[HomeBrew] 50 ohm dummy load

[Ron W4BIN]

   Mr Joseph N1KBH Wonoski wrote:

> Hi all,   There are dummy load resistors on eBay for ~$2.00 depending 
> on the dealer and the claim is for 150 watts dissipation. They're ~1" 
> long apparently meant to be mounted on a heatsink.   Do you believe 
> the power rating allowing for a suitable dutycycle of course?   Have 
> any of you used them and can relate experiences? Thanks Joe N1KHB

   I do not know, if I were interested in using these for HF I would 
purchase one and test
it at 30.00 MHz with a VNA for reactance, to see if it is all resistance 
and no inductance.
   If I were interested in using these for VHF or above I would purchase 
the two terminal
non-inductive resistors that pretty much look like TO220 medium power 
transistors with two
leads and a mounting hole, sold by semiconductor dealers, connecting 
them in a series+parallel
arraignment on a huge heat sink.  Possibly four 200 Ohm resistors in 
parallel mounted with
all of the leads meeting in the center.  (distributing the heat as far 
away from the center as
possible)
   These little black plastic loads is all that I have ever seen in 250 
Watt UHF amplifier modules
as combiner reject loads.  (and such)
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