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   comp.dcom.telecom      Telecommunications digest. (Moderated)      17,262 messages   

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   Message 16,992 of 17,262   
   Bill Horne to Fred Atkinson   
   Re: [telecom] Little rewards get people    
   30 Mar 23 20:59:04   
   
   prd19.prod.outlook.com> b0f43b01   
   From: malQRMassimilation@gmail.com   
      
   On 3/30/2023 11:27 AM, Fred Atkinson wrote:   
      
   > While I was working as a radio technician for Duke Power Company in   
   > North Carolina] it used to amaze me as to the massive amounts of   
   > misinformation that CB users were spreading around.  Mostly, it was   
   > about radio theory.  I will share three of the many stories I heard.   
   >   
   > We had stopped for lunch at a truck stop one day.  One of my   
   > colleagues found somebody installing a power mike on his mobile CB   
   > unit.  When he asked the fellow why he was doing that, he said that   
   > by putting more audio into the radio, he would get more power out of   
   > it.   
   >   
   > When my colleague explained to him that this was not true, the guy   
   > replied, "Oh, no.  All of the CBers are doing it.  And they are   
   > getting a lot more power out.".  So, my colleague gave up on trying   
   > to explain it to the guy.  He was clearly hopeless.   
      
   Well, it's "sort of" true, at least in theory: the Class=D Citizens   
   Radio Service, which we know as "Citizens Band," uses Amplitude   
   Modulation, just like broadcast AM stations in the 550-1700 KHz   
   Broadcast band.   
      
   In order to perform Amplitude Modulation (AM), the transmitter must   
   add and subtract power from the outgoing carrier signal, and that   
   change is done by the transmitter's modulator, which takes the   
   microphone's signal and amplifies it to change the amount of   
   radio-frequency power going to the antenna.   
      
   However, in most CB sets, the amplified signals from the microphones   
   are run through a low-cost "compression" circuit called a "Clipper,"   
   which is supposed to maximize power output from the radio, but also   
   adds a LOT of distortion, and putting more audio power into the   
   clipper circuit just produces more distortion in the transmitted   
   signal. The increased power from a power mic, sad to say, is usually   
   heard as a distorted and hard-to-understand sound when it's received.   
      
   ... which means, as a practical matter, that "Power" microphones only   
   increase the ability of salesmen to brag about their paychecks at   
   "Power" lunches.   
      
   > We ran into one fellow who had actually installed the truckers'   
   > antennas on a Volkswagen Fastback.  There was absolutely no way this   
   > was going to work as those two antennas have to be spaced wide enough   
   > apart to work properly.  He told me that the truckers antennas   
   > 'prevented messing up your SWR (standing wave ratio) when you have a   
   > 'huge metallic load' behind you'.  Another hopeless radio expert.   
      
   Well, he might not have been aware of it, but that CB'er could have   
   achieved much better results by spending the time to properly bond a   
   single antenna's feedline to the roof of his car, which would provide   
   a proper "Counterpoise," and dramatically increase the "Field Strengh"   
   of the transmitted signal, and also maximize the strength of signals   
   received from other CB sets.   
      
   > There was no point in sharing your expertise with them.  They would   
   > always believe other CB users before they would believe experienced   
   > and well trained FCC-licensed radio technicians.   
      
   [Snip]   
      
   > And there are many other true stories like these.  I just couldn't   
   > believe the massive amounts of misinformation they were spreading.   
   > So many of them appointed themselves radio experts.   
   >   
   > It wasn't long after I worked as a radio technician that I totally   
   > gave up on trying to correct their misinformation.  It was a lost   
   > cause.   
      
   I've commented before on the sad tragedy which is the Citizens Band,   
   so I won't labor the point, other than to say "You're right."   
      
   Bill Horne   
      
   --   
   (Please remove QRM for direct replies)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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