Threaded... > John Barrett wrote: > > A repeater is NOT full duplex.. it is not simultaneously processing > completely separate audio streams in and out.. it is processing the > SAME audio in and out.
So because the content in both 'directions' (TX and RX) are the same, that disqualifies it as 'full duplex'? > There is only ONE audio path full duplex requires TWO. There are two - the incoming and the outgoing. If you want to get technical, they are often not the same due to delays in audio processing. > Telephones accomplish this by modulating both audio > signals on a common carrier (the DC power provided by the telco), > modems do it by using different tone frequencies for send and > receive.. essentially half duplex, but coerced into being full duplex > by the behavior of the telephone line. The modems accomplish this by > negotiating which modem will use which frequencies (hence all the V## > protocols.. they define how the modems negotiate) We are talking radio here, not telephones. The telephone industry may have different definitions of the same terms. > A repeater is NOT bidirectional audio streams flow in only one > direction, from sender to reciever I never said it was bidirectional. You could make it bi-directional, but not both directions at the same time. > From this point of view the repeater is a filter in a half duplex > link. The only reason a repeater uses 2 frequencies is because you > cannot transmit on the same frequency as you receive.. Read what I said before. In a half duplex setup, you CANNOT receive and transmit at the same time. This clearly does not exist in a repeater (except a simplex repeater). Pa State Police use a Half Duplex system. They transmit on frequency X and receive on frequency Y. Neither is repeated on the other. The users of a repeater are most often operating in a Half Duplex mode. They cannot TX and RX at the same time. Again, radio terms may not perfectly follow telephone or computer terms. A repeater in computer-land is something quite different than in radio-land. In radio, a scanner is a device that scans radio frequencies. In computer-land, it's a device that converts printed matter into electronic form. Not everyone's terms will always match. The definitions I gave (quoted below) are for radio-land only. Sometimes, even in radio-land terms do not match. What hams call an Autopatch the Land Mobile industry calls an Interconnect. It's the exact same thing, but with different terms. Likewise, sometimes the same term is used to describe two different things. BUT, even in comptuer-land, a full duplex ethernet card is a device that can RX and TX at the same time - just like in radio-land. Half Duplex cards can both TX or RX, but not at the same time. (just like the definitions I gave) Joe M. > ---------------------------------------------------------------------- > > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of MCH > Sent: Thursday, November 08, 2007 10:28 PM > To: [email protected] > Subject: Re: [Repeater-Builder] Part 97 question reference to Repeater > control > > > > Simplex: One frequency - you can either TX or RX, but not both. > > Half Duplex - Two frequencies - you can either TX or RX, but not both. > Your TX frequency is different than your RX frequency. > > Full Duplex - Two frequencies - you can RX and TX at the same time. > > A repeater is Full Duplex operation. It can RX and TX at the same > time. > > Bi Directional means you can come in on one frequency and go out the > second, or come IN the second and go OUT the first. > > Joe M. > > Nate Duehr wrote: > > > > On Nov 8, 2007, at 2:34 PM, Paul Plack wrote: > > > > > Manufacturers sometimes market features on new radios without > regard > > > to Part 97. I have an Alinco DR570T, one of the first, if not THE > > > first, dual-band mobile to feature full duplex crossband repeat. > As > > > designed, it's crossband repeat function was clearly not legal. > > > > From your description (and knowing the radio) you mean "bi- > > directional" (but not at the same time), not "full-duplex" (which > > means you can go both directions through it at the same time). > > > > I'm seeing the term "full-duplex" misused more and more in regards > to > > dual-banders in cross-band repeat mode... did someone publish an > > article with this less-than-accurate terminology again somewhere? > :-) > > > > -- > > Nate Duehr, WY0X > > [EMAIL PROTECTED] > > > > > > Yahoo! Groups Links > > > > > > > >
