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

[R.Measures]

>In einer eMail vom Fr, 26. März 2004 17:06 MEZ schreibt "R. Measures" 
><r at somis.org>:
>
>>
>>
>>>In einer eMail vom Do, 25. März 2004 18:21 MEZ schreibt
>>>frank_goenninger at t-online.de (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.  

>Peter
>
>