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Old August 3rd 09, 01:02 PM posted to rec.aviation.piloting
Mike
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Posts: 573
Default Portable/back up transceiver

"Peter Dohm" wrote in message
...
"Mike" nospam @ aol.com wrote in message
...
"RST Engineering - JIm" wrote in message
...
Given the fact that a 1 watt transmitter on one end and a 1 microvolt
receiver on the other end have a maximum theoretical range of 1800
miles, how in the world can you say that a 4 watt transmitter is
"limited by power output"?

The limitation is always by line of sight or antenna configuration.


Since all transceivers of this type are limited by the FCC in regards to
how much power they can output(and most of them develop the max power
allowed at about 1.5w nominal) and since all of them come with
essentially identical omnidirectional antennas, I can pretty much assume
they will all have very similar ranges, since obviously the transmitter
is going to be the limiting factor seeing as how the other end is putting
out roughly 7db more power.

So you can use the opportunity to mentally masturbate your "engineering"
knowledge and talk about theoretical true parabolic reflectors and
receiver sensitivities that don't even approach practical applications,
but you're not really contributing much to the OP's question.


I don't always agree with Jim; but he is absolutely right on this one.

When I worked as an avionics technicial, most of the problems that I saw
were ultimately wiring issues of the coaxial cables (frequently broken at
the antenna connector) and only occasionally degraded sensitivity of the
receiver. That was long ago, and more modern receivers should suffer far
less degradation.

The most entertaining case was a Bellanca on which one of the two comm
transceivers would successfully receive the tower frequency about 6 miles
from the airport and transmit just a little further. It turned out that
there was an in-line coax connector which had become disconnected and the
radio signals both transmitted and received were only through the braiding
of the coax cable!

Peter


The subjet is "Portable/back up transceiver"