[Amps] Tuned Input for G-G 50Mhz amp

[David H Craig]

    The Orr Handbook 23rd Edition lists it as 120 ohms on page 15-18.  I 
agree with Han-san, a Pi is best.  Forget the "T".

    Dave N3DB


----- Original Message ----- 
From: "Han Higasa" <higasa at plum.ocn.ne.jp>
To: <amps at contesting.com>
Cc: "JE1BMJ Han Higasa" <je1bmj at jarl.com>
Sent: Wednesday, March 24, 2010 9:19 PM
Subject: Re: [Amps] Tuned Input for G-G 50Mhz amp


> hi all,
>
> In the book "Linear amplifier design book for radio amateur"
> by Eimac I found "nominal input impedance of 3-400Z is 122 ohms".
>
> I also found "A 2 Kilowatt 3-400Z Linear for six meters" by
> William I. Orr, W6SAI in this book but it uses two 3-400Zs
> and direct feed via one 1000 pF coupling capacitor to both tubes.
>
> Another operating examples show the value around 100-130 ohms,
> and Cin is around 8.3-pF in GG configuration.
>
> I recommend pi (Q=2) with C1 = 122 pF, L = 0.15 uH and C2 = 92 pF.
>
> I am using a pi circuit for my kilo-watt amp for six meter and still
> experimenting a -VC(series)-L(series)-VC(parallel)-L(series)- type 
> circuit.
>
> See you soon on the band!
>
> de Han JE1BMJ
>
> ----- Original Message ----- 
> From: <4z4tl at iarc.org>
> To: <amps at contesting.com>
> Sent: Friday, March 19, 2010 7:11 AM
> Subject: [Amps] Tuned Input for G-G 50Mhz amp
>
>
>> Hello all
>>
>> Trying to decide between a "Pi" and  a "Tee" input circuit,  for a 50Mhz
>> single 3-400Z amp.
>>
>> (formerly AL-80A with 3-400Z and not the 3-500Z).
>>
>
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