[Alexandria Radio Club Reflector] your MFJ dummy load

[Ian]

Just tested an MFJ 300 Watt dummy load with an ohmmeter and discovered that
the dummy load was showing about 150 ohms when it should be very close to 50
ohms.  I tried two other ohmmeters (like radios, you can never have too much
test equipment) and got the same results.  So, like every other piece of ham
equipment I have, off comes the lid to see what's up.  Looks fine - no
evidence of overheating as if a previous owner keyed down with a linear amp.
Then it dawned on me - a lot of MFJ dummy loads use a big heavy-duty
cylindrical resistive element that's attached to the chassis on each end
with compression clips - the element just snaps in and out.  And between the
clips and the element lies the potential for corrosion which will increase
the resistance!  So after a few twists of the element to knock off any
corrosion the ohmmeters read 50 ohms again.  Might want to check your dummy
load(s) periodically.

73, Ian N8IK