>> We are always urged to tune for maximum power out at maximum drive. For
>>SSB, I tune my FL-2100B (you guys already know this has 572B's) with 100
>>watts drive
>
>? Max drive for 2, 572Bs is c. 65W.
>
>@@ OOPS - I believe that is 65 watts per tube,
? Approx. 30 - 35W per 811A or 572B.
> .so at 100 watts drive, each tube gets 50 watts.
>
>>>at ~50 dots per minute (or whatever the max. of my keyer is) for
>>>maximum output, which is usually around 800 watts A0 into a dummy load.
>>
>>Now, for AM, RTTY, or some constant carrier mode, should the drive from the
>>exciter be reduced without retouching up the tune/load controls?
>>
>>/ For AM, Yes. Even though the AM carrier is only 25% of PEP, the
>>loading will be right at 100% modulation peaks.
>
>@@ Interesting perspective. I can see that point.
>
>>>I typically repeak the output of both transmitter and amplifier when I
>>>reduce the power. This gives more power output with less plate current.
>
>>>The Plate control doesn't change much, but the Load reduces a lot when
power is
>>>reduced.
>>
>>/ An amplifier needs to be tuned for the max PEP it will be used at.
>
>@@ What about RTTY, SSTV, PSK31, etc where you drive it with audio from a
>sound card?
/ The same. An audio tone produces a discrete RF frequency in a SSB
transmitter.
>I haven't actually use the amp for that yet, but the same principle
>would apply to the sweep tubes in my transmitter. Would you peak the
>plate/load for max out at the reduced drive or tune for max power at max
>drive, then reduce power to a safe plate current.
/ No. Reducing drive and tuning produces a mis-tune = non-linearity.
>The power out will
>definitely be less with more plate current. That sounds like a lot less
>efficiency - wasted power in the tube - read HEAT.
>
>Thanks for the reply and 73's.
>
ur welcome, Rick
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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