New gadget in the shack: an RFSPACE SDR-IQ

January 4, 2010 | Amateur Radio | By: Mark VandeWettering

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

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Comments

Comment from Alan Yates
Time 1/5/2010 at 3:04 pm

Mark,

Too cool! I want one.

What is the API like for writing your own apps?

The SDR-14 looks interesting, especially its triggering feature, but the SDR-IQ is a nice neat package all powered off the USB and fairly cheap for what it looks like it can do.

Regards,
Alan

Comment from Mark
Time 1/5/2010 at 3:23 pm

You can get the API from http://www.moetronix.com/svdownload.htm (doiwnload the SDRIQinterfaceSpec100.pdf) for more information. Basically, it looks like a serial port that you send packeted commands to, and it responds with data packets. The actual number of commands is pretty small, and seem to be reasonably well documented. The one complication is that to control the decimation, you need to poke values directly into the digital decimator chip (an AD6620, if memory serves, my docs are at home at the moment). The decimator has multiple stages of filtering, and you can control the shape of each filter separately.

It’s a brand new gadget for me, I haven’t tried any of this yet, but stay tuned for future updates.

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