> 2@vc.net wrote:
>
>
>> ??? The RL of an 8171 is c. 1200???, 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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