmitters as numbers stations around the camp for players to find and solve the numerical puzzles they would transmit. I even bought a few cheap FM transmitter modules from China for evaluation, and had some fun sending a chiptune Rick Astley across a housing estate in Northamptonshire.

To me as someone who grew up with FM radio and whose teen years played out to the sounds of BBC Radio 1 FM it made absolute sense to do a puzzle in this way, but it was my personal reminder of advancing years to find that some of my friends differed on the matter. Sure, they thought it was a great idea, but they gently reminded me that the kids don’t listen to any sort of conventional broadcast radio these days, instead they stream their music, so very few of them would have the means for listening to my numbers stations. Even for me it’s something I only use for BBC Radio 4 in the car, and to traverse the remainder of the FM dial is to hear a selection of easy listening, oldies, and classical music. It’s becoming an older person’s medium, and it’s inevitable that like AM before it, it will eventually wane.

There are two angles to this that might detain the casual hacker; first what it will mean from a broadcasting and radio spectrum perspective, and then how it is already influencing some of our projects. [Continue reading…]

New observations challenge popular radio burst model (Sky and Telescope)

Strange behavior caught by two radio observatories may send theorists back to the drawing board.

Fourteen years ago, the first fast radio burst (FRB) was discovered. By now, many hundreds of these energetic, millisecond-duration bursts from deep space have been detected (most of them by the CHIME radio observatory in British Columbia, Canada), but astronomers still struggle to explain their enigmatic properties. A new publication in this week’s Nature “adds a new piece to the puzzle,” says Victoria Kaspi (McGill University, Canada). “In this field of research, surprising twists are almost as common as new results.”

Most astronomers agree that FRBs are probably explosions on the surfaces of highly magnetized neutron stars (so-called magnetars). But it’s unclear why most FRBs appear to be one-off events, while others flare repeatedly. In some cases, these repeating bursts show signs of periodicity, and scientists had come up with an attractive model to explain this behavior, involving stellar winds in binary systems.

However, new observations by European radio telescopes may rule out this model.

Astronomers knew that FRB 20180916B, located in a galaxy some 475 million light-years away, produces multiple bursts about every 16 days, during a ‘window’ that lasts for a few days. “The idea was that the magnetar is part of a binary system with a 16.29-day period,” says Inés Pastor-Marazuela (University of Amsterdam), the first author of the new paper. If the companion star had a thick stellar wind that absorbs radio waves, the bursts would only be visible when the magnetar was on ‘our’ side of the orbit, she explains. [Continue reading…]

New WebSDR in Iceland (Southgate ARC)

Iceland’s IRA reports on August 24 Karl Georg Karlsson TF3CZ connected a new receiver over the internet covering 24-1800 MHz

A translation of the IRA post reads:

QTH is Perlan in Öskjuhlíð in Reykjavík. These are Airspy R2 SDR receivers for 24-1800 MHz (on VHF and UHF). The antenna is a Diamond D-190.

Karl Georg stated the following on FB:
The extension is not just for 2m, it can only be on one band at a time. So if one user switches, others who are connected also move between bands. (However, you can listen to each frequency within the same band). The receiver automatically tunes to APRS QRG 144.800 MHz, see the APRS website: http://SDR.ekkert.org/map

URL of the receiver
http://perlan.utvarp.com/#freq=24890000,mod=usb,sql=-150

Thanks to Karl Georg for his valuable contribution. This is an important addition for radio amateurs who experiment in these frequency ranges, as well as listeners and anyone interested in the spread of radio waves.

IRA Board

Source Iceland’s national amateur radio society, the IRA
https://tinyurl.com/IcelandIRA

WZRH/KVDU Tower Destroyed By Hurricane Ida (Radio Insight)

The nearly 2000 foot tower utilized by Cumulus Media Alternative “Alt 92.3” WZRH LaPlace and iHeartMedia Variety Hits “104.1 The Spot” KVDU Houma LA was toppled by the winds of Hurricane Ida.

The 1999 foot structure was constructed in 1988 to host both signals. Only the bottom 150 to 200 feet remain standing. Both stations are licensed to operate with 100kW/591m, but have low powered auxiliary sites in downtown New Orleans. WZRH is located on the roof of Place St. Charles with 630w/200m. KVDU is on the Hancock Whitney Center with 1.2kW/220m.

In addition to KVDU, iHeartMedia Gospel 940 WYLD is silent at its cluster. The company reports that the remainder of its signals are now operational after all but 93.3 KQUE and 98.5 WYLD-FM were off the air on Monday.

Cumulus Media states that its entire cluster of WZRH, Adult R&B 102.9 KMEZ Belle Chasse, Country “106.1 Nash-FM” WRKN Picayune MS, and Hot AC “106.7 The Krewe” KKND Port Sulphur LA are off the air. [Continue reading…]

 


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Mike compares four active mag loop antennas

Many thanks to Jon Hudson who shared the following on the SDRplay Facebook page:

In this new video, Mike Harwood compares 4 different active mag loop antenna at various frequencies up to 52MHz using two SDRplay RSPduos which allowed simultaneous spectrum snapshots of the 4 loops in action with real signals.

These are loops from Bonito, Cross Country Wireless, LZ1AQ and Wellbrook.

