>> From: Rich Measures <measures@vc.net>
To: <amps@contesting.com>
>> Date: Sat, 2 Aug 97 21:36:24 +0000
>>
>> Adding the extra tube is relatively easy. Correcting the ramifications
><SNIP>
>> adding a second tube is filter-C failure. When the second tube is added,
>> the 120Hz ripple current in the hv filter C doubles, which in turn
>> quadruples the (P=I^2*R) dissipation in the filter capacitor. Mostly
>> during contesting, case seams sometimes split and the oil leaks out.
>> Peter W. Dahl reportedly has a retrofit upgrade.
>> -It adds up to a lot of dollars, grief, time, and less than a half
>> S-unit.
>
>Strange.
You thought period=1/frequency and frequency=1/period was strange
>
>I just looked at a bone stock tank two tube Alpha conversion and it
>worked just fine.
>
In serious contesting service? .......With the stock tune-C and 2-holer
conversion, the tank Q is under 6 on 160m. The 160m output is reportedly
substantively less than 4kW. Apparently, you believe that a tank circuit
which is engineered for 2000 ohms in, 50 ohms out, will also work
properly for 1000 ohms in, 50 ohms out. I don't.
>Power output was good (about 4 kW) and harmonics were within reason.
>
>Are some Alpha's OK, and other's as bad as you say Rich? Or are all
>the stock tanks the same??
We are not discussing Alphas. We are discussing one model, the Alpha 77.
Who said all Alpha amplifiers are 'bad'. Different models have
different problems. The nearly perfect amplifier is apparently not being
built commercially.
- In your opinion, Mr. Rauch, do you feel that a Centralab 5kv 1000pF
Series 58 is adequate for the 77's load C 160m padder?
>
>Why do you think the tanks Q has to be higher than it is, if
>harmonics are OK?
>
When tank Q falls below a critical amount, the tank is incapable of
performing the needed Z transformation. As I recall, you pointed this
out to someone in a previous post on rec......homebrew NG.
Rich---
R. L. Measures, 805-386-3734, AG6K
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