Saturday, December 07, 2013

SDR - Software Defined Radio

Last week I read an article in this months RADCOM by G0CHO about using a DVB-T stick as SDR to recieve all modes from VHF to Microwaves. I was fascinated by the article and also the free software to use with the stick. I have an old stick, but the chip is not suitable for SDR.
I decided to buy a new DVB-T RTL stick, so set about trying to find one on ebay. I was amazed to find a company called 'Cosycave' selling a new and fully tested DVB-T stick complete with leads and all the software required to receive SDR...and the cost?  £13.95!!!

I sent for the package and it arrived from Jersey the next day...too good to be true?

Definately not! The instructions that came with it on the disc is worth gold, very thorough, step by step instuctions on using the software and setting up the stick. Also includes SDR Sharp, an excellent and easy to use piece of software. After going through the initial set up the DVB-T stick worked straight away with SDR Sharp. I was amazed to be able to tune any frequency in all modes with just a tiny stick. Where are the tuned circuits, coils, variable capacitors? How could something so tiny receive everything from broadcast FM stations to Packet, Weather Satellites and Amateur Bands including 70cms and 23cms?

When I first got the stick receiving I listened to a local station on 2m and watched the spectrum waterfall for other stations. It seemed a bit insensitive, but then I realised that there is an RF gain control in SDR Sharp. When I found it I wound up the RF Gain and almost fell off my!
Now I am hooked on this SDR stuff, it has opened up a new dimension that I didn't know about. I thought SDR was expensive and even plug in sticks like the FunCube were not cheap. To think that you can buy the whole SDR set up for 13 quid is fantastic!

Now I am experimenting with weather satellites, with the pack you get software for decoding and displaying the weather pictures from the NOAA satellites. Today I built a 137Mhz Turnstyle Antenna which seems to work well.


Dominic Rivron said...

I read your letter in RadCom and it inspired me to a hunt round the internet for a DVB-T stick myself. I found your blog.

I was just about to buy the same one as you from CosyCave when I saw it said at the bottom that it required a Pentium 4 processor with a 3 GHz clock speed. If so, I don't think my old shack computer is up to the task - and I don't think our Dell laptop boasts a 3GHz clock speed. I'm wondering if these specs are needed for the uses we're putting it to. Any thoughts on this gratefully received!

PS - I also blog (though only occasionally about amateur radio) at

G4AQB said...

Dominic, I think it is a case of 'try it and see' my computer is quite old now and running at 2.2Ghz. It works fine for my purpose ... Best of luck!

Dominic Rivron said...

Thanks. I may well have a go.

By the way, I built an "eggbeater" antenna for weather sats. Plugged it into a handheld and fed the audio into a suitably programmed PC. Great fun. If I get one of these devices I'll try plugging it in.