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Old August 3rd 09, 05:47 PM posted to rec.aviation.piloting
Ross
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Posts: 463
Default Portable/back up transceiver

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

Sure, you can transmitt 55 watts. Provided you can find a FCC approved
device to do so. Good luck with that.


Collins, Sperry, RCA and a few other designed for airline service have a
minimum output of 30 watts, achievable last time I looked by either an 829B
or a pair of 6146s. That was when I was with the airlines many moons ago.
I'm sure that they have improved their designs in 45 years, but I am not
sure that even they will go away from devices that can put up with
horrendous VSWRs and just get a little hotter. Put your money where your
mouth is, bozo, and go buy this sort of gear if you want in the neighborhood
of 55 watts.


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?


Of course not, **** for brains. There are two limitations for handhelds.
One is the amount of power you can get from internal batteries, no matter
how good the technology. The other is designing to price point and not
being able to afford multiwatt solid state devices. Toshiba has a couple of
really nice 7 watt ones, but they run about $20 a stick which adds $60-80 to
the list price of the radio. That is a marketing disadvantage that they are
not willing to take

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.


If you are talking about the rubber resistor that comes with most handhelds,
then you apparently don't understand the problem OR the OP does not
understand that rubber duckies are fine for about 5 to 10 miles and then
are, as you say, breasts on a bull.

We did some tests with our S&R unit using three antennas ... the rubber
duckie, a home-made collapsible quarter wave whip with a coax connector
soldered to it to fit the radio, and an external ground plane antenna fed
with ten feet of coax. If you take the ground plane as the standard, the
whip was -5 dB and the duckie was -15 dB.


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.


Engineering calculations can be bullcrap and it is up to the student to
prove otherwise. So far all I've heard is dynamic circumlocution and
periphrastic pleonasms.


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.


As do Microair, XCOM, the older Genaves, Baysides, Dittel, and a few other
radios designed to be permanently mounted in an aircraft.


The FAA radios
put out about 7-9w carrier at the antenna which is pretty close to 7db
more power.


What the hell is an FAA radio? You do realize that the FAA does NOT have
any avenues for approval of radios other than the original equipment list
that came with the airplane? I've got a '58 Cessna; the only "approved"
radio for that genre of aircraft was the venerable old (vacuum tube)
Mark-12. No King, no later Narco, no Genave, no Icom radio was ever
"approved" for those aircraft, yet the "wink and nod" method of installation
has been used universally for installation of virtually any com radio
manufactured. The FAA has taken the tack that if it OK with the FCC, it is
OK with them. Which is just fine with all the rest of us.




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.


Anybody that designs a VHF receiver for anything less than a microvolt is
just asking for trouble, but I don't buy 5 microvolts. Even if I did, a 1
watt transmitter produces 5 microvolts with ground planes (or quarter wave
whips, or dipoles) at 300 miles, so we are back to the original argument.
Transmitter power has damned little to do with it.


So
obviously the most significant range limiting factor is the handheld's
transmitter.


That, sir, is patent bull****. Go work the range equation with a noise
bandwidth of 25 kHz. and see what YOU come up with. Post it here and we'll
argue numbers. Until then you are just blowing smoke up your undies.


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.


I'm not trying to impress anybody; I'm trying to show facts and figures. So
far all I've heard from you is rhetoric.

Jim



This has been interesting dialog. I know Jim's background from being on
the forum for many years. I do not know yours. How about letting the
group know. For me, I was educated as an Electrical Engineer, but I have
been away from the true engineering for so long, I can just barely read
a schematic now.

--

Regards, Ross
C-172F 180HP
Sold
KSWI