Bob,
This is an easy one! Since we are now dealing only with receivers, the
issue is merely how to feed two receivers their respective signals
without any degradation from the original condition. This calls for a
classic application of a receiver multicoupler. Ideally, the input
signal is fed through a bandpass filter that allows only the desired
frequencies to pass. A low-noise amplifier boosts the signal level and
delivers it to a splitter which provides a 50 ohm match to each
connected receiver while isolating them from each other. The key goal
is to have the same, or a little higher, signal level to the original
receiver as it had before the addition. Please don't be tempted to use
a simple tee connector to split the signals. While this may work just
fine, there are gremlins poised to complicate your life with mismatches,
intermodulation, and other nasty things, so don't cheap out at this
point! Trust me, any action that "lowers the bar" now will return, big
time, to haunt you in the future. Use double-shielded coax everywhere,
and avoid the use of barrel connectors or adaptors. This is not a big
task, but you must insist on the application of good engineering
practices.
Don't forget to use low power and circulators, if necessary, to ensure
that your UHF link radios don't interfere with each other.
73, Eric Lemmon WB6FLY
[EMAIL PROTECTED] wrote:
>
> Hi, all --
>
> I am on the technical committee of an amateur repeater club. A club in the
> next county has approached us to ask about sharing one of our 2m receive
> sites with them. It's a commercial site and we are there at the pleasure of
> the owner, who is willing to accommodate them and thinks that there are no
> bad mixes.
>
> The other club has asked to share our 2m receive antenna and feedline, and
> has volunteered to install whatever equipment we specify so that our site's
> performance is not degraded.
>
> While this sounds doable to me, I am more of a digital guy than an RF guy.
> What should we install in order to do this "the right way" without degrading
> our site's performance?
>
> Our system transmits on 146.88 MHz and receives on 146.28.
> We use a Motorola receiver (I think it's a Micor).
> The other club's system transmits on 147.345 and receives on 147.945.
> Both have links in the 440 band.
> Neither system will transmit on 2m from this site.
>
> Any advice or recommendations as to architecture, equipment that works (or
> doesn't work!), or points to be included in a Memorandum of Understanding,
> would be appreciated.
>
> Regards,
> Bob Koblish
>
> [EMAIL PROTECTED]
>
>
> Yahoo! Groups Links
>
>
>
>
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