[AMRadio] Re: 1930's Old Buzzard Open Rack Transmitter Finally Sees


ne1s ne1s at neandertech.com
Thu Feb 23 16:41:35 EST 2006


Sorry!!! 

That was supposed to read "Could you or DON describe the protective bias 
circuit you refer to? " 

 -'1S 

ne1s writes: 

> Thanks for the kudos, John!  
> 
> Could you or done describe the protective bias circuit you refer to? 
> Probably could figure it out, but the group may be interested as well...  
> 
> 73,
> -Larry/NE1S  
> 
> John E. Coleman (ARS WA5BXO) writes:
>> CONGRADULATIONS A JOB WELL DONE!
>> 	I really like the choice of tubes.  I don't know what a T55 is but
>> probably one of the special Taylor triodes with 55 watts plate 
>> dissipation.
>> Probably not a lot different than the 812s but I know that the 812s are 
>> very
>> good tubes to use in a class C plate modulated rig especially if used 
>> with
>> 100% grid leak bias or the configuration that Don, K4KYV, uses where 
>> there
>> is a safety bias supplied thru a diode and the diode becomes reversed 
>> biased
>> when RF drive causes grid leak bias.  The 100% Grid leak bias DOES make a
>> difference in the modulation characteristics of the rig.
>> John, WA5BXO 



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