Tag Archives: Portable SDR

Coastal DXing with the AirSpy HF+ Discovery and a homebrew passive loop antenna

Last week, we packed the car and headed to coast of South Carolina.

The trip was a bit impromptu but through the creative use of hotel points, we scored a two bedroom ocean front unit with a fantastic little balcony.

The vacation gave me an excuse to test the new passive loop antenna my buddy Vlado (N3CZ) helped me build recently.

The loop design came from AirSpy’s engineer and president, Youssef Touil.

This passive mag loop takes advantage of the new AirSpy HF+ Discovery‘s exceptionally high dynamic range. Youssef had reported impressive results, so I had to build one.

Vlado had a length of Wireman Flexi 4XL that was ideal for this project. The only tricky part was penetrating the shielding and dielectric core at the bottom of the loop, then tapping into both sides of the center conductor for the balun connections.  Being Vlado, he used several lengths of heat shrink tubing to make a nice, clean and snag-free design.

The results were truly exceptional. I spent most of my time on mediumwave from the hotel balcony because I was determined to catch a transatlantic signal.

Check out the spectrum display from my Microsoft Surface Go tablet:

Our ocean front hotel was inundated with noise, but I still managed to null out most of it and maximize reception using the passive loop. I simply suspended the loop on the balcony rocking chair–not ideal, but effective and low-profile.

Want to take a test drive?

If you’d like to experience this portable SDR setup, why not tune through one of the spectrum recordings I made?

Click here to download the spectrum file [1.7GB .wav].

The recording was made on November 17, 2019 starting around 01:55 UTC–I chose it at random and have yet to listen to it myself. You’ll need to open this file in AirSpy’s application SDR# or a third party SDR app that can read AirSpy .wav files.

Stay tuned…

I’m writing an in-depth report of the HF+ Discovery, my experiments with this setup and AirSpy’s soon-to-be-released passive loop antenna for the January 2020 issue The Spectrum Monitor magazine. Spoiler alert: I am truly impressed with the wee little AirSpy HF+ Discovery. It’s a powerhouse!


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The new Malahit-DSP: A portable all-in-one wideband SDR receiver

Many thanks to SWLing Post contributor, H. Garcia (PU3HAG), who writes:

Hey Thomas,

Some very exciting news on the topic of portable all-band receivers comes from Russia! A group of engineers have just released for ordering the new Malahit-dsp. And it’s truly impressive! Picture an Icom IC-R8600 with the size of a Sony 7600G!

It seems it all started in June this year. Back then, RX9CIM George posted a note in QRZ.com forum about a new project he had been working of a standalone, SDR-based, all-band, all-mode receiver called Malahit-dsp.

Fast forward to November and it seems the project is finally complete as new posts started to bubble up in Youtube and in Russian forums. George is now taking orders of the Malahit DSP.

I can’t read Russian, but with the help of Google Translator, we can find some interesting details:

The project authors are RX9CIM George, R6DAN Vladimir and R6DCY Vadim. It seems their goal was to design a low-cost portable SDR radio, using only easily obtainable components and to become the natural successor of the popular Degen and Tecsun radios.

Technical Specifications

  • 1 MHz to 1000 MHz.
  • Bandwidth 160 kHz.
  • Modulation types AM, WFM, NFM, LSB, USB.
  • Powered by one Li-ion cell.
  • Consumption up to 300 mA
  • Main chip ARM STM32H743VIT6 MCU High-performance and DSP with DP-FPU, ARM Cortex-M7 MCU with 2MBytes Flash, 1MB RAM, 400 MHz CPU
  • Printed circuit board is used four-layer, factory-made; for purchase, refer to RX9CIM. malahit_sdr@rambler.ru

PCB only: ~ USD 17.22
Finished receiver delivered inside Russia: USD 195.65

From the forum, there is also this important note: “Attention! Fraud/Scammers detected! You can purchase components or finished devices from George only ”

It seems the project is open source, the schematic, PCB and software are available to download.

I really hope this receivers becomes popular and available world wide. I also hope this new project “shakes” a bit the industry of shortwave receivers. Since the Degen 1102/03, Tecsun 450/600, Tecsun PL310/880, we have been seeing only iterations of the same designs.

Pages

Group dedicated to Malahitdsp
https://vk.com/malahitdsp

Recent discussion on Malahit, annoucement of ordering is now available, pictures and videos
http://hamforum.ru/viewtopic.php?t=193

Videos

Video 1: Shows the soldering of large components (encoders, speaker, SMA jack) on the radio board and installing it into the metal enclosure. Next a demo of receiver working. Prepared by Sergeyenkov Alexander:

Video 2: It shows a bit of the manufacturing process and demonstrates how one can build the receiver at home using kit pre-made board and components acquired in AliExpress. Also includes a test of the receiver barebones. Prepared by R2AJI Vladimir on his YT channel “HAM Radio Channel”

Wow!  Thank you so much for sharing this!  The Malahit-DSP looks like a fantastic little receiver–I especially love the fact that it has a backlit color touch screen with both a responsive spectrum and waterfall display. It also looks and sounds like the built-in speaker is of decent quality and the audio amplification is more than adequate.

I’ll see if I can get one to evaluate. Thanks again for the tip!

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London Shortwave’s innovative PocketCHIP-powered field portable SDR

Many thanks to SWLing Post contributor, London Shortwave, who recently shared his latest SDR project: a field-portable, ultra-compact, SDR spectrum recording system based on the PocketCHIP computer.

London Shortwave has built this system from the ground up and notes that it works well but is currently limited to the FunCube Dongle Pro+ at 192 kHz bandwidth. There is no real-time monitoring of what’s being recorded, but it works efficiently and effectively–making spectrum captures from the field effortless. The following is a video London Shortwave shared via Twitter:

Click here to view via Twitter.

The PocketCHIP–the device his system is built around–is a $69 (US) handheld computer with color display:

Click here to view the PocketCHIP website.

I think this field portable SDR system is absolutely brilliant!

Homegrown innovation

London Shortwave has done all of the coding to make the FunCube Dongle Pro + work with the PocketChip computer. Even though live spectrum can’t be monitored in the field, the fact that it’s making such a clean spectrum recording is all that really matters.

All London Shortwave has to do is head to a park with his kit, deploy it, sit on a bench, read a good book, eat a sandwich, then pack it all up. Once home, he transfers the recording and enjoys tuning through relatively RFI-free radio.

A very clever way to escape the noise.

The kit is so incredibly portable, it would make DXing from any location a breeze. You could easily pack this in a carry-on item, backpack or briefcase, then take it to a park, a national forest, a lake, a remote beach–anywhere.

What I really love about this? He didn’t wait for something to be designed for him, he simply made it himself.

Thanks again, London Shortwave. We look forward to reading about your radio adventures with this cool field SDR!

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London Shortwave’s portable “spectrum capture lab”

SWLing Post contributor, London Shortwave, just posted a photo of his portable SDR setup on Twitter and noted:

LondonShortwave-Portable-SDR

“Portable spectrum capture lab back in operation. Grabbing the grey line hour on the 49 mb. Listening to Radio Fana!”

Wow!  I love this go kit!

Looks like London Shortwave is running an AirSpy with Spyverter via SDR# on his Windows tablet.

Having played a lot of radio in the field, I think what’s great about this setup is the fact it’s all contained and properly laid-out inside the padded case. Simply open the case, deploy an antenna, and you’re in business! With all components inside the case, there’s much less chance a connector, battery, cable or SDR will be left in the field accidently. Quick deployment and quick pack-up time; that’s what it’s all about!

Great job, London Shortwave! I’m happy to see you’re back in the park capturing spectrum and logging DX!

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Video: SDR Touch demo on Android device using SDRplay RSP

Fullscreen capture 4242016 10946 PM

(Source: SDRplay via YouTube)

Click here to view on YouTube.

This demonstrates turning an Android Tablet (or Android Phone) into a highly portable comms receiver or spectrum analyzer operating from Long Wave to Microwave (10kHz to 2GHz) – using SDR Touch and the SDRplay RSP www.sdrplay.com

To be a beta tester simply go to https://play.google.com/apps/testing/ and follow the instructions – the SDR Touch author welcomes feedback on https://www.facebook.com/SdrTouch/ – your chance to influence the way this amazing software can get better and better.

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The Siru Innovatios SDR20 adds new features

Siru-Innovations-SDR20-1

Many thanks to Jarkko Mäkivaara with Siru Innovations who writes with the following update:

We have added some new features to our SDR20 portable radio!

Please see the video [below] for a demonstration of the following features:
* Smooth zoom in FFT/waterfall view
* Adaptive menu
* Frequency memory with snapshot pictures of signals
* Sliding effect between views
* Keyboard beep
* FM broadcast receiver
* Example of Ham radio transceiver with Narrow-FM mode
You also might got the email sent out Today where this is in HTML format.

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LondonShortwave: “Scanning the skies”

Fullscreen capture 7302015 124403 PMMany thanks to SWLing Post contributor, LondonShortwave, who shared (via Twitter) this video with recordings made with his portable SDR in a London park:

Brilliant recordings, LS, and amazingly QRM-free!

You can follow LondonShortwave on his blog and via Twitter.

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