Kevin Custer wrote:
> If we went around putting 3 dB pads on our repeaters until someone
> noticed, we'd soon have a repeater that no one would be able to use. In
> this forum, most of us strive for the best operation we can afford, or
> set-up up to our best ability. A matched system is one that works as
> well in one direction as it does the other. With the results of Jeff's
> testing, which match closely my own, the numbers speak for themselves.
> A repeater receiver with -125+ dB of sensitivity needs 150+ watts to
> remain a matched system.
This has been a bit of an interesting thread. It's interesting to see
how things differ for different areas, users, and owners.
My UHF Micor rptr has a Hamtronics GaasFet, which I have had good luck
with, only complaint ia that it MUST be mounted on a metal plate, as the
bottom is open. Otherwise it seems to work as well as an ARR. Anyway, I
measured an *actual* sensitivity at the connector on top of the cabinet,
after the T1504 duplexer, of -121dBm. At the same point, I showed about
35W out. I consider it a very balanced system, but that's a relative term.
Since most UHF users are on handhelds, that's the point of reference.
And I find that with a 2W h/h, as long you can hear it well, you will
likely be adequate copy. But it can be heard like that just about
anywhere most of the users are.
With a 35W mobile and a 1/4-wave on the roof, I find if you can copy it
at all, you will likely be near 100% copy into it.
So calling a system 'balanced' is a matter of what you're user base is,
mobiles or portables, and even what a typical unit in each type is.
Around here, a 'typical' mobile on 2M is still 25W with a 1/4-wave. On
UHF, it's 10-15W with a 1/4-wave. Portables on 2M are typically 4-5W,
and UHF is typically 2-3W.
--
Jim Barbour
WD8CHL
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