>
>nospam4me@juno.com wrote:
>>
>> Hi Charlie,
>>
>> Glad to see you going with the g-grid circuit. You'll find the 4-400
>> amplifier
>> slightly harder to drive vs the similar 3-400/3-500Z.
>
>It took me awhile to "see the light", but I think that I'm now on
>track! Tnx!
>
>> I have most of the input circuits for the common tubes, the trouble is
>> the
>> paperwork was done before solid state final exciters. The lower Q of the
>> older designs plays havoc with some exciters. I've seen a real
>> interesting
>> oscillator made from an early SS exciter final where one wasn't wanted.
>>
>> I'm in process of rebuilding my personal SB-220 with all the current
>> fix's,
>> during last nights late night tune up into a termination, I measured the
>> factory SB-220 swr using my TS-940. The best obtained was about 1.6 to
>> 1 sweeping the entire 80/40/20 meter bands. Although my 940 seems to
>> drive it fine, "your results may vary."
>
>I don't have any problems driving my SB-220 with my TS-930. I'm hoping
>that will stay the same with the gg 4-400's.
>
? When a G-G amplifier is driven with roughly 1w, the input Z is way
different than normal. However, when the driving power is around half of
normal, the input Z is almost normal.
The TS-930 auto-tuner has the advantage of operating at half-power
during tuning. Later model transceivers have the disadvantage of
auto-tuning with roughly 1w.
cheers
.
- Rich..., 805.386.3734, www.vcnet.com/measures.
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