[Amps] 6M 8171

[2]

> 2 at vc.net wrote:
>
>
>> ’Ǩ  The RL of an 8171 is c. 1200’Ä°, so, at 50MHz, a total C-Tune of 
roughly 
>
>
>> 80pF is needed for a Q of 15.  Since the anode-screen C, stray C, and the 
>> neutralizing bridge total c. 30pF, a 50pF Tune-C should do the job.   
>> 
>
>I guess that value of RL is at 15KW output power, so at 1500W
>it will be much higher and C-Tune need to become  much smaller
>
1200-ohms of RL would also be the case at 1.5kW out if anode supply V and 
anode A remained in the same ratio.
**   The standard of veracity about moonbounce amplifiers was set c. 
42-years ago when the ARRL reported that the first amateur 2-way 
moonbounce was accomplished with 1000 DC-W input.  As I understand it, 
the power input to the klystron amplifiers used to amplify the 1296MHz 
signals was c. 2500W.  Since the efficiency of such amplifiers is c. 40%, 
the acual power used to perform the feat was c. 1000W -- which is now 
perfectly legal under current FCC rules.  
**    It is my opinion that a 1500W limit for 6m moonbounce is not 
reasonable due to antenna beamwidth limitations.  +10db is easier to get 
with an 8171 6m amplifier than with a 6m antenna aimed at a 0.5-degree 
target with poor reflectivity.  

cheers, Peter

-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
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