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Spectra DTMF hold time

Posted: Sun Jan 27, 2008 5:02 pm
by RidgeRunner
I am having a hard time finding how to change the hold time on my spectra. I need to lengthen it up because the DTMF's are not being decoded all of the time. Anyone got any suggestions on this?

Re: Spectra DTMF hold time

Posted: Sun Jan 27, 2008 5:05 pm
by RidgeRunner
I seem to have found it under the conventional programming screen under DTMF options, but I am maxed out out 500ms....I guess I am out of luck...? Anyone?

Re: Spectra DTMF hold time

Posted: Mon Jan 28, 2008 6:13 pm
by Jim202
You haven't supplied enough info for anyone to supply you with a good answer. It
probably isn't the timing on the sending of the DTMF tones. It more than likely is
how your radio and maybe the repeater, if your trying to go through one is adjusted.

Is this radio being used through a repeater?

Are the tones being used through a repeater to be decoded by a receiver listening to
the repeater output?

Have you measured the TX deviation on your transmitter when sending the DTMF tones?

Reason I put these questions to you is that the DTMF tones are very susceptible to
distortion and twist. The DTMF tones need to leave your transmitter at no more than
3 to 3.3 KHz max. This is if your using a 5 KHz max deviated channel. This ensures
that the tones are not into compression when they leave your transmitter.

If your trying to send the DTMF tones through a repeater, the repeater can't be into
audio compression. This too will distort the DTMF tones and they will not decode at
the far end. Most repeaters are set to compress the audio going through them. I
see it all the time, because the radio tech that set up the repeater didn't know how
to adjust this important audio setting.

Jim


RidgeRunner wrote:I am having a hard time finding how to change the hold time on my spectra. I need to lengthen it up because the DTMF's are not being decoded all of the time. Anyone got any suggestions on this?

Re: Spectra DTMF hold time

Posted: Tue Jan 29, 2008 2:06 am
by Will
Number One reason: Excessive deviation, as posted by Jim202 above.
Number Two reason: The compensation alignments are not correct in your Spectra.