>
>Reference on Eimac's definition of the 3/2 power law.
>
>Page 97, Care and Feeding of Power Grid Tubes, copyright 1967 by Varian,
>third Printing 1978.
>
? You stated
"The 3/2 power law simply states that if you change all of the
interelectrode voltages applied to a power grid tube by a factor of 2,
that the current
will change by a factor of 2.8".
- - RE: "change all of the interelectrode voltages"? Eimac's
comments are only in regards to fixed screen potential and interpolation
between constant-current curves. . Fabricating "Eimac" quotes will
assuredly not earn high marks.
>Re: Pulling out of hat.
indeed
>
>Rich has cited the measurement method used and the results on the received
>end of one transmitted signal. However, he has never documented the
>equipment used at the transmitting station.
? The equipment used at the transmitting station was never a
consideration. Measurement of transmitted distortion was the whole
ballgame.
- Ham radio distortion measurement: Once upon a time, on 75m SSB, when
Challenger fell into the Atlantic, I happened across NBC's science
advisor, K6DUE, Roy Neal, and another chap. Roy was driving a solid
state amp - that was designed for 50w drive - with a 100w exciter, and
generating bad news splatter. . I broke in and asked Roy if he was
interested in a distortion measurement. He said yes and I gave it. .
Then the other guy comes to Roy's defense and tells him that his signal
absolutely vanishes when he tunes away 500Hz. .
>From earlier statements, I am
>advised that it was Norm, W6EDD at the transmitting end. One published
>circuit from Norm is a G2DAF variation.
? I would like to see this circuit. Who "advised" you.
>That circuit has a substantial flaw
>and would have to splatter.
? Any grid-driven amplifier that runs substantial grid-current generates
substantial distortion.
>Publication of this circuit would indicate that
>Norm did not understand the G2DAF circuitry and did not understand linear
>amplifiers in general. That circuit would have to distort.
but of course.
> Perhaps Norm
>tried the genuine G2DAF circuitry, but his carelessness in publishing
? where is Norm's circuit published. thanks.
>
> a defective circuit - which was claimed to be clean - would cast doubt about
>any of his work.
? Hardly. Most people know that Norm eventually came up with an
amplifier that produced acceptable distortion -- pretty much as clean as
the rest of the amps on the Combat Zone. Arriving there required no
grid-current and c. 350v of fixed screen potential
> So, reception of his signal using his unspecified and
>undocumented equipment under his unknown operating conditions is what I call
>"pulling the numbers out of a hat". Arriving at inflexible conclusions
>based upon this sort of test and documentation is unscientific.
? From experience, I know that the only distortion test that is valid is
unannounced, on the air and minimally scientific. . It is well know
that well planned Scientific (two-tone) distortion tests tend to produce
pretty good results.
>
cheers, Colin
- Rich..., 805.386.3734, www.vcnet.com/measures.
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