In article ,
Jeff Liebermann wrote:
Good plan but there are problems. Most hams these daze use walkie
talkies with perhaps 1 watt of TX RF. The typical repeater is running
perhaps 10 to 40 watts out (after the duplexer). The walkie can hear
the repeater almost anywhere, but when trying to talk, they drop in
and out all the time. The mobiles, which run more power, are usually
well matched to the repeater's tx power. I've suggested adaptive tx
power control (to preserve battery power) on our 2 meter repeater, but
nobody wants it.
Seems to me that would introduce another set of incompatibilities.
People out on the fringe area of the repeater's coverage would be able
to hear repeated signals from weak transmitters (e.g. HTs), but if the
repeater saw a strong input signal from a mobile (or an HT near the
site) and dropped its transmitter power, the repeater coverage area
would shrink abruptly and those users out around the edges could lose
coverage. This could re-create the "hidden node" problem in a new way!
I don't think adaptive power management can work reliably in the
absense of a signal-quality feedback from each station which is
accessing the repeater/AP.
We had a co-channel user that was running carrier squelch. It took
only about 7 years of constantly pounding on the trustees before they
would install PL. They lied on their NARCC application claiming they
had a functional PL system.
Grrr. Worf "Romulans have *no* sense of honor." /Worf
Our system (W6ASH, SPECS, at El Camino Hospital in Mountain View)
switched over to PL-tone-only years ago, and it helps in numerous
ways... the absence of noise-initiated kerchunking is a real blessing.
I've preserved the ability to switch the repeaters over to
carrier-sense-only in an emergency but really don't expect to ever
need to use this feature.
The experience taught me a few things,
one of which is that hams generally make lousy RF neighbors.
Some are lousy neighbors, lazy and self-centered. Others hold
themselves and their equipment and operation to very high standards. I
think it depends very much on the individuals involved, on their
attitudes, and on their level of prior experience in supporting a
real-world user community.
No, it's not for most home systems. There's a similar coexistence
problem with mesh networks and municipal networks. Neither of these
scale very well. They work ok with a small number of repeaters, but
rapidly foul up as the usage, traffic, and number of repeaters
increases to the point of mutual interference. Details and a rant on
request.
I believe you!
My impression is that a limited set of mesh repeaters, and a plentiful
set of direct backhaul links on a different (non-interfering) band,
works out rather better.
--
Dave Platt AE6EO
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