Adam, A good question.
The reason it will not generally work is that analog voice repeaters have a variety of filters and audio amplifiers that are designed to emphasize the human voice. These same filters and audio amplifiers distort the GMSK signal of D-STAR to an extent that it cannot be decoded on the repeater output. A repeater can be designed to pass the signal through "flat", that is no modification of the audio, and it may pass GMSK just fine at that point (it may take a lot of tweaking and/or an inversion in the signal) as well as analog voice. This is usually accomplished by tapping the repeater's receiver discriminator and routing it directly to the repeater's transmitter modulator. And, yes, it would be very irritating to the analog FM users, and if they didn't know what was going on, they may key right over the D-STAR signal, disrupting the DV conversation. Adam Karsin wrote: > > > Ok with all the talk of interfacing DV and FM, here is another > question.... > if there is an FM repeater, that has no tone whatsoever, what is it about > Dstar that it wont pass through? > I know all the obvious like it ticking off all the FM repeater users, > and so > on... but lets say that I have a 2M FM repeater (I don't but work with me) > on 147.000 + CSQ. I know that if I set me radio to that frequency and > offset > in FM it works. Simple enough, we have used these for years. Now, my buddy > and I on our HT's very simply toggle into DV mode, why would this not work > the same? I know anyone not using dstar would only hear static, but > that for > the purpose of this question is not important. (lets call it a private > mobile repeater) so there is no one else on. > > Just a question, don't drag me before the firing squad!! > > Adam > KG4WWH > > _ -- John D. Hays Amateur Radio Station K7VE <http://k7ve.org> PO Box 1223 Edmonds, WA 98020-1223 VOIP/SIP: [email protected] <sip:[email protected]> Email: [email protected] <mailto:[email protected]> [Non-text portions of this message have been removed]
