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

[DF3KV at aol.com]

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 ;-)

73
Peter