[Johnson] A question from A New BA operator.

Thu, 21 Mar 2002 10:43:02 -0500

Always run the 6146's at their rated grid drive voltage. Loading up the
Valiant to full power and then using the grid drive control to reduce
power is wrong. It will cause AM distortion and drastically reduce the
life of the tubes. If you want to reduce output power, put a 3, 6, 8, or
10db pad between the transmitter output and your antenna. A less
attractive way, and not normally recommended, would be to put a variable
pot for the screen resister of the driver tube. Always run the output
tubes at their rated grid voltage.
Pete,WA2CWA

On Thu, 21 Mar 2002 09:12:55 -0500 "Ray, W2EC" <[email protected]>
writes:
)........
> 
> Another thought, and I haven't tried this, is to load the Valiant up 
> to
> full power (330ma for AM, 450ma for CW), peak the grid then back off 
> the
> grid drive (normally 8ma) until you get the power level you want.
> 
> 73, Ray  W2EC  
> 
> "Guy Olinger, K2AV" wrote:
> > 
> > Correct. Run it at specs.
> > 
> > The plate voltage is fixed, the screen voltage is fixed, the L/C
> > ratio's in the tank circuit are only partly variable since the L 
> being
> > used on a given band is fixed. The whole shebang is at maximum
> > efficiency at the specified settings.
> > 
> > I've seen guys operate a Valiant AM until the cows came home. 
> Just
> > don't drop a book on the mike switch and get up and leave. When 
> your
> > voice starts to hurt let the other guy transmit :>)
> > 
> > ----- Original Message -----
> > From: "Dr. Clifford L. Coleman" <[email protected]>
> > To: <[email protected]>
> > Sent: Wednesday, March 20, 2002 4:23 PM
> > Subject: Re: [Johnson] A question from A New BA operator.
> > 
> > > While restoring my valiant, I found(as the manual suggests ) 
> that
> > less
> > > loaded causes high modulator current-so I tune it up to full 
> power.
> > cliff
> > > k9jts
> > > ----- Original Message -----
> > > From: "Mullin, Edward J." <[email protected]>
> > > To: <[email protected]>
> > > Sent: Wednesday, March 20, 2002 1:40 PM
> > > Subject: [Johnson] A question from A New BA operator.
> > >
> > >
> > > > Hello All,
> > > >
> > > > I've been lurking on this mail list for a while, as I've been
> > > > working on my Valiant.  So far I have gotten it working 
> again,
> > (recapping
> > > > and replacing a couple of tubes was all it needed:)   Now I 
> want
> > to use it
> > > > on the air.  (I've been testing into a dummy load during
> > restoration). I'm
> > > > new to BA's (and Ham operations) in general, and  I've been
> > reading the
> > > > manuals alot.  What I want to know is: What is the correct 
> method
> > for
> > > > transmitting at less than full power. The manual is good at
> > describing the
> > > > tuning process, but it doesn't really cover this 
> information.(at
> > least I
> > > > didn't figure out where it was.)
> > > >
> > > >
> > > > 73 de KB1HYS
> > > >
> > > >
> > > > > Edward Mullin
> > > > >
> > > > >
> > > > _______________________________________________
> > > > Johnson mailing list
> > > > [email protected]
> > > > http://mailman.qth.net/mailman/listinfo/johnson
> > >
> > >
> > > _______________________________________________
> > > Johnson mailing list
> > > [email protected]
> > > http://mailman.qth.net/mailman/listinfo/johnson
> > >
> > 
> > _______________________________________________
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> _______________________________________________
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> 

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