Portable/back up transceiver

"RST Engineering - JIm" wrote in message
m...

"Mike" nospam @ aol.com wrote in message
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"RST Engineering - JIm" wrote in message
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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?

Sure, you can transmitt 55 watts. Provided you can find a FCC approved
device to do so. Good luck with that. Do you ever wonder why Vertex, Icom,
Sporty's, and other handhelds all list their specs as 5w PEP, 1.5w carrier?
Do you think they provide such limited power just for sh**s and giggles?



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?

You can skip the bullcrap, Jimmy. All handheld airband transceivers on the
market today have essentially identical antennas which are close enough to
omnidirectional for this discussion even if it isn't for mental
masturbators like yourself. So you can continue to **** on everyone's shoes
and try to tell them it's raining if you like, but I've already told you
your mental wanking exercise is about as useless to this discussion as man
nipples.




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.

No, I have a very good idea what I'm talking about Jimmy, which is very
unfortunate for you since you can't pull your usual trick of trying to
baffle everyone with bullcrap. Vertex, Icom, Sporty's and a few other
lesser known brands all put out 5w PEP/1.5w carrier according to their specs
and all of them have virtually identical antenna designs. The FAA radios
put out about 7-9w carrier at the antenna which is pretty close to 7db more
power. The FAA receivers are undoubtedly more sensitive than the handheld
receivers, but not by 7db, and their squelch is set to around 5 microvolts
anyway which is probably going to be pretty close to the handheld. So
obviously the most significant range limiting factor is the handheld's
transmitter. So you can spew all the crap you want about how I have "no
idea", but you haven't offered one iota of anything that is even remotely
useful to this discussion and all you're really concerned about is trying to
impress yourself with what you think you know. It's the same old grind with
you, Jimmy. Nobody on RAP can offer any info on radios because they have
"no idea" and you're the only one who does. Then when you're done blowing
smoke up everyone's drawers you failed to provide any information that's
even remotely useful to the discussion.





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?

I'm pretty sure it's not with a ICOM A14, a Sporty's SP-200, or anything
remotely resembling one. So again this begs the question, Jimmy, what value
does your mental masturbation exercise bring to the subject line of your
post?




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.

So you managed to impress yourself. Good for you, Jimmy. That's all you're
really good for, but I must give you credit. At least you're honest about
it.