The Case for Preppers Using Software Definied Radios for Monitoring.

Started by gil, May 28, 2015, 11:35:43 pm

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I am not a big fan of SDRs... Or should I say, not a fan of computers in a TEOTWAWKI situation. My KX3 was an SDR and a great radio. As you might know, an SDR is a radio which relies on computer software for some of its functions. The computer can be inside the radio itself, or your garden-variety laptop. So, the SDR has in my opinion a major disadvantage, that of needing a fragile, power-hungry, bug-prone computer to function. However it has some distinct advantages...

Signal intelligence is very important to your safety. That means listening to the radio 24/7. Obviousely, if you are alone or only a few people, you can forget about it. Signal intelligence with traffic analysis would require probably a least two people constantly scanning the airwaves; one on HF and below, and another one on VHF and above. That means at least six people rotating in front of two computers/SDR setups. Why SDRs?

SDRs are cheap, and have very broadband receivers. They have low current draws and can run on batteries for a long time. The computer displays a "waterfall," making it very easy to find signals. You can scan a whole band very quickly.

A very common type of SDR is the SoftRock:
For VHF and above, a $20 TV dongle works very well. See:

Some SDRs allow transmitting as well, at QRP (low power) levels.

The issue is to power, protect and maintain a computer for the task. Of course the whole setup would most likely be a fixed base operation. Your group radio operators should be pretty busy scanning the radio waves for traffic at all times. You can't easily power regular radios for that long without a generator, but a couple SDRs and low-current netbooks could rely on solar power and a battery at night.

I will not elaborate much further here. Google and Youtube are your friends..   ???

My plan is to get a Softrock Ensemble RXTX or Peaberry if the kits come back (sold-out), to use for weatherfax reception and QRP digital modes like PSK31. I don't want to draw 2A to listen to the news on AM radio... If I need power to send an email through HF, I have an Icom IC-M700 with 150W. I have a small 12V EePC with Linux Mint installed to run the FlDigi program and SDR software like Gqrx.

In a real end-of-the-World situation I believe maintaining such a setup and routine would be extremely difficult. If however I was part of a group with enough man power and the means to finance the equipment, I would definitely consider it. A whole SDR station with laptop should cost less than $500, excluding power supply, and fit in a medium pelican case.

You don't need a license for listening and the equipment is cheap since you already own a computer... For less than $100 you can be up and running, and listen to all kinds of neat transmissions on HF, LF or VHF/UHF.



Awsome post, Gil. I've been considering getting one of the RTL dongles. It's nice to know you can setup a monitoring station, essentially on the cheap.

It's good to see your RSS feed running again. Missed you guys.


 ;D Sometimes I put the radios down and do something else for a couple months. The site has been more active lately. It comes in waves...