[Elecraft] Dummy loads for dummies
Edward R Cole
kl7uw at acsalaska.net
Wed Dec 28 03:26:20 EST 2016
http://www.kl7uw.com/2M80_inside_1.jpg
In the photo the large black square at bottom of the pc board is a
surface-mount 56-ohm 35w resistor (good at 2m) and available from
Mouser. I believe there were 51-ohm values also. This used in a
23-dB pi-attenuator to take 10w down to 50mw for driving a Toshiba
SAV-36 RF amplifier module in the 80w 2m amp that I build. W6PQL
sells 150w surface mount loads that are good at 1296 MHz. All you
need is a small pcb and a large heat sink.
TO-220 form probably more convenient as one can mount them directly
to a heat sink with a tapped hole for a 4-40 machine screw and using
a little heat sink compound. If the heat sink is large enough air
cooling is sufficient.
I have a big old Sierra Electronic 500w coaxial load with heat sink
and built in power meter; weighs about 40-50 lbs; makes a dandy door
stop, too! It is rated to 1000-MHz. Got in trade somewhere? I
would not want to pay retail for one; probably in range of $2/watt.
73, Ed - KL7UW
http://www.kl7uw.com
Dubus-NA Business mail:
dubususa at gmail.com
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