Wednesday, April 18, 2012

RTL-SDR: a really cheap, wideband SDR

One of the latest buzzs in the SDR world is the RTL-SDR Project.

The idea is to use the cheap (they used to be below US$11 and now start at US$20) Digital TV (DVB-T) receivers, which are intended to be used with PCs and have a USB interface.

 These are the innards of one of these units:

The compatibility list is expanding and, currently, accessible here:

What you get is a 64 to 1700MHz (*) receiver, with an amazing sample rate of 3.2MS/s (compare it to your soundcard!), a resolution of 8 bits/sample (not that great but enough for lots of purposes). And the best: software support for GNU Radio, Winrad, HDSDR, ... So far, there are decoders implemented for AM/FM, GSM, P25, ADS-B, TETRA, GMR, GPS, etc.

(*) (sometimes even more; there are some gaps at 1.2GHz or so) 

You can check the latest news about this project here:

It seems that all started here:

The way to integrate these receivers with a common SDR program, as Winrad, HDSDR, WRplus or other Winrad derivatives, is by using an external DLL, which can be found here:

There are already plenty of YouTube videos showing how they work. It is still a work in progress so don't expect to get them going withouth glitches but, at that price, it is worth the work :-)

I have got a couple units to experiment. I will publish here my results as soon as I get them working. This is what I got for less than US$11. The small box is the receiver!

Best regards and good luck with your SDR experiments!


Thursday, March 1, 2012

Flex-1500: QRP is an alternative

Last weekend I was able to contact an Special Event station, on 80m, using just the 5W my Flex-1500 provides. I had already logged the contact an hour earlier using a 200W rig (my Yaesu FTdx-5000MP) but I was curious about using QRP to do it, so I tried. And it worked :-)

So, yes, with patience, this small QRP rig works wonders.


Tuesday, July 19, 2011

The beginning: SoftRock RXTX 6.2

This was my first SDR, built in December 2008, and was quite a surprise for me, as it received beautifully.

I got it as a kit from Tony KB9YIG:

I carefully assembled it:

and mounted it inside a recycled Ethernet switch box, as you can see here:

Here you have a sample of reception with Rocky program:

So that was my beginning with SDRs!


Monday, July 18, 2011

PowerSDR-UI: a great idea by DH1TW

One of the main problems found by hams when they approach to SDRs is the User Interface, as they are used to knobs and buttons and not to click with the mouse. But this is no longer a problem, thanks to Tobias DH1TW. Please, take a look at his PowerSDR-UI Project at:

There is also a YahooGroup devoted to this interesting project at:

Hope this helps!



I should confess that I am addicted to SDRs... Yes, I am hooked with Software Defined Radios. I think they are not only the future but the present of Amateur Radio.

I began with the tiny SoftRock SDR, exactly with a RXTX 6.2 for 40/80m. This was quite a discovery, as it opened (literally) my eyes to a new radio experience. Since then, I have got several other SoftRock kits along several assembles SDRs, as the RFSPACE SDR-IQ, a Flex-5000A, a FUNcube Dongle and, just a week ago, a Flex-1500. I am now toying with another idea: to get an HPSDR kit.

So, yes, I am addicted to SDRs!

My idea of this BLOG is to show my adventures with SDRs as they may help to other people.

Comments welcomed!