[AMPS] Carborrundum Resistors

[Will Matney <craxd1@ezwv.com>]

Larry,
Try adding a 30-33 pF doorknob cap to ground at the input of those 
resistors and see if it drops it. The old Collins dummy loads and some 
new ones uses this method to get rid of any inductance.

Will Matney


I have ten 890 AS carborrundum resistors. They are supposed to be 330
ohms 5% but they measure 400 to 500 ohms. Is it the norm that these
resistors change that much with age? Are they still ok to use for a
dummy load at there rated power ( 100 watts each, I think )??? All ten
of these guys parralleled come to 56 ohms. When I put the 259B to them
to check swrs, I end up with 1.3 swr at 2 MHz and 10 plus at 30 MHz.
With a variable 1000 pf capacitor in series, I can tune the swr 
to nil to about 24 MHz. Probably would tune above 24 MHz ok if the cap
had a lower minimum pf.  I'd like to make an air cooled 3 KW dummy load
from these if I could. 

Regards,
Larry N5BIp


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