Yes, look for a combiner for the commercial repeater industry in
addition to the duplexers.  Expensive items.   


###
BRETT WINCHESTER  KD7JN 
[log in to unmask] 
208-639-8386
###


-----Original Message-----
From: For blind ham radio operators
[mailto:[log in to unmask]] On Behalf Of Colin McDonald
Sent: Wednesday, December 19, 2007 4:54 PM
To: [log in to unmask]
Subject: multiple radios, one antenna

here is a question for the list:
I want to have my main VHF/UHF transceiver hooked up to my single dual
bander, while at the same time using that same dual band antenna for
another transceiver and a scanner at the same time.
I don't want to have to manually switch the antenna over to the
different radios via an antenna switch.
What i need is some sort of distribution device that will allow me to
transmit on either of the VHF and or UHF radios, without damaging either
the other transceiver or the scanner.  And then when there is no rf
being transmitted, to be able to have all 3 receive properly using the
one antenna.
My question is, is there such a device availible?
I know about distribution amplifiers for receive, but i don't know if
you can transmit through those, and i also need something that will
prohibit any rf getting back into the other radios.
I know that any receiver that is on the same band will be desensatized
as soon as I transmit, but i am not concerned about that since if i were
using a separate antenna, that would occur in the near field anyway.
I require such a device because i can only really have one good dual
band antenna at any height and i have several different rigs i want to
be able to use to monitor and transmit on, as well as listen on the
scanner.
I know that in multi-frequency systems, such as a public safety
organization, or even public transit, they often have multiple radios on
the same band going at the same time for dispatch or communications
purposes, all using the same antenna....i suspect they use some sort of
tuned cavities to prevent desensatization...
I need a little box that i can plug my antenna into, and plug 3 radios
into the other side and not worry about my 50 watts of rf on VHF getting
back into the antenna jack of the other radios and blowing out the front
ends.
any help is appreciated in finding a solution to my wishes.

73
Colin, V A6BKX