[ICOM] Tone squelch operation, "uniformed" question - REPLY

[r morris]

     Back in the olden days, before cell phones, and before Icom and Kenwood, Motorola, GE and RCA made lots of money selling two way radios in the commercial world. The "community repeater". A single freq repeater with an auto multi PL select. The game also worked on a simplex freq. Sell a base station to Joe the plumber, Fred's TV repair, Jack the heating guy, put a mobile in his truck and mic and telephone in front of the wife. Since there are only so many channels, put a bunch all on the same freq with different PL. What's PL, Private Line, a sales and technical gimmick, fixing it so Joe does not have to listen to Fred.

     The FCC rule, in the commercial world, was you had to "monitor" the freq before making a call. Most of microphones had a metal hangup thingy on the back and the "hook" on the dash was grounded. When you picked up the mic it went off ground and switched off Rx PL, hence "monitoring" the channel. Most radios had a "monitor" button on the front. My Kenwood TH6 HT has one one the side.
      An easy way to do it with today's radios, is put the same frequency in more than one memory with one, no PL, one for your buddies, one for your wife. Switch to M1 (no PL), make the polite call, is anyone using the freq, switch to M2, or M3 to open who ever's Rx.
       How do you think ham FM and repeaters got started. All the old junk that got traded in when Joe got sucked into new radios or the local police traded up. Don't ask how I know this.....

P.S. PL was copyrighted by Motorola and developed it, the rest of the world had to call it CTCSS, continuous tone coded squelch.



    




>________________________________
> From: Mike Olbrisch <mike-2007 at elp.rr.com>
>To: 'ICOM Reflector' <icom at mailman.qth.net> 
>Sent: Tuesday, February 14, 2012 10:59 AM
>Subject: Re: [ICOM] Tone squelch operation, "uniformed" question - REPLY
> 
>The only real problem would be that the two stations monitoring using tone
>would never hear if the frequency is in use by non-tone stations.  Unless
>they physically look at the meter, they might transmit into a frequency
>already in use.
>
>The fix to this is easy.  Tell them to use 146.520 simplex.  I have traveled
>thousands of miles to and from dog shows.  I have made a lot of calls in
>dozens of cities on 146.520, and never gotten a reply.  That is a pretty
>clear frequency.
>
>Interestingly enough, in my travels I have had better luck on 144.200 USB
>than I have had on 146.520 FM.
>
>Vy73 - Mike - KD9KC.
>El Paso, Texas - DM61rt.
>W5-SOTA Association Manager.
>W5-SOTA info: www.qsl.net/kd9kc/
>
>
>
>
>-----Original Message-----
>From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
>Behalf Of George J. Nixon Jr.
>Sent: Tuesday, February 14, 2012 08:45
>To: ICOM Reflector
>Subject: [ICOM] Tone squelch operation, "uniformed" question - REPLY
>
>Thanks to all who responded.  The reason for the question is that my
>daughter and her husband (both relatively newly licensed amateur radio
>operators) are getting involved in a local emergency response program in
>their area, heard discussion of using the tone squelch feature from another
>local ham and didn't understand it.  I explained setting the
>transmit/receive tones, but had this question to throw into information for
>them. 73 - George, N9EJS = = = = = = = = 
>
>----
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