Topband: Anyone have a boat load of J-310s?

[Andy Ikin]

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 at nc.rr.com>
To: "'Andy Ikin'" <andrew.ikin at btopenworld.com>
Cc: "'Topband Reflector'" <topband at 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 at 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 at nc.rr.com>
> To: "'Andy Ikin'" <andrew.ikin at btopenworld.com>; "'Topband Reflector'"
> <topband at 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 at 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
>>
>>
>> _________________
>> Topband Reflector
>>
>> _________________
>> Topband Reflector
>>
>
>
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> Topband Reflector
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