[Amps] 20kw Dummy load?

[Tony King]

Robin,

What frequency do you want to use to test the amp? You said you wanted a 50 
ohm, 50 MHz load. You could use 20 can style 1 KW dummy loads with a power 
divider made from 39 inch lengths (quarter wave or odd multiples) of 70 ohm 
solid dielectric coax and tee connectors for 50 MHz. This isn't all that 
impractical at 50 MHz but would be a big pile of coax at 3.5 MHz. This will 
make you a very frequency selective dummy load but if you only want to test 
on one frequency/band, this might offer you a simple and inexpensive 
(relative to the cost of a "real" 20 KW load) solution. No boiled bugs but 
no huge expensive parts either.

73, Tony - W4ZT

At 05:06 PM 8/12/2004, Robin Szemeti wrote:
>Hi,
>
>I need to use / beg / borrow / steal a decent dummy load to test this
>amplifier out .. running into its intended load I've had a couple of DC
>flashovers *somewhere* and I'd like to run the amp up into a dummy load, just
>to prove it to myself  ...
>
>anyway ... has anyone got, for loan or whatever, a 50 ohm, 50mhz dummy load,
>capable of standing around 20kw CW for at least 5 minutes, water cooling is
>OK, we can do that.  Ideally it should be 3 1/8" EIA flange,  but I'm
>prepared to get busy on the lathe to make up a fitting if I have to.
>
>Actually, Id even settle for a gigantic 50ohm resistor that I could watercool
>myself, not averse to a bit of lathe work to make a water jacket for it. Are
>normal carbon tubular ceramic resistors OK in a water jacket or do you  need
>'special' ones btw?
>
>I'm UK based ...
>
>--
>RapidCut CNC Technology
>
>CNC Plasma Cutter
>http://www.rapidcut.co.uk/
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