I was referring to using the circulator in place of the T connector in a duplexer that was being discussed in earlier threads.
An isolator is a circulator with a load on one of the ports. Again, the circulator will produce intermod when external strong signals enter the antenna port when used as a switch for the duplexer and there is transmitter power also going through it. 50 Watts or 47dBm to -116dBm receiver sensitivity is 163dBm dynamic range. The device is not linear enough to prevent detectable IM when strong signals are received that are of the correct frequencies to cause IM to a receiver. your 3rd item deals with the circulator in an isolator configuration and prevents those strong signals from getting to the amplifier which is much more non-linear than the circulator. But if you were to feed two RF transmitters through one isolator (assumed through combining filters), there would be significant levels of IM produced. Please investigate for yourself the characteristics of third order intercept points and amplifiers to see the effect of signal levels on non-linear devices. Passive IM from ferromagnetic materials are similar. There are people on here that know more in certain subjects than thou. Harold Farrenkopf, P. Eng. --- In [email protected], Ken Arck <[EMAIL PROTECTED]> wrote: > > At 09:51 AM 10/24/2007, you wrote: > > >OK, I have to comment, > > > >An isolator/circulator should not be used in a duplexer at the > >antenna connector when there are other strong signals floating > >around the air that can get into the isolator. > > <---Uhhhhh...a couple of things here: > > 1) Did I miss something here? Did someone suggest connecting a > circulator to the antenna port of a duplexer? > > 2) The whole point of a circulator is to act as a "one-way" path for > RF. Placing it in the antenna path is a bit counterproductive, no? > > 3) I disagree with your comments about "strong signals that can 'get > into' the circulator. Again, that's the whole point, isn't it? > > Ken > > ------------------------------------------------------------------------------ > President and CTO - Arcom Communications > Makers of repeater controllers and accessories. > http://www.arcomcontrollers.com/ > Authorized Dealers for Kenwood and Telewave and > we offer complete repeater packages! > AH6LE/R - IRLP Node 3000 > http://www.irlp.net > "We don't just make 'em. We use 'em!" >
