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

[Bill Cromwell]

On 08/25/2013 06:31 PM, Andy Ikin wrote:
> 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
Hi Andrew,

When we build our own gear we do learn a lot. The first gear I built was 
a V-O-M in a cigar box. I was around about 13 and somebody gave me meter 
movement. Cigar boxes were free and so were junk televisions and radios. 
The ARRL handbook was over at the library. I didn't have a mode switch 
or a range switch but plugged resistors into an octal socket to make up 
each mode/range. I used it for almost two years before I got a *real* 
V-O-M. The real one was a little more accurate and a lot more convenient 
to use. But to this day I am familiar with how voltmeters work! That was 
about 50 years ago... I'm 66 now.

73,

Bill  KU8H