I agree, the tuned circuits in this amplifier do look not very optimised...
However, the solution may be closer than we think, look up the G6JP
single 4CX250B 144 MHz PA in the RSGB VHF Manual, redesign the
grid and plate tuned circuits for 50 MHz, and you are all set.
Another design that may be worth investigating is the 4X250
multi-band amplifier in the Orr & Johnson VHF Handbook (1956).
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: "Skram, Helge (GE Healthcare)" <helge.skram@med.ge.com>
To: "Karl-Arne Markström" <sm0aom@telia.com>; "Ken G3WCS" <amps@g3wcs.com>;
<amps@contesting.com>
Sent: Tuesday, October 12, 2004 3:08 PM
Subject: RE: [Amps] Looking for a design for a single 4cx250b tube on50Mhz-Six
Meters
> The input circuit for the Geoffrey Brown 4cx250b 50MHz amp seems strange to
> me.
> A made a similar amp using 8122 and changed the input to W2GN style.
> That was easy to adjust for perfect input swr at desired gain.
> Can't find the link now,but can make diagram if you want.
>
> 73 de LA6MV
> Helge
>
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]On
> Behalf Of Karl-Arne Markström
> Sent: 11. oktober 2004 21:22
> To: Ken G3WCS; amps@contesting.com
> Subject: Re: [Amps] Looking for a design for a single 4cx250b tube on
> 50Mhz-Six Meters
>
>
> How about this one?
>
> http://www.btinternet.com/~geoffrey.brown3/4cx.html
>
> 73/
>
> Karl-Arne
> SM0AOM
>
> ----- Original Message -----
> From: "Ken G3WCS" <amps@g3wcs.com>
> To: <Amps@contesting.com>
> Sent: Monday, October 11, 2004 8:39 PM
> Subject: [Amps] Looking for a design for a single 4cx250b tube on 50Mhz -Six
> Meters
>
>
> > Hello all,
> >
> > I am looking for a design for a six meter amplifier using a single
> > 4cx250b tube. A URL on the web would be great. I have searched quite a
> > bit using Google and can come up with several two and three tube
> > designs, but really I don't need that much power. 250W would be quite
> > enough.
> >
> > I did find a reference link from several web sites to the following URL :-
> >
> > http://user.itl.net/~equinox/4cx.html
> >
> > However, it doesn't seem to work any more, which is a shame as it looks
> > like what I am looking for.
> >
> > Any pointers to circuits or design most welcome.
> >
> > Thanks,
> >
> > Ken. G3WCS
> > --
> >
> > Ken Wood <ken@g3wcs.com>
> > IO83rh : Cheshire : NW England
> > (+44) (0)1606 892677 (home)
> > (+44) (0)7968 161632 (mobile & sms)
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
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