At 10:45 AM 7/8/2005, Mathew Quaife wrote:
>Typically to say, there is nothing in this area as far as repeaters,
>a few on 460 Mhz and one on VHF at 158 Mhz, other than the two cell
>towers more than 5 miles away, that is about it.
This gets into an area that I need to understand better, "how do you
know when it's "good enough"?"
How sensitive does a repeater receiver need to be?
How much isolation do I really need?
How much power should I be running?
All of the above, relative to an antenna, feedline length, mounting
height, and terrain..
Around here, terrain means basically flat, and sites at 100-200' typically.
Radio mobile is good at plotting coverage maps, but then you get into
what's the actual receiver like?
An HT has a pretty lame receiver, lame antenna, and puny transmitter,
but I haven't really looked at those numbers to see if they are all
proportional.
IOW, is the typical HT equally sad on receive, as transmit?
What about a mobile rig?
There's no sense in being an alligator, or a fruit bat, or spending
power and money in cans you don't actually need.
In the can side, I think the answer is, as long as you aren't getting
desense, you've got enough isolation.
You might add cans to get around a particular interference problem,
like a nearby transmitter or receiver that is out of band, but still
causing problems.
At one site, we used to have a 1kW VHF paging transmitter about a
mile away, that put a very nice signal into the receiver, right
through the cans.
But a stub filter took him out easily, since he was pretty far away (152-ish)
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