Category Archives: Software Defined Radio

South American shortwave catches, rarely heard in Europe

Hi there, I thought I would share some DX catches, all of which are rarely reported in Europe and yet I was fortunate enough to catch in Oxford UK, using a couple of different set-ups. The first is Radio Chaski Red Integridad from Urubamba Cusco, Peru, heard using an Elad FDM DUO and Wellbrook ALA1530 active loop antenna (indoors). The two subsequent receptions originate from Brazil; Radio 9 de Julho, Sao Paulo and Radio Transmundial,Santa-maria Camobi, both of which were caught using the venerable Sony ICF-2001D portable receiver and my 200 metre longwire antenna. In all three cases, persistence was necessary whilst optimum conditions of propagation aligned with my listening schedule at home and my less frequent, but regular DX’peditions.

I am soon to deploy a 200 metre Beverage with adjustable termination resistance for nulling ‘rearward’ signals and matching transformers suitable for 75 and 50 Ohm receiver antenna inputs. I hope this will further improve my reception capability on both the MW and SW bands. Another post specific to that project is in the pipeline, but in the meantime, thanks for reading/ watching and I wish you all very good DX.

Direct link to Oxford Shortwave Log for Radio Chaski Red Integridad reception video

Direct link to Oxford Shortwave Log for Radio 9 de Julho reception video

Direct link to Oxford Shortwave Log for Radio Transmundial reception video

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

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London Shortwave’s portable “spectrum capture lab”

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

“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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Tropical Band DXing at home with Elad FDM DUO and Wellbrook ALA1530 active loop

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Recently I have spent a little more time listening out for Tropical Band stations from my shack in Oxford UK, attempting to emulate some of the very nice signals I have previously recorded out on DX’peditions. The obvious problems with this (and they are numerous) include the relatively weak signal strength of many tropical band stations, the ubiquitous blanket of QRM, resulting in generally poor SNR, lack of space for a large antenna……need I go on?! Fortunately, the Elad FDM DUO has proven to be a very senstive and selective receiver, capable of, at times, incredible SNR, coupled with almost limitless signal conditioning options and SSB, SYNC, ECSS etc. Throw the Wellbrook ALA1530 active loop into the mix (not literally!) and you have a very powerful Tropical Band receive set-up. The Wellbrook is able to null most (although not all) QRM in my shack and that really can make the difference between simply observing a carrier and actually hearing audio. Clearly one cannot expect to hear DX at home under heavy QRM as well as you might outdoors, however, the following stations were logged in the past month or so, with respectable signals, with the ALA1530 indoors:

Video links also follow below, thanks for reading/ watching.

Direct link to Oxford Shortwave Log video; Radio Logos 4810 kHz, Peru

Direct link to Oxford Shortwave Log video; Radio Cultura Ondas Manaus 4845 kHz, Brazil

Direct link to Oxford Shortwave Log video; AIR Bhopal 4810 kHz, India

Direct link to Oxford Shortwave Log video; Rádio Educação Rural 4925.2 kHz, Tefé, Brazil

Direct link to Oxford Shortwave Log video; Radio Mosoj Chaski 3310 kHz, Bolivia

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The RTL-SDR V.3 dongle on shortwave: Gary details setup and reviews

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Many thanks to SWLing Post contributor, Gary Wise (W4EEY), for the following review of the RTL-SDR dongle:

Based on your blog post on the Version 3 release of the RTL-SDR dongle I had to buy one. I ordered mine from Amazon for $25, and it came in two days. I have an earlier version of this unit that was VHF and above only. What intrigued me about the V3 was the possibility of HF reception in the Direct Sampling mode (without an up converter). So I had to try it.

I used the RTL-SDR Quick start guide at RTL-SDR.com/qsg. While I did not see any mention of Version 3, I hoped that the software that was linked would be adequate. As I am using a Windows 7 laptop, I downloaded the Zadig driver installer, along with copies of SDR# and HDSDR.

Getting the dongle going was pretty straightforward. And right away I was receiving VHF and above signals. The I/O driver defaults to Quadrature demodulation and this was what is used to receive VHF. But what about HF?

It took me awhile to figure out that you select Direct Sampling in the setup screen for the driver. In SDR# software this is found by clicking on the gear wheel icon.

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Under sampling mode select Direct Sampling (Q branch).

In HDSDR you select the EXTIO icon.

Here you select the Q Input under Direct Sampling.

Note that with both you must use the Q input.

With the telescoping antennas included with the dongle, I received very few signals (of very poor quality). But I had read that the unit can only receive HF with a substantial antenna, so I moved the laptop to my hamshack.

I use an ELAD antenna distribution amplifier for my HF receive antennas.

It was easy to use a spare output from the ELAD ASA15 to drive the antenna input of the RTL-SDR V3.

Wow, what a difference!

First up was international shortwave. Here’s a shot from my Alinco General Coverage receiver on 9955 kHz this morning using my 260′ beverage antenna (pointed toward Europe). S9 on the Alinco S Meter.

And here’s the same signal on SDR#.

There was a delay in the audio coming from the PC versus from the receiver, but other than that, reception was identical. Audio quality was very good.

I then moved to the 20M Amateur Radio band. USB audio demodulation.

The little dongle worked! It is not what I would call my first choice in receivers, but it will demodulate AM and SSB just fine.

I did not try it on CW as I ran out of time.

I also tried the HDSDR software, which worked equally as well (but I think I prefer SDR# for ease of use).

All in all, if you have or can put up a good antenna for HF, the little $25 dongle is in, my opinion, worth trying out.

73,

Gary
W4EEY

Click here to purchase the new RTL-SDR–$24.95 shipped on Amazon.com.

Thank you, Gary, for not only giving a quick evaluation of the RTL-SDR’s HF performance, but for describing how to setup HF reception via SDR# and HDSDR.

Over the years, I’ve gotten probably hundreds of emails from readers who would like to try their hand at SDRs, but were cautious about investing. For many years, a 3rd generation SDR would set you back at least $300-400. At $25 shipped, the RTL-SDR V.3 is an SDR receiver that is accessible to anyone who can afford a fast food meal or a few cups of Starbucks coffee. My how times have changed!

Once I get a few transceiver reviews off of my table, I might do some side-by-side HF comparisons between the RTL-SDR and a few of my other SDRs.