Re: LF: Better picture of the 807 based 500kHz TX

[Dimitrios Tsifakis <dtsifakis@gmail.com>]

Hi Stefan,

I am also not part of the tube generation (born in the seventies) but
I am fascinated by them! While a class-E PA is a very sensible and
efficient PA, tubes (or valves) have a different kind of appeal to me.
My 40 m transmitter is based on more than 50% recycled material which
dates back to the 40s and 50s. The knobs and panel meters are from an
old 30 kW AWA ISB transmitter. The 807 I am currently using (not the
one in the photos) is an old soviet one, the 6CL6 comes from an old
TV, the sockets from an old amateur boat anchor etc...

Anyway, I do plan to use a class-E PA for my QRSS transmissions on LF/MF ;-)

73, Dimitris


2012/12/19 Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>:
> Hi Dimitris,
>
> Tubes for PAs is not my world (generation) but the topic is most interesting
> and the webpage too.
>
> Good luck and i hope to see some traces from you some time, at constructive
> QSB :-)
>
> 73, Stefan/DK7FC
>
> Am 18.12.2012 22:07, schrieb Dimitrios Tsifakis:
>
>> By the way, here is my current 40 m 807 transmitter.This was the first
>> attempt at building a valve TX.
>>
>> people.physics.anu.edu.au/~dxt103/valves/807/
>>
>> I will use the same type of chassis for the 472 kc version but I will
>> use an old 450-0-450 (50 mA), transformer which also has a 225-0-225
>> and 6.3 windings, for a more compact result. My hope is that I can
>> draw a bit more than 50 mA without overheating the transformer and is
>> based on the fact that CW is not 100% duty cