Daily Archives: 1/4/2010

New gadget in the shack: an RFSPACE SDR-IQ

Well, I got a new gadget in the mail today: an SDR-IQ from rfspace.com. It’s a cute little gadget: a general purpose receiver that can deliver the quadrature signals for any 192Khz of the spectrum anywhere from 100Hz (yes, Hz) to 30Mhz. It is a small black box, with only three connectors: a USB, a regular serial port (used for rig control) and a BNC port for attaching an antenna. I fired it up, and right away started to find interesting things: for instance, here is the frequencies around 5.8Mhz:

2010-01-04_2222-cuban-numbers

If you look carefully, you can see that this is actually an AM signal. The carrier and a couple of sidebands are visible to each side of the received signal. If you click on the signal, and select the AM demodulator, you get the following audio:

AM modulated Morse code at 5.8Mhz, recorded around 06:30, Jan 5, 2010

A quick google of the web indicates that this is a Cuban numbers station. Pretty nifty, and probably never would have discovered it without using the RFSPACE SDR-IQ.

You’ll be hearing more about this gadget in the future.

Addendum: I’m not the only person (obviously) to hear these guys.


httpv://www.youtube.com/watch?v=P_YxgDt8aM0

30m Subharmonic I/Q-SDR Receiver

Over on NT7S’s Ripples in the Ether blog, he presents a link to a project by Joachim, DL1GSJ, a very nifty little SDR designed to operate near the 30m QRSS watering hole frequncy. It uses pair of subharmonic mixers, whose operation I admit I don’t completely understand, but I’m bookmarking the circuit for later consumption.

de draaggolf     ~~~~~: 30m Subharmonic I/Q-SDR Receiver.