[ETO_Alpha] Re:Question about alpha 77dx/sx amps

Wed, 20 Nov 2002 11:54:30 -0500

Hello Jim, Alan, etc.,
    I found I could use bottom half of 10 meters in my SX, and, with the
RFParts RFC3 choke (from Ameritron) I can use 12 meters as well.  Instead of
the 24-25 Mhz resonance, it has resonances at 12 Mhz (as advertized) and at
16 Mhz , not advertized, and works fine on all ham bands.
    I do find the tuning on 10 is limited to 28.5 +/-, with the vacuum
variable cranked all the way out.  The turns counter reads about 23.7 and
bottoms out at 99 fully meshed.
    I hope this helps.  73,    George    K8GG


----- Original Message -----
From: "Alan Gray" <[email protected]>
To: <[email protected]>; "James C. Garland" <[email protected]>;
<[email protected]>
Sent: Wednesday, November 20, 2002 11:15 AM
Subject: Re: [ETO_Alpha] Re:Question about alpha 77dx/sx amps


> Jim,
>
> The 77SX is useable in part of the the 24-30 mhz range. Mine works fine on
> 10M but isn't useable on 12M. This is not because of the output
capacitance
> with the 2 tubes; rather, the self resonant frequency of the plate choke
> (approx 25 mhz)  prevents use on 12M.
>
> Alan, W3BV
>
>
> ----- Original Message -----
> From: "James C. Garland" <[email protected]>
> To: <[email protected]>
> Sent: Wednesday, November 20, 2002 6:02 AM
> Subject: [ETO_Alpha] Re:Question about alpha 77dx/sx amps
>
>
> > Positions A and B on the 77Dx/Sx amps are prewired for 1.8-2.0 MHz.  The
B
> > position has extra loading capacitance.
> >
> > The other bands are: 3-5 MHz
> > 5-8 MHz
> > 8-12 MHz
> > 12-18 MHz
> > 24-30 MHz  (this band not available on the 77SX, because the output cap
> > of the two tubes is too high)
> >
> > 73,
> > Jim W8ZR
> >
> > _______________________________________________
> > ETO_Alpha mailing list
> > [email protected]
> > http://mailman.qth.net/mailman/listinfo/eto_alpha
> >
>
> _______________________________________________
> ETO_Alpha mailing list
> [email protected]
> http://mailman.qth.net/mailman/listinfo/eto_alpha
>
>