Dear Elecraft reflectorees....
I have received some good (private) replies to my query about the need
for accuracy and I've learned a lot about how other think.
Shown below is one reply that I feel is worth sharing. I'm not an
engineer, so I found this to be especially enlightening. I assume
some (many?) will cry sacrilege, but since this is not me speaking,
don't yell at me. I'm only the piano player!
[snip]
I do have to chuckle when I read about these accurate measurements on a Bird
wattmeter. Back in the 80's when I was involved with RF generators, we used
Bird slugs in the power monitoring section. We used a calorimeter to
calibrate the slugs. It was not uncommon to have the slugs off by as much as
60%! We had a box of over 200 slugs that were too far off to try to
calibrate. We threw them out. Should have saved then and sold them at Ham
fests. Would have been a good laugh when someone said they checked their
power with a Bird meter.
Had one customer who called and bitched that his new 13.56MHZ 15KW generator
was putting out only 12KW at max power. He had tried two new Birds and they
read the same thing. Since we designed the 15KW generators to run continuous
at 18KW, we took our 13.56MHZ 20KW calibrated Bird to the customer. We
showed him that at the 15KW setting it was putting out 15KW and that when at
maximum as he was checking it, it was putting out 18KW. He was embarrassed
with his new Birds.
[end snip]
Comments?
de Doug KR2Q
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