Good for AM, CW, RTTY and FT8, horrible for SSB due to low amplification
factor, heavy drive requirement and horrible IMD
It would be like using a 5867 or 5868 in place of a 3-500Z and 3-1000Z.
It is strictly a ISM tube..
About 10 years ago I removed a PP 250TH AM RF deck and installed PP 6C21's
running as 450TL's.
The 250TH's were converted first to grid driven linear config and next to
GG. I used 40M only, the original grid coil and a HB input network for GG.
The bias supply was regulated and adjustable. HV was varied from 2000-3000V
In all Class B GG tests the drive needed was higher than my TS-940 could
produce so that was cranked down and into a SB-200 I had kicking around.
IMD in all cases was horrible at anywhere near the 600W output level,
around -18-20dB 3rd real IMD as per the commercial/military way of testing
and not the silly ARRL method.
At about 400W out and in AB1 they looked decent and in the -25 to -28dB
range. They simply did not like grid current.
Maybe at 4000V (within ratings) it may have been better but I did not have
that PS in the small test rack.
In Class C 1500W CW or AM carrier (pushing it a bit hard with modulation at
~3500W PEP but wanted to confirm full emission tubes) was easily attained.
I built my first PP 250TH amp at 17 while in HS using military surplus thru
the MARS program plus roaming the shops in NYC Radio Row on Saturdays. It
was a short drive from LI.
Carl
Ham since 1955
----- Original Message -----
From: "Joe" <nss@mwt.net>
To: "MU 4CX250B" <4cx250b@miamioh.edu>; "Yueh Hsu" <hsu4qro@gmail.com>
Cc: "Amps" <amps@contesting.com>
Sent: Sunday, January 12, 2020 1:21 AM
Subject: Re: [Amps] anyone build an amplifier use 6T51 glass buble?
2 KW+ OUT for 100 bucks?
Hmmmm?
Joe WB9SBD
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 1/11/2020 9:50 PM, MU 4CX250B wrote:
A cool tube, Hsu, kind of a throwback to the 1960s, when homebrewers
were running 3-1000Zs and grounded grid 4-1000As. This is a BIG old
triode that I bet is a beauty to see lighted up with that nice
tungsten filament and plate glowing orange.
73,
Jim w8zr
Sent from my iPhone
On Jan 11, 2020, at 7:28 PM, Yueh Hsu <hsu4qro@gmail.com> wrote:
The datasheet here http://www.boezk.com/download_en/FU6051_EN.pdf, its
mu=48,not too bad. it is a cheap tube . the manufacturer's list price
only
$100+....
Hsu
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