-----Original Message-----
From: amps-admin@contesting.com [mailto:amps-admin@contesting.com]On
Behalf Of Richard
Sent: 01 July 2002 23:34
To: AMPS
Subject: Re: [Amps] 4CX250 IMD
>
>
>> Compared to poor regulation, yes. Compared to a well-engineered zener
>> shunt screen regulator, probably not a significant improvement. To
>> arrive at good linearity with a 4cx250B/R/BC/7203, load for less screen
>> current, use maximal anode supply V. and add c. 5-ohms of RF-NFB R in the
>> cathode (Rk). See Fig 10 on my Web site.
>>
>> >G3SEK is vacationing in the states at the moment, but he gets
significant
>> >improvement in IMD suppression with the tube by holding the screens
>within
>> >millivolts using active regulation.
>
>You might take a look at his website, he compares the active regulator to
>the active regulator with an 150 ohm series resistor to raise the impedance
>of the regulation, (Probably no worse than the Z of VR tubes or zeners) and
>a zener string with 100 uF to stabilize the transients (By far the worst of
>the three tests).
** Would you trust a stock buy recommend from a brokerage that gave
salesmen a commission on stock sold?
Huh what does that mean?
>These were actually done with voice modulation and a hold
>Spectrum Analyzer and done by GW4FRX. I use it on a 4CX1500B and exceed the
>Eimac specs for the tube. (Two tone, I can't do the same test that FRX can
>do.)
** A two-tone imd test is about as useful for evaluating splatter as
teats on a boar hog.
Agreed!
Conrad G0RUZ
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