Eric, One other comment. Since connecting the receivers in parallel one must make sure one is using squelched audio. If open squelch audio, the noise will probably interfer with the other receiver audio.
In most applications of 2 TNCs to one rig all except the TNCs TX audios are just hardwired lines, no components except connectors. Again the TXs need to be isolated with resistors. 73, ron, n9ee/r >From: Ron Wright <[EMAIL PROTECTED]> >Date: 2007/08/02 Thu AM 07:45:59 CDT >To: Repeater-Builder@yahoogroups.com >Subject: Re: RE: [Repeater-Builder] Connecting Multiple TNCs > >Eric, > >I am sure you can connect the audios together from/to both rigs. One would >have to isolate the TNCs TX audio using just a couple of resistors. Their >values would depend on the rig TX audio input impedance, but typically is high >on Ham rigs so 1 kOhms resistors would probably work. > >The PTTs from each probably can be parralleled also allowing either TNC to key >the rig. Most times the TNC's PTT is open collector or relay that simply >pulls to ground to key. It would act as two switches in parrallel. > >I don't think you need a COS to indicate receive. Most TNCs simply >continously sample the received signal and respond when in the correct format. > When it sees, for instance, a valid packet burst it decodes and responds. > >73, ron, n9ee/r > >> >>Eric Lemmon <[EMAIL PROTECTED]> wrote: Dave, >> >>I'd like to see that article, too. Connecting two TNCs to one radio is >>easy, but allocating the RX and TX functions between two devices is hardly a >>trivial matter. Unless a buffer is used to store outbound data while the >>radio is busy receiving data on the other TNC, collisions will occur >>regularly. This should be interesting! Is this a good idea? >> >>73, Eric Lemmon WB6FLY >> >>-----Original Message----- >>From: Repeater-Builder@yahoogroups.com >>[mailto:[EMAIL PROTECTED] On Behalf Of >>[EMAIL PROTECTED] >>Sent: Wednesday, August 01, 2007 4:51 PM >>To: repeater-builder@yahoogroups.com >>Subject: [Repeater-Builder] Connecting Multiple TNCs >> >>Hi all >> >>Some time ago, I saw an article on how to connect two TNCs to a single >>radio. Does anyone remember such an article an either have a copy or point >>me to a site where I can download it? >> >>Thanks, >> >>Dave, WA6IFI >> >> >> >> Pinpoint customers who are looking for what you sell. > >Ron Wright, N9EE >727-376-6575 >MICRO COMPUTER CONCEPTS >Owner 146.64 repeater Tampa Bay, FL >No tone, all are welcome. > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