This is the second of Mike’s antenna comparison videos. He welcomes comments which will help shape the content for future antenna experiments:

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Malahit DSP-2: Dan’s thoughts on external antennas, firmware, and purchase decisions

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


Additional Thoughts on the Malahit DSP-2 

  • Potential for Noise Reduction Using Non-Whip Antennas
  • Latest Firmware Changes

by Dan Robinson

After my last update on the Russia-made Malahit DSP-2, I thought it important to add something about the receiver, as it could well influence those who may be on the fence about purchasing one.

In a series of communications, Georgiy at Malahit team has stressed steps taken to attempt to deal with internal interference seen across the bands.  And he has asserted

that noise spikes lessen if the receiver is connected to a non-whip antenna.

Most of my tests have used whip antennas of various lengths, in various locations indoors and outdoors, because it’s my view that portability is a major attraction of these small SDR receivers.

Continue reading

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Malahit DSP-2 Review Update 3: Dan evaluates the latest hardware version

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


UPDATE NO 3: Malahit DSP-2 (August 18, 2021)

A few weeks ago, I wrote about my experiences with the Russia-made Malahit DSP-2 receiver, and made a recommendation that potential purchasers of the receiver hold off until the design team in Russia made some changes.

Weak points included the SMA antenna connector – specifically the short cable going from the antenna to the PCB board, and sharp noise spikes seen at numerous locations throughout the spectrum from mediumwave up to 30 MHz.

My particular DSP-2 unit went dead after an update to an early version of the 2.10TEST firmware.  At the time, I had spoken via Skype with Georgiy on the Malahit team and kept up a string of communications on the Malahit Telegram channel.

It was not clear to me whether the problem with the first DSP-2 was primarily due to SMA antenna issues or also due to a problem with the firmware update I had applied at the time (it was an early version of 2.10TEST).

My appreciation goes to Georgiy who decided to send a new DSP-2 to me.  This took about 3 weeks from the end of July until just recently when the receiver arrived (though the U.S. Postal Service made the end of that journey quite interesting).

Here are some observations that I hope will help current and prospective owners of the DSP-2: Continue reading

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Malahit DSP-2 Review Update: Dan recommends holding off until issues resolved

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


UPDATE: Malahit DSP-2 (July 24, 2021)

RECOMMENDATION: Hold Off Until Issues Are Resolved

I thought it important enough to write this update to my earlier extensive review of the Malahit DSP-2, the second version of the Russia-made receiver. Earlier incremental updates can be seen on the main article.

In concluding my main review, I spoke about being on the Malahit “train” and “roller coaster” – and my experiences since have shown that to be true.

As noted in one the updates, further testing confirmed the observations of Malahit users that when voltage of a 18650B battery drops below 3.7 v the receiver did indeed shut down. And the battery icon was still showing 50%.

Georgiy at the Malahit team confirmed this as a software bug, and in a test firmware update, the voltage issue was, according to him, corrected. The result, in a test firmware upgrade (2.10) could be seen with remaining voltage displayed in the battery icon itself. But I was unable to confirm that this actually resolved the issue of inaccurate voltage displayed before yet another problem emerged.

After performing the update from 2.0 to 2.10 Test firmware (more on that a bit later)
I thought things were fine until I noticed that all signals had vanished from the Malahit. This applied to the strongest signals from U.S. religious broadcasters, and down through FM.

In a combination of Telegram and Skype chats, Georgiy was extremely helpful – we went over seemingly every possible cause for this problem and focused on the SMA cable which from observing conversations online appears to be an issue in some units.

We went to the point of disconnecting the SMA from the PCB to test if anything brought back any level of signal, which it did not. With my basic knowledge of electronics, I believe that some problem may have developed on the PCB – whether that is directly related to the firmware upgrade process remains unknown.

On the firmware, the Malahit-recommended PC app is SMT32CubeProgrammer, which is easily downloadable, and instructions for the firmware update are on the Malahit You Tube channel. The process and app look difficult at first.

But things get interesting, as they always do, in using these Bootloader apps as I have found on several occasions in trying to upgrade my AFEDRI LAN-IQ.

Instructions on the Malahit You Tube channel direct you to power off the radio, then plug in a micro-USB cable to the receiver and to your PC. The rough Russian translation says push in and hold both main and smaller encoder knobs, and then press power either once or 3 times, and then watch for the LED to go off. The LED actually doesn’t really go off– in the process of the firmware update, flashes on and off.

I managed to get through the process of upgrading – it was quite smooth. The test 2.10 firmware according to Georgiy is supposed to correct the issue with voltage readings, though again I was unable to test this fully because my DSP-2 quite literally went quiet over its entire range.

As of now, and despite the best efforts of Georgiy which I appreciate, I have a dead DSP-2. Whether signal loss was due to some issue with the SMA connector, or whether the firmware process (I reverted back to 2.0 after noticing the signal loss) itself caused something on the PCB to fail, remains unknown.

Given all of this new information, and though I had made no BUY recommendation on my original review, I would have to advise anyone considering a DSP-2 to hold off for a while until the Malahit team is able to thoroughly iron out all the hiccups with the receiver, whether in firmware or hardware. This includes the question of the SMA connector, and the issue of voltage monitoring.

Based on the conversations that were taking place on Telegram, I would also be urging Malahit team to quickly come up with a clear English translation of the Malahit manual, and to review instructions contained in You Tube videos showing the firmware upgrade process.

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