Yearly Archives: 2018

Radio enthusiasts receive images from the Longjiang-2 in lunar orbit

Image received by astronomer Cees Bassa (@cgbassa) using the Dwingeloo Telescoop

Many thanks to SWLing Post contributor, Eric McFadden (WD8RIF) who shares the following story from The Planetary Society:

Earlier this week, on October 10, radio amateurs all around the world worked together to get the Chinese Longjiang-2 spacecraft to take an image of the Earth and the far side of the Moon. Radio commands were generated by MingChuan Wei in China, transmitted to the spacecraft by Reinhard Kuehn in Germany after which they were received by the spacecraft in lunar orbit. In turn, the spacecraft transmitted the image back to Earth, where it was picked up by radio amateurs in Germany, Latvia, North America and the Netherlands.

Since June this year, the Chinese Longjiang-2 (also known as DSLWP-B) microsatellite has been orbiting the Moon. The satellite is aimed at studying radio emissions from stars and galaxies at very long wavelength radio waves (wavelengths of 1 to 30 meters). These radio waves are otherwise blocked by the Earth’s atmosphere, while the lunar environment offers protection from Earth-based and human-made radio interference. Longjiang-2 was launched to the Moon together with an identical twin, Longjiang-1 (DSLWP-A), together acting as a radio interferometer to detect and study the very long wavelength radio waves by flying in formation in lunar orbit.

Besides the scientific instruments, both Longjiang satellites carry a VHF/UHF amateur radio transmitter and receiver (a transceiver) built and operated by the Harbin Institute of Technology (in Chinese). The Longjiang-2 transceiver also includes an onboard student camera, nicknamed the Inory Eye. The Harbin team built on experience gained with the Earth-orbiting LilacSat-1 and LilacSat-2 nanosatellites, which allow radio amateurs to receive satellite telemetry, relay messages and command and download images taken with an onboard camera.

While receiving signals from satellites in low Earth orbit requires only relatively simple antennas, doing so for satellites in orbit around the Moon (a thousand times more distant), is much harder. To this end Longjiang-1 and 2 transmit signals in two low data-rate, error-resistant, modes; one using digital modulation (GMSK) at 250 bits per second, while the other mode (JT4G) switches between four closely spaced frequencies to send 4.375 symbols per second. This latter mode was developed by Nobel-prize winning astrophysicist Joe Taylor and is designed for radio amateurs to relay messages at very low signal strengths, typically when bouncing them off the surface of the Moon.

[M]any radio amateurs have been able to receive transmissions from Longjiang-2. Usually, the transceiver is powered on for 2-hour sessions at a time, during which GMSK telemetry is transmitted in 16-second bursts every 5 minutes. After some testing sessions in early June, the JT4G mode was activated, with 50 second transmissions every 10 minutes.

Specialized open source software written by MingChuan Wei and the Harbin team enables radio amateurs to decode telemetry as well as image data and upload it to the Harbin website.

The JT4G mode has allowed radio amateurs with small yagi antennas to detect signals from Longjiang-2 (using custom software written by Daniel Estévez).[…]

Click here to read the full article at The Planetary Society.

This is fascinating, Eric! Thank you for sharing. It would be amazing fun to grab one of these Lunar signals! Anyone up to the task?

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NHK WORLD-JAPAN changes reception report contact address

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Many thanks to SWLing Post contributor, Lilian Putina, who shares the following message from NHK World-Japan:

Dear Listeners of NHK WORLD-JAPAN Radio services,

Thank you very much for listening to NHK WORLD-JAPAN Radio services.

We are writing to notify you that the NHK WORLD-JAPAN e-mail address ([email protected]) will be unavailable from October 20. Replies to this e-mail address will not be received/reviewed.

Hereafter, please send your reception reports/messages via “Contact us” form on each language website.

For English and Japanese services, please send via “Contact Us” form at https://www.nhk.or.jp/nhkworld/en/contact/

We appreciate your cooperation, and hope you will continue to enjoy NHK WORLD-JAPAN.

