yes, with yours there will be no problem on 10m, the output Ra
is pretty low with 500 ohms and 130pf minimum c-tune are fine on 10m for a Q
of 12.
Chuck with one tube, the higher voltage and lower output needs a minimum
c-tune of 24pf on 10m at a Q of 12 which will be impossible to obtain.
73
Peter, DF3KV
Von: "PA3DUV" <pa3duv@planet.nl>
> Chuck,
>
> The DX2sp from Emtron uses a GU84B @ 2500 VDC on the plate. That unit
puts
> approx. 2000 watt.
>
> My own Emtron DX4 with 2 x GU84B and 3000 VDCD on the plates (under load)
> puts out approx. 6000 watt.
> At that Vp the Ip is approx 3.5 A
>
> The GU84B is a low Vp tetrode and has the advantage of a high filament
> voltage.
>
> Typical power gains achieved in my system are between 18-20 dB.
>
> There are a number of DX2sp owners on the yahoo Emtron forum who might be
> able to give you some more operational and constructional details of that
> single GU84B amplifier. http://groups.yahoo.com/group/emtrondx15/
> Also pictures and circuit diagrams of the twin GU84B amp can be found in
the
> file and picture archives on that yahoo group.
>
>
> Cheers, Dick
> PA3DUV
>
>
>
> ----- Original Message -----
> From: "Partain, Chuck" <Chuck_Partain@maxtor.com>
> To: <amps@contesting.com>
> Sent: Friday, January 06, 2006 3:20 PM
> Subject: Re: [Amps] my little amp project of many hours..maybe 50% done
>
>
> >
> > looking back, I seem to remember 4kv being the good fit on this tube.
> > Looking now that folks have more info, perhaps its a bit too high.
Looking
> > thru sites that list specs on it, I see 2.2-4.25kv listed as a suitable
> > plate voltage.
> >
> > With my PS sitting at 3900v no load(250k bleeder) what can I expect to
see
> > loaded? i'm sure I'll see drop. also I'm a bit concerned now with some
> > internal arcing
> > if it way too high?
> > Not as concerned with whats going on inside the case, i'm
> > designing/thinking of
> > heavier components on that side(tank/blocking/plate choke) anyway
> >
> > Any more thoughts?
> >
> > thanks.
> >
> >
> >
> >
> >>>Hi Chuck,
> >
> >>>I think your anode voltage will be a bit high.
> >>>The GU84B is a medium voltage, high current tube
> >>>and normally sees 2,2KV.
> >>>With the high impedance at 4KV you will run into
> >>>trouble on 10m as the bandswitch is a bit far away
> >>>and the minimum capacity of that tuning capacitor
> >>>will be not low enough for reasonable Q on that band.
> >>>If the ht-transformer has a center-tap I would go for
> >>>half the anode voltage
> >
> >>>73
> >>>Peter
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