[Johnson] Question on a Valiant.

Mon, 8 Jul 2002 13:16:59 -0500

According to the manual it should be 150 out on AM and many Valiant owners I
have talked to say 130 - 145 is normal.
Still looking for answers, going to the shack now to take some voltage
readings. More to follow.

Thanks & 73's Dutch
Please visit my Collins web-site
http://users2.ev1.net/~wb7dyw/
And my new R-390 Page.
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-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Ray, W2EC
Sent: Monday, July 08, 2002 10:16 AM
To: Johnson@Mailman. Qth. Net
Subject: Re: [Johnson] Question on a Valiant.

According to the manual, the Valiant HV PS is rated at 660vdc noload,
600vdc at full load. So using a value of 680vdc to calculate the numbers
is highly optimistic. I haven't measured mine lately, but I will. I do
recall about 120 watts out on am (330ma) and about 160 watts on CW (and
on peaks when running the SSB adapter). These numbers are close to what
Dutch had (115 and 150 watts) and fall well within the tolerance range
of the various wattmeters. To say he is WAY short on output is a little
strong, I think, based on the factory specified HV levels and current
indications. Any number of factors could reduce the efficiency from the
expected 75% (that is what the manual seems to indicate) down to 60 to
65% which is what Dutch and I seem to be getting. Mine is all original
(I bought it brand new around 1961) with all original tubes. Only part
replaced is the screen drive variable resistor in all these years. I
guess it can be expected to be a bit tired by now.

73, Ray  W2EC

"Guy Olinger, K2AV" wrote:
>
> He's WAY short on output for ANY of those configurations, screen or no
> screen current. Still need to know his plate voltage and then possibly
> into other issues.
>
> We always used the 75 watt setting for CW. Felt "easier" that way.
> Back then the 6146's were a steep little pile of cash for us folks.
> Burning out a set meant going back to the 807 rig and saving money for
> a while.
>
> 73
> ----- Original Message -----
> From: "Glen Zook" <[email protected]>
> To: "Guy Olinger, K2AV" <[email protected]>; <[email protected]>;
> "Johnson@Mailman. Qth. Net" <[email protected]>
> Sent: Sunday, July 07, 2002 8:52 PM
> Subject: Re: [Johnson] Question on a Valiant.
>
> > Remember, on the Valiant, as on most "boat anchor"
> > transmitters, you are measuring cathode current and
> > not plate current.  Cathode current also includes the
> > screen current which must be subtracted to get true
> > plate current.  Each 6146 draws about 12 mA of screen
> > current.  Thus, you have to have 330 mA plus about 36
> > mA which is 366 mA at 681 volts for 225 watts input.
> >
> > Also, remember that the 6146 is rated at a maximum of
> > 67.5 watts input for AM operation.  For 3 of them, the
> > maximum input should not exceed 202.5 watts, and
> > running at this power level will greatly reduce the
> > longetivity of the tubes.  They are much happier at no
> > more than 60 watts input on AM and no one can tell the
> > difference at the other end.  However, the tubes will
> > last several times longer.
> >
> > On CW, the maximum power input is 90 watts, or 270
> > watts for 3 tubes.  Again, cutting this back to about
> > 75 watts input will greatly increase the tube life.
> >
> > The power figures are directly from RCA as published
> > in various tables in advertisements in QST, etc.
> >
> > Glen, K9STH
> >
> >
> > --- "Guy Olinger, K2AV" <[email protected]> wrote:
> >
> > 225 watts input with 330 mils would require 681 volts keydown.
> >
> > =====
> > Glen, K9STH
> >
> > Web sites
> >
> > http://home.attbi.com/~k9sth
> > http://home.attbi.com/~zcomco
> >
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