Hi There ACOY, The project I am working on is a cross-band repeater from 5 MHz SSB to 480 MHz FM.
The HF receive circuitry is fairly complex with DSP integrated into the receiver. That is the main reason why I didn't want to prod around inside the radio, especially with pretty limited experience with this kind of thing. 480 MHz transceiver is Phillips version PRM80. This radio already has COR logic on a multi-pin connector on the unit. HF is a Codan NGT-AR. It does not have a logic output associated with the receive squelch. I was hoping to use the line-level audio output to key the PTT on the 480 MHz, allowing me to keep the DSP controlled squelch on the HF (some type of VOX circuit?) Would a high-gain amplifier and a comparator type citcuit let me do this? Have not purchased a repeater controller board yet, having trouble finding one readily available in Australia, at good price. Have seen some good ones in the States, but most are around 3-4 weeks shipping time with postage pretty expensive (any ideas here?) Perhaps I am better to just buy an off the shelve VOX type kit (I have seen a couple of such kits in electronics stores for switching things on and off) than build something from scratch myself? Thanks for your patience. Brendan --- In [email protected], "ac0y8" <[EMAIL PROTECTED]> wrote: > First, I have read the other posts. Exactly what are you trying to > do and what equipment are you using and how are you doing it? If you > are using an FM receiver COR actually is generated by the quieting > of the high frequency noise (squelch noise)when a signal is > received. In other words, when a on frequency carrier comes on > channel the high frequency noise is reduced and the COR changes > state. It's the same general thing as the squelch circuit only the > squelch is ajustable. Hint.... try the squelch circuit for a switch. > I saw a comment refering to AM modulation it prompted the above > questions. > 73 > AC0Y > > > --- In [email protected], "bsoutheyoz" > <[EMAIL PROTECTED]> wrote: > > I am having trouble generating a COR / COS signal for my new cross- > > band repeater project. I do not want to pull my expensive > > transceiver apart to try and locate an internal COR circuit. > > > > I have seen several commercial circuits that generate a COR > singnal > > based on logic that detects a drop in RF noise when a carrier is > > detected (receiver squelch always open) but this will obviously > only > > function properly on FM. > > > > Most repeater controllers seem to require a 3 V or better input > > signal change to key COR. I guess even high-level speaker audio > out > > will not be sufficient to generate this voltage (??), so my > question > > is : > > > > does anybody know of a cheap repeater controller that will > generate a > > COR signal with audio in only? > > > > Thanks in advance, > > > > Brendan Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
