[Amps] Quad Tube 4cx800 hf amp

Peter Voelpel df3kv at t-online.de
Sat May 27 09:12:44 EDT 2006



-----Original Message-----
From: R L Measures [mailto:r at somis.org] 

>> Again, if I drive a 8171 to not more then 1,5KW output ever,
>> it should be tuned for that power, not for 20KW

>However, if an 8171 is tuned for max suds in AB1, it is easy to back  
>the mic. gain down to the point where it produces 1500w in Class A --  
>resulting in superb linearity.  In the event that more power is  
>needed to communicate, one merely advances the mic. gain.  In the  
>event that 1500w is too much, one can run barefoot or turn down the  
>mic. gain even more.  

Very true.

However, if the design goal is a clean signal in class A at 1500W output
only and never more, it would be a silly idea to use parts sufficient for
20KW out, like large capacitors, coils, and power supply items, 1 5/8 EIA
antenna connectors, cables and relays etc. just to tune it up at 20KW and
then turn drive down via mice gain to 1500W.
It would be a far better idea to design it for 24h/year RTTY at 1,5KW and
use the TRX at medium output for best linearity, preferable in class A as
well.

73
Peter

 





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