[UK-CONTEST] OT 4xc350 BIAS

[Richard Staples]

Hi all

The NAG suffered from many design problems

The HT was way too low ...in fact if I remember right there were 2 versions a 
"low" volts and " high " volts ..200 v in between them both lumbering around 
1500 - 1700 v .

The screen had no regulation at all as I recall with a passive grid input 
..designed for a 10 w drive ..all this coupled together made for a pretty poor 
signal as the "instinct" of most NAG users was to drive the nuts off it to try 
and achieve the quoted output power.....hence poor signal

The 350f ( original I think that was in it )  sings like a bird with a decent HT 
on it ...2 kv+ ...so I built a proper PSU for it to sit on and it worked great.

Standing current ?  most designs using 350's seem to go for 100 ma in AB1 with a 
high cut off volts at -120 I think.

Cheers Richard G4HGI





________________________________
From: Neil Ackerley <neil.ackerley at bcs.org.uk>
To: ALEX LISTER <alexcom22 at btopenworld.com>; uk-contest at contesting.com
Cc: GeoffFindon <g.d.findon at btinternet.com>; regwoolley at aol.com
Sent: Tue, 14 June, 2011 14:42:58
Subject: Re: [UK-CONTEST] OT 4xc350 BIAS

Alex,

What range of standing current do you have with the POT adjustment.

I believe you need 100mA standing current for a 4CX350 for SSB.

Neil, G3RIR



-----Original Message----- 
From: ALEX LISTER
Sent: Tuesday, June 14, 2011 1:49 PM
To: uk-contest at contesting.com
Cc: GeoffFindon ; regwoolley at aol.com
Subject: [UK-CONTEST] OT 4xc350 BIAS





Please dont laugh but I have a very ancient NAG 144 Linear (NOT!) Amp.
Seems to work OK at the 200 watt plus level. So I assume valve is OK.

Only odd thing is the BIAS contriol Reading in  the Jinglish handbook says 
set to 40 ma for 4CX150 or 350 (Mine has 4CX350)
Full adjustment of POT only allows me to set for 50ma
Does it matter,

Have I a fault or is the info wrong.
Might be easier if  book was in English !
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