Author Archives: Thomas

Silphase R1 videos and information about power and antenna ports

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We’re starting to get a little more info about the recently posted Silphase R1 SDR receiver. At this point, the radio isn’t in production and is obviously only in a prototype stage so there are a lot of question marks–including if it’ll ever come to fruition. The pandemic is obviously not an ideal time to launch and produce a new high-end radio. I, for one, certainly hope they do!

Many thanks to SWLing Post contributor, Mark Hirst asked Silphase about R1 external antenna support and power options. A Silphase representative replied:

“We are constantly redesigning the rear panel receiver Silphase R1, so we
can say for sure that there are 4 connectors – antenna F-type connector,
12.6 V power/charging, RJ-45 and USB”

And thanks to SWLing Post contributor, Paul, who received the following info from Silphase:

You can watch real videos on our YouTube channel.

https://www.youtube.com/channel/UCQN8YbKULHlkA4KBFt76Hhg

Sample videos:

Click here to view all of the videos on the Silphase YouTube channel.

As we learn more about the Siplase R1, we’ll publish it on the Post with the tag: R1.

Converting Tecsun signal meter numbers into five strength units?

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Many thanks to SWLing Post contributor, Chris Rolfe (M3OZP), who writes with the following inquiry:

Don’t know if anyone can help.

I have a Tecsun PL-880, and it shows signal strength in db. How can I work out the signal strength as 1 to 5? All my other radio have 1 to 5 signal strength meters which is what I have always been used to.

Many thanks.

Chris Rolfe
M3OZP

Thank you for your question, Chris. The signal meter on the PL-880 and a number of other late-model Tecsuns that use similar DSP chips share the signal display which indicates both the signal strength and signal-to-noise ratio.  I believe the dBu number indicates the conducted voltage across the receiver’s internal resistance.

It’s perhaps one of my quirks, but as a listener I actually pay little attention to signal displays on portables unless I’m evaluating signal strength for a report or even using it to locate a local noise. Converting those numbers into an S1 to S5 number is simply something I would do by “guesstimating.” Yeah, not terribly scientific.

There are folks in the SWLing Post community who can do a much better job explaining the readout and how to interpret/convert signal strength across the MW, SW and FM bands.

Post Readers: Please comment if you can shed some light on simplifying signal strength for Chris.

Giuseppe’s reception of the LRA36 test broadcast

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Photo from the Argentine Antarctic Base (LRA36) – Source: RAE

Many thanks to SWLing Post contributor, Giuseppe Morlè (IZ0GZW), who shares the following:

Dear Thomas

Here is the link of to video regarding the transmission of LRA 36 in USB mode Saturday July 25, 2020 from 17.00 UTC on 15.476 MHz.

A good result if I think it was almost impossible to listen to it with the sun still high … the place where I listen, in Formia, Italy, is really excellent.

73. Giuseppe Morlè iz0gzw.

Thank you for sharing this, Giuseppe! I’m always impressed with the DX you catch there at your location in Formia! Grazie e ciao!

NASA’s SCAN testbed was an orbiting multi-function SDR

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SCAN Testbed (Source: NASA)

Many thanks to SWLing Post contributor Dan (VR2HF) who writes:

“This looks like the world’s most expensive SDR to me. And a little mysterious. Like quantum computing!”

(Source: NASA)

Space Communications and Navigation (SCAN) Testbed

The SCAN Testbed, formerly known as Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT), served as a test facility for NASA research on radio communications and the Global Positioning System (GPS).

SCAN Testbed on International Space Station (Source: NASA)

The SCAN Testbed was launched on July 20, 2012 on a Japanese H-IIB Transfer Vehicle and installed in the International Space Station to provide an on-orbit, adaptable software-defined radio (SDR) facility with corresponding ground and operational systems. This permitted mission operators to remotely change the functionality of radio communications through software once deployed to space, offering them flexibility to adapt to new science opportunities and recover from anomalies within the science payload or communication system.

The SCAN Testbed payload was used to conduct a variety of experiments with the goal of further advancing other technologies, reducing risks on other space missions, and enabling future mission capabilities.

After seven successful years, and more than 4,200 hours of testing, it was decommissioned June 3, 2019 as it burned up in the trunk of SpaceX CRS-17 upon reentry into Earth’s atmosphere.

To learn more:
Communications Testbed Leaves Legacy of Pioneering Technology 
2019 Space Technology Hall of Fame: Ka-Band Software-Defined Radio (SDR)/Harris AppSTAR™ Architecture
NASA’s Space Communications Testbed
Unique Testbed Soon will be in Space
SCAN Testbed Celebrates One Year Anniversary
Glenn Research Center SCAN Testbed

Thank you for sharing this, Dan! I had never heard of the SCAN testbed. I can only imagine what it might have been capable of accomplishing from orbit. I dare say there are even more powerful SDRs orbiting the planet at this moment!

Finally confirmed reception of LRA36 Radio Nacional Arcángel San Gabriel Antarctica

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For years now I’ve attempted to get decent reception of LRA36 Radio Nacional Arcángel San Gabriel in Antarctica. At times, I’ve been able to barely hear their AM signal here in North Carolina–at least, see it as a faint line on my spectrum display and barely hear audio rise above the noise. But in truth I could never confirm anything more than “male voice” and “music” thus never bothered with a report in good faith.

Recently, we’ve posted announcements for a series of test broadcasts from LRA36 in single sideband (SSB). Two weekends ago, I couldn’t receive a single inkling of their signal, but this past Saturday, I finally heard the station well enough to submit a detailed report and recording in confidence.

I had actually set my SDR to record 20 kHz of spectrum at home while I made my first CW POTA activation at the nearby Blue Ridge Parkway. A pop-up storm chased me away from the POTA site and it worried me that I had left my SDR running and connected to the antenna. Fortunately, none of the small thunder storms were directly over my home. Although there was heavy QRN due to local pop-up thunderstorms, their signal was there.

The following sample recording starts at 17:51 UTC  (July 25, 2020) on 15476 kHz.  It’s weak signal DX for sure, but interpretable. I made the recording with my WinRadio Excalibur SDR hooked up to a large Skyloop antenna. This clip starts with the song  Juana Azurduy by Mercedes Sosa:

I’m so chuffed to add the LRA36 QSL to my collection! Broadcasting in SSB made all the difference!

Have you successfully logged LRA36 from your home?  Please comment!

Radio Globe: A handy way to explore the world of Internet radio

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Many thanks to SWLing Post contributor, Dennis Dura, who shares a link to this fascinating project on the excellent Hackday site:

[…]RadioGlobe lets the user tune in over 2000 stations from around the world by spinning a real globe. It works by using two absolute rotary encoders that each have a whopping 1024 positions available. One encoder is stuck into the South Pole, and it reads the lines of longitude as the user spins the globe.

The other encoder is on the left side of the globe, and reads whatever latitude is focused in the reticle. Both encoder are connected to a Raspberry Pi 4, though if you want to replicate this open-source project using the incredibly detailed instructions, he says a Raspberry Pi 3 B+ will work, too.[…]

Just check out this video of Radio Globe in action!

I love it. It’s like a physical version of the amazing Radio Garden website and app.

Hackaday notes that if you want detailed information about this project, the designer made a series of vlog posts about the build. Click here to check it out on his website. Click here to read through build details on Instructables.

Thank you for the tip, Dennis!