that is what i was thinking too.
Except a duplexer seems to allow for use of two transmitters and receivers
within the same band, but not the same band pass...in other words the
filters have to be set up so that each transceiver can only talk or listen
on a certain band width. without the two ever crossing.
So for instance, i could have one transceiver on 144 to 146MHZ, and another
transceiver on 146 to 148 MHZ, but neither radio could just go where ever it
wanted between 144 and 148 without having to reselect the band pass for that
radio.
I guess what i am looking for mostly, is something that will trip a switch
on all the ports as soon as i start transmitting on one radio.
This will keep the rf from going directly into the other radios while i
transmit.
And, something that has a proper distribution amplifier built in so there is
no signal loss with multiple receivers going off one antenna...
I basically need a multicuppler for the receive side, but one that can
except rf going back through it from the transmitter, and that will
instantly shut down all receiving ports while that rf is going back through.
A multicuppler usually will receive from say 50MHZ to 2GHZ, so the receive
is certainly wide enough.
A duplexer has fairly narrow filtering only a few megs wide usually.
anyway, i'm still searching for what i want.
73
Colin, v a6BKX
----- Original Message -----
From: "Steve" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, December 20, 2007 8:08 AM
Subject: Re: multiple radios, one antenna
> A duplexer?
>
> ----- Original Message -----
> From: "Colin McDonald" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, December 19, 2007 6:53 PM
> 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
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.503 / Virus Database: 269.17.5/1190 - Release Date:
12/19/2007 7:37 PM
>
>
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