XPost: rec.aviation.military, soc.history.war.misc, or.politics   
   From: muratlanne@gmail.com   
      
   "a425couple"  wrote in message news:pKUgO.8072$Zr82.4757@fx07.iad...   
      
   >All electronic signals in the Bashi Channel and other areas suddenly   
   >disappeared. Satellite signals, television and telephone signals, etc.,   
   >could not be received without exception.   
      
   The writer couldn't tell whether the signals were jammed, purposely shut off   
   or became stealthy. Commercial receivers are easily jammed but this   
   inexpensive device can show what is or isn't going on:   
   https://makezine.com/article/electronics/getting-started-with-so   
   tware-defined-radio-sdr/   
   The upper panel of the display is a spectrum analyzer, the descending   
   "waterfall" below it Is a record of past activity. A waterfall of FM radio   
   music shows the frequency and duration of each note.   
   "Research and development in the 1990s of software radio, a term later   
   eclipsed by software defined radio (SDR), rapidly spread out of government   
   into commercial efforts,..."   
   That was my job.   
      
   https://en.wikipedia.org/wiki/Spread_spectrum   
   "...but since the signal power is spread over a large bandwidth, the signal   
   PSD is much lower — often significantly lower than the noise PSD — so that   
   the adversary may be unable to determine whether the signal exists at all."   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)