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[aprssig] Mic-E and HTs

VE7GDH ve7gdh at rac.ca
Tue Dec 13 16:52:51 UTC 2005


Bob WB4APR wrote on Dec 13 2005

> Also, I notice in the TT3 schematic that the 2.2k
> resistor that mixes the audio and PTT for
> combined handhelds seems to be in the wrong
> place. It should be in series with the Q1
> output so that the Q1 does not load down
> the audio. As shown, the audio is essentially
> shorted by the PTT transistor when it keys.

I don't think so. PTT OUT goes to pin 3 of J1 for radios with dedicated PTT.
Note that where it says AUDIO OUT after C1, it is connected to AUDIO OUT on
pin 1 of J1. On most HTs (non-Kenwood), the PTT is essentially via R8. When
used with a mobile or Kenwood HT, R8 shouldn't be installed.

Did I get that right? <g> Not enough sleep for the last week.

73 es cul - Keith VE7GDH
--
"I may be lost, but I know exactly where I am!"





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