External squelch control for Motorola radios
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External squelch control for Motorola radios
Does anybody have any information on an external squelch control for Motorola M1225, CDM750 models? I used to be able to do this with Vertex way back when they stopped using external squelch. Does anybody know why external squelch pots are not used?
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- was grem467
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- Tom in D.C.
- Posts: 3859
- Joined: Tue Sep 04, 2001 4:00 pm
- What radios do you own?: Progreso soup can with CRT
External squelch control...
I own an old MT500 which was once owned and used by an airline and it's an omni with no external squelch, though the pot can be found and adjusted inside the radio.
Absolutely no reason for doing this except to keep the help from messing with the squelch setting, IMHO.
Absolutely no reason for doing this except to keep the help from messing with the squelch setting, IMHO.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
The function of the squelch in a VHF or UHF radio is to kill mostly its own internally generated noise when no RX signal is present. This is the noise you hear when no antenna is connected and the squelch is open. In older radios this noise was less constant because of temperature and voltage variations in both the RF circuits and the squelch circuit itself. The front panel squelch control allowed compensating for these variations.
Modern radios are far less sensitive to these variations and consequently do not need an external squelch control any longer. Models like the CDM, M1225, P1225 and the Warris series do have an optional setting in the RSS that allows a button to be programmed for tight or loose squelch if needed to eliminate light interference when only carrier squelch without PL is used.
Nand.
Modern radios are far less sensitive to these variations and consequently do not need an external squelch control any longer. Models like the CDM, M1225, P1225 and the Warris series do have an optional setting in the RSS that allows a button to be programmed for tight or loose squelch if needed to eliminate light interference when only carrier squelch without PL is used.
Nand.