Regards,
NHK WORLD-JAPAN
http://www.nhk.or.jp/nhkworld/

Thanks for sharing this tip, Lilian!

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Will the cost of radios increase for US consumers?

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In the past few months, I’ve received a number of questions from our readers in the United States regarding the potential for radio prices to increase.

Why could prices increase? Keeping in mind, I’m no expert in this field (seriously–!) I understand there are at least three factors that could influence prices:

China

As of today, almost all portable shortwave radios on the market are made in China. In fact, I can’t think of a single portable broadcast receiver that isn’t made in China although I’m sure there are some made in other parts of the world.

Tariffs

This year, the US administration has placed tariffs on a long list of consumer electronics produced in China and elsewhere–the list could grow. Radio receivers could fall into some of the affected product categories. Click here to read the full current list (PDF). Some ham radio retailers have notified their customers to expect price increases (BridgeCom Systems comes to mind).

Postage

The US plans to withdraw from an international postal treaty that has allowed Chinese companies to ship small packages to the United States at discounted rates. If this withdraw were to happen, it’s my understanding it would primarily affect direct postal shipments that are now prevalent from sellers on eBay, Amazon.com, Alibaba and similar. This might mean either the end of “free shipping” from China-based retailers who’ve relied on inexpensive ePacket shipments, or product prices might increase to compensate for the added expense. This shouldn’t directly affect the price of parcel carriers like UPS, DHL or FedEx.

So what’s the takeaway?

In general, sure…I would expect radio prices to increase.

I don’t think it’s a time to panic as there are a lot of market forces at play here. I would personally anticipate price increases anywhere from 10 to 25 percent.

If you’ve been considering one of the pricier full-featured portables, you might nudge yourself in the direction of ordering one in the near future rather than later. (Note: Your friendly radio enabler suggests you use this as an excuse to grab another set! Go get it!). 🙂

Again, I’m not panicking. So far, I haven’t noticed any significant changes in pricing at the major online retailers. When price increases hit the streets, I doubt they’ll be steep enough to discourage us from buying the occasional radio.

One more thing…

I’ll admit that I’ve been reluctant to bring up this topic on the SWLing Post as it’s politically-charged. So keep in mind…

This is a website where we celebrate our love of all things radio, not a space for name-calling, trolling, or heated back-and-forth littered with vulgar language. Our moderators do their best to pluck those comments when they manage to make it through our comment filters. If you’re looking for an outlet to do those things, the web is chock-full of sites that will indulge you.

Over the years, many of you have written and thanked me for providing a safe haven from the drama that’s so prevalent on otherwise wonderful websites. You’re most welcome.

Keep in mind: the SWLing Post is my refuge, too, and I’m keeping it that way!

Thank you all for understanding.

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Joseph Hovsepian: Montreal’s “Radio Doctor”

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Many thanks to SWLing Post contributors Scott Gamble and Bill Mead who both share the following story via the CBC News:

Joseph Hovsepian says he is part of the last generation that knows how to repair electronics

Joseph Hovsepian has been repairing? radios for so long that he claims that he can sometimes smell the problem.

“When I pick up a radio, I turn it on or I plug it in and the way it smells, the way it sounds or doesn’t sound, the way it crackles and fades away, all these things are recorded in my brain and I know exactly how to start and how to fix it,” he said.

Since 1960, Hovsepian has been fixing radios, turntables and other electronic gadgets from his Parc Ave. repair shop.

The 79-year-old sees himself as part of the last generation of people trained in the art of repair.

“We have lost the ability to touch things, fix things, repair them and feel good for doing it,” he said.

For almost his entire life, Hovsepian has been tinkering with radios. He built a crystal radio when he was 12, and his first tube radio at 15.

[…]He believes that today’s electronics lack the warmth that the old radios offered. Hovsepian said smartphones look dead to him compared to old technology.

