Motorola Talkabout "QT Noise Filter"
Rick
"QT Noise Filter", also called "Quiet Talk Noise Filter". The User's
Guide only has this to say about it: "QT Noise Filter filters out
unwanted transmissions in heavy radio traffic areas." That's it. No
usage instructions or technical details. In the menu choices, it can
be turned on or off.
By experimenting with the radios and an HP 8920A RF Test Set, I found
out what this feature is and how to use it. These radios, upon
pushing the "call" key (the key with a music note on it), transmit a
55 Hz tone with 500 Hz deviation for 500 ms, followed by whatever
"Interference Eliminator Code" is set: 0 = no sub-audible tone; 1-38 =
standard 67.0 to 250.3 Hz sub-audible tones; 39-99 = Digital Coded
Squelch (DCS) 23-bit patterns. When the receiver radio has QT Noise
Filter turned on, it requires the 500 ms of 55 Hz to de-squelch, in
addition to its configured Interference Eliminator Code. Also, once
de-squelched in this way, the receiver will de-squelch for signals
that do not have the 55 Hz tone, until 30 seconds of non-use have
passed.
Rick
WA6NDR (amateur)
WQEV703 (GMRS)
Rick Nungester
The feature is sited elsewhere as meaning "Quick-Talk Noise Filter.
mryan
I've had some problems with tone squelch flasing in high traffic areas as
well. I've cured it for the moment by just using DCS. Apparently it isnt as
easy to false.
"Rick" <nung...@mail.com> wrote in message
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