Portable/back up transceiver

"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)

47CFR87.131 gives the maximum power permitted in the VHF com band as 55
watts carrier. WHere do you get your misinformation?

and since all of them come with essentially identical
omnidirectional antennas,

An omnidirectional (isotropic) antenna is an impossibility, although we do
some mathematical "tricks" to reference all antenna gain to isotropic. Gain
(dbi - decibels above or below isotropic or dbd - decibels above or below a
dipole) by definition are 2.14 dB different, the dipole having gain
perpendicular to the elements of 2.14 dbi. Tell me what the form factor is
for an antenna putting out a radiation pattern resembling a grapefruit?


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.

Either you have no idea what you are talking about or it is well into
beer-thirty for you.



So you can use the opportunity to mentally masturbate your "engineering"
knowledge and talk about theoretical true parabolic reflectors

Who said anything about parabolic reflectors? I used a plain old ground
plane at both ends. 2.14 dbi gain.

End one. One watt AM carrier power into a ground plane. End two receiver
with one microvolt sensitivity for 10 dB S+N/N being fed by an identical
ground plane. If you like, you can replace the ground plane antennas with a
plain old straignt dipole with no measurable gain or loss. Actual range at
127 MHz. is 1366.7 statute miles.

How the hell do you think we talk to the space shuttle with essentially the
same equipment a few MHz. higher with 1 watt handhelds?


and receiver
sensitivities that don't even approach practical applications

Every transceiver on the market today will give you at least half a
microvolt for 10 dB S+N/N. I was being generous by saying a full microvolt,
which will give you a much better s/n ratio. Haven't designed many VHF
radios, have you sonny?


, but you're
not really contributing much to the OP's question.

Perhaps. Perhaps not. But at least I knew what the hell I was talking
about.

Jim