“Even the sound of the old radios, a little scratch here, a little scratch there…This is radio.”[…]

Click here to read the full article at CBC News.

This is a charming story and I think Post readers can certainly understand why radio seems to be in a class of its own. I feel very fortunate that I’m friends with two people who repair radios for others, my buddy Charlie (W4MEC) and Vlado (N3CZ). Both are kind enough to show me the ropes as they troubleshoot problem sets.

Post readers: Do you live somewhere with a radio repair shop? Have any readers ever visited Mr. Hovsepian’s shop in Mile End? Please comment!

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Stefano invites you to experiment with DRM (Digital Radio Mondiale) over IP

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Many thanks to SWLing Post contributor, Stefano Mollo (VK6WFM), who writes:

I have been lately experimenting with DRM 30, with the aim of coming up with a cheap solution to get on air for next to no $$$, for small, local broadcasters that would either go pirate on FM or would not go at all due to the impossibility here in Australia to get a proper FM license at a cost that does not involves selling a kidney (or two)!

I am a ham radio operator, so I turned my attention to DRM30; [the DRM application] DReaM has the capability of acting as a transmitter as well, so I started experimenting.

Click here to download DReaM via SourceForge.

I was very successful at transmitting a DRM30 / 10 kHz signal with a $ 0.50 TX module otherwise intended to transmit data with an Arduino. The signal was received with an SDR + HDSDR + Virtual Audio Cable + DReaM in reception mode.

So far, so good; with this experiment I realised that DRM 30 can, in fact, yield excellent quality at ANY frequency (as I used the 433Mhz LIPD range in my experiment) or better said, with any medium, as long as it is linear enough to transport the DRM signal.

I wanted to find a way to show the World – literally – what can be achieved with DReaM in TX mode…for free!!!

So, after some trial and error, I have set up the system below which allows anyone in the World to “tune in” my “DRM30 radio station” and listen to my DRM30/18 kHz signal, in full blown stereo. Quality is exceptional, and just imagine to send DReaM’s signal to a proper transmitter instead of streaming it over the internet ….

So…point your VLC Media Player (on Windows) to stream from:

…then pipe VLC’s output to DReaM’s input via Audio Cable (or any other Virtual Audio Cable you like).

In DReaM, select the audio cable output as the sound card’s signal input device:

Then select L+R as Channel:

Set the sample rate to the highest value:

One more thing you need to set is the “Channel Estimation: Time Interpolation” parameter to Linear; this is very important!

After few seconds you should be able my test signal, in full stereo, streamed from a PC running DReaM in TX mode, whose output is then captured by MB Recaster and streamed to an ICE Cast server I have in the Cloud. Note that no particular configuration was needed on the ICE Cast server, at all.

This is an example of what can be achieved on a solid transmission channel with DRM30 and only 18 kHz bandwidth (i.e. the normal bandwidth of an AM channel).

One can achieve the same exact audio quality using any channel linear enough to transport an 18 kHz wide DRM30 signal. It doesn’t matter the frequency, or the physical medium per se.

[…]My aim with this experiment is not to send DRM over IP; there are much simpler ways or streaming audio over IP.

Rather, my aim is to demonstrate what can be achieved with 18 kHz +DRM30 on any frequency and on any medium (which, could be for example the electrical distribution overhead lines …. just saying …. 🙂 ).

If only the local regulator would support this, instead of enforcing draconian regulations … such as the restriction of just 6 kHz on shortwave.

Please share your thoughts.

Fascinating experiment, Stefano! Thanks for sharing!

Post readers: If you’re in the mood to do a little experiment, let us know if you’re able to decode Stefano’s 18 kHz DRM30 broadcast over IP! Please comment!

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Tommy (N1SPY) on monitoring airplane communications

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Many thanks to SWLing Post contributor, Ivan (NO2CW), who writes:

If anyone is interested in monitoring aircraft communications across HF, VHF and UHF, Thomas, N1SPY put together a demo video of what you can hear and how: