[Central-Electronics] RE: Vintage Ham Shack for Sale - Includes 100V

[Jim candela]

Lyman,

    I sure appreciate your expert assessment on the 100v's performance.
Whoever gets that rig of yours will surely have a nice transmitter. I used
to work in various RF laboratories, both EMI testing, and engineering
development. I sure took advantage of readily available spectrum analyzers,
network analyzers, etc. for ham radio applications. That however ended 10
years ago, and lately I'm limited to my own test equipment. Sure I have some
good scopes, and a spectrum probe (1-100 Mhz), but as you guessed my
capabilities are pretty limited to dissect a HF transmitter's signal say
over 10Khz each side of the suppressed carrier. I find myself using
attenuators, receiver (AVC off, minimum bandwidth setting), and a AC VTVM
with DB scales. Pretty crude I'd say. I envy those that sophisticated test
equipment at their disposal.

	You said, "According to the panel meter, carrier suppression exceeds 60
dBc.  But
according to the spectrum analyzer, carrier suppression was on the order of
only 45 dBc or so."

	This is on par with what is achievable with a 20A if you stand on your head
while taping, and looking crosswise with one eye on the carrier null pots,
and the other on the magic eye tube. All my 6E5's and 6U5's are dim, as is
my 1629 that I modified the 20a for (socket & filament voltage change). As
you said these controls are not mechanically stable. The scope I use is a
Tektronix 2215 which is a better null indicator than the magic eye.

	I was wondering if you could explain to me how a 100V with typical 45dbc
carrier suppression can drive a 600L amplifier where the peak dive is around
5 watts PEP. It sure seems to me that dropping the 100V in power to 5 watts
from 100 (13 db) would erode the 45dbc carrier suppression to 45-13=32dbc. I
am assuming that the power is reduced by simply lowering the audio
microphone gain on the 100v. Maybe other means exist to accomplish this.
Since I'm 20A literate, and 100v ignorant, maybe you can help me make sense
of this situation.

Regards,
Jim Candela
WD5JKO

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