[ARC5] Zero Beat Question

[Glen Zook]

If you watch the "S" meter, as it gets closer, and closer, to zero beat the needle will start to vibrate and the closer to true zero beat the slower it will vibrate.  When the needle moves, from side to side, taking more than a second, you are within 1 Hz of true zero beat.

 Glen, K9STH 
Website: http://k9sth.net

      From: D C _Mac_ Macdonald <k2gkk at hotmail.com>
 To: "WB6KBL Knoppow, Richard" <1oldlens1 at ix.netcom.com>; ARC-5 Mail List <arc5 at mailman.qth.net> 
 Sent: Monday, July 11, 2016 12:45 PM
 Subject: Re: [ARC5] Zero Beat Question
   
<!--#yiv8592925088 .yiv8592925088hmmessage P{margin:0px;padding:0px;}#yiv8592925088 body.yiv8592925088hmmessage{font-size:12pt;font-family:Calibri;}-->Attempting to "true" zero beat with a modern receiver 
or transmitter can be frustrating, for sure. 
 
This new gear has either crystal or digital filtering which 
effectively removes low pitched "sounds" below around 200 or so Hz.  
 
However, a receiver/transceiver with passband tuning is 
capable of restoring sound down to below 60 Hz.  The audio 
circuits in communications gear probably won't go much 
below 25 Hz, though. 
 
As others have noted, as two signals get closer and closer 
to equal, you can hear an increasingly slower wah-wah-wah 
sound. The slower that sound gets, the closer you are to 
true zero beat. 
 
You can frequently hear this at night on an AM broadcast 
radio when two fairly weak distant stations are within just 
a very few Hz of each other. 
 
It's a phenomenon with which we old farts and the primitive 
gear which we used "way back then" are more familiar! 
 
As some others have noted, using skill and stable VFOs, we 
could frequently work the SSB folks (using full carrier AM) 
and not be discovered until an SSBer tuned off frequency 
for some reason or another!  'Twas great fun for sure! 
  
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