Testing Your faraday Cage Using and SDR Computer Controlled "Radio"

stock here: This is a good article, he states the attenuation levels as much higher than more reputable

sources do. See the image, a 50dB reduction is listed as 316 times reduction in signal strength, he claims it is a reduction of 100,000 times! 

I suggest you buy this book, see author and title at bottom. 

The SDR radio is very interesting, I bought one on Amazon for $42, the one he mentions is obsolete. 

from the article

https://codegreenprep.com/2016/06/testing-effectiveness-faraday-cage/

Test 3 – Walkie Talkie and SDR

Good news.  You can actually do a very accurate test of the efficiency of your cage with very inexpensive items.  You want to have a walkie-talkie to place inside your cage, and use a SDR to measure the signal strength, accurately, on the outside.

For the walkie-talkie; if you don’t have a bunch of them already, get a Baofeng UV-5R.  While it is some years since we reviewed these lovely units, and while there have been later models released, the standard UV-5R, at a cost of around $30 each on Amazon, still remains an unbeatable value and excellent performer.  Tune it to a frequency around 145 – 155 MHz, it doesn’t really matter what.  You could tune it down to a lower frequency (they work down to 136 MHz) but best to keep it around the radio’s ‘sweet spot’.

But what is an SDR?  The acronym stands for ‘Software Defined Radio’.  Instead of a traditional radio with knobs and dials and everything, a SDR is a computer device – often in the form of a USB stick that connects into your computer, and which is then controlled by a computer program rather than by old-fashioned ‘analog’ controls.

These are amazing gadgets that can be had for as little as $25 (actually, you can get ones for even less than $25, but this specific $25 SDR is the best performing/best value unit until you start going way over $100).  Download the free SDR+ (pronounced ‘SDR Sharp’) software from here, plug the unit into your computer, and run the SDR+ software.  (If you have a Mac, you could try this free software.)

SDR radios have many uses for preppers, particularly as broad-band multi-mode scanners.  We’ll write more about them in future articles.