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Re: [Amps] Re: GU-84b: Drive power required for full power output ?

To: ("R. Measures"),, ("\" AMPS\"")
Subject: Re: [Amps] Re: GU-84b: Drive power required for full power output ?
Date: Fri, 26 Mar 2004 21:01:24 -0500
List-post: <>
 "R. Measures" <>wrote:

>>In einer eMail vom Fr, 26. März 2004 17:06 MEZ schreibt "R. Measures"
>>>>In einer eMail vom Do, 25. März 2004 18:21 MEZ schreibt
>>>> (Frank Goenninger):
>>>>>I initially intended to ask if about 1A of input current will be enough
>>>>>to really get reasonable power output?
>>>>>This comes from a simple calc from Pout of the TRX, which is about 100W
>>>>>producing about 1.4 A of current into 50 Ohms.
>>>>>Also, for this tube, what type of input circuit would you recommend when
>>>>>trying to cover all bands up to 30MHz ?
>>>>Hi Frank,
>>>>Since this is a tetrode it will be run without grid current,
>>>>the driver does not need to deliver current, just voltage.
>>>>Typically the grid is loaded with a 50 Ohm dummyload, into
>>>>which drive voltage developes without tuned circuits.
>>>>For the higher bands you probably have to compensate the high
>>>>input capacity with a small coil in parallel.
>>>>I guess you will need not more then 25W drive for full throttle.
>>>?  My guess is that with a 50-ohm termination, somewhat more than 25w
>>>will be needed to drive the grid up to the 0v point.  The grid potential
>>>is typically -80vdc.   64w is needed to produce 80v-pk across 50-ohms.
>>>cheers, Peter
>>you are probably right Rich, but full throttle in Germany means 750W
>>output not 3500W ;-)
>?  200kpH+ on the autobahn, 750w on the air hardly sounds equitable.

from more then 10W EIRP upwards you have to file drawings
and declare how high signal strength is in the environment,
proofed either by calculation or measurement

the ham lobby obviously is just not large enough

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