[Antennas] RF Exposure.. Hoooey....or otherwise

2002年3月23日 13:49:14 -0600

Me thinks Hooey about sums it up.
Or maybe its that new math stuff... E times I times number of joints smoked...
I don't claim to know everything there is to know about transmitters, but... I
have been a radio engineer for almost 20 years and a ham longer than that. If
they can STUFF 70+KW worth of power supply and amps into a conventional vehicle,
the Harris' or Broadcast Electronics or Collin's or Contentiental's of the world
will want to talk to them. I work on a 25kw AM TX that the power supply alone
weighs almost 2000 lbs. I work on several 30-35kW FM TX's that the power
supplys weigh in EXCESS of 2000 lbs and are about half the size of a vehicle. 
And that is with a 240 volt Delta AC service. 
Not to mention that in one of the clips a guy (Dave?) was describing the tubes
in a couple of amps and he was talking about 3-500Z's and 2 of some type of
"3000's". Granted, the "3000's" tube is probably a 3000 watt plate disipation
tube that with proper cooling (about 80 CFM) COULD (not likely but could) make
about 6000 watts in Class AB service. OK a pair _could_ make 12kW with proper
power and cooling but I didn't see any evidence of any serious cooling or of
much power supply other than a bunch of alternators.
A local CBer called me one day wanting help building an amp to participate in
the CB shootouts. He wanted it to put out 20kW and be vehicle powered. When I
had HIM do the math on power supply voltages and currents he was a bit
chagrined. I think it was about 2500 amps at 12 volts. In addition to the
railroad alternators you would need rail road tracks for power busses.
Crawling back under my rock now.
Wayne Dahl wrote:
>> Want to see some really stupid people doing some really stupid
> things? Check out this page. http://www.bigradios.com/avis/ Be
> warned...if you download the AVI's, you'll need either a lot of time (start
> the download, go out for a pizza and some beer) or a broadband connection.
>
-- 
Later,
Kevin
WD4RAT
mailto:[email protected]
KK BROADCAST ENGINEERING
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AM GROUND SYSTEMS CO.
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