Charlie,
When I was poor man 40 years ago, I always wanted Tektronix 545B Scope,
which I couldn't afford. So I built a "Chinese Copy" with discarded parts
from the Calibration department of the computer company I worked for. The
scope use many 6DJ8s. I did get it working after about a year; not bad for
some one with no formal electronics training!!!! Tektronix were very helpful
in supplying some critical parts. Looking back I must have been mad, but it
was one hell of away to learn how these things work.!!!!
Bye the way I manufacture a special Head Amplifier for the KAZ and other
Flags. This has 1100 Ohm input matching/isolation transformer, about 20dB
gain and a less than 1dB NF and uses 8 x J309s plus a string of 1N4148
limiting diodes. Wellbrook FLG100LN. There are about 70 units in service
mainly in the US with MW Dxers.
73
Andrew G8LUG
----- Original Message -----
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
To: "'Andy Ikin'" <andrew.ikin@btopenworld.com>
Cc: "'Topband Reflector'" <topband@contesting.com>
Sent: Sunday, August 25, 2013 10:29 PM
Subject: Re: Topband: Anyone have a boat load of J-310s?
Yes, we could swing the grids of those tubes quite a ways before
encountering enough non-linearity to produce a significant amount of
intermod, Andy! The old original AMECO tunable vacuum -tube preamp, that
I
borrowed from Bill, K4CIA, worked really well with my KAZ terminated RX
loop
for the low bands. It was connected to the receive antenna port on my
FT-1000MP, so I wasn't blowing FETs!
My electronic design career began before the end of the vacuum-tube era,
and
I used the 6DJ8 commercially in some VHF monitor receivers, as a cascode
RF
stage in the front-end.
73,
Charlie, K4OTV
-----Original Message-----
From: Andy Ikin [mailto:andrew.ikin@btopenworld.com]
Sent: Sunday, August 25, 2013 5:16 PM
To: Charlie Cunningham
Cc: Topband Reflector
Subject: Re: Topband: Anyone have a boat load of J-310s?
Thirty years ago I used 6DJ8 (E88CC) to solve a third order IMD problem
with
tuned loop that was using J310s.
The IMD was caused by Radio Free Europe on 13m.
73
Andrew
----- Original Message -----
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
To: "'Andy Ikin'" <andrew.ikin@btopenworld.com>; "'Topband Reflector'"
<topband@contesting.com>
Sent: Sunday, August 25, 2013 9:14 PM
Subject: Re: Topband: Anyone have a boat load of J-310s?
Of course, a 12AT7, or better, a 6DJ8, would be excellent preamps as
well,
and aren't so sensitive to transients etc. :-) (Showing my age, I
guess!)
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Andy
Ikin
Sent: Sunday, August 25, 2013 3:58 PM
To: Topband Reflector
Subject: Re: Topband: Anyone have a boat load of J-310s?
As far as am aware On-Semi still make the TO-92 J310. Fairchild ceased
production about 2 years back. I did a last time buy from Mouser for
several
thousand J310 and the much more linear J309.
73
Andrew Ikin G8LUG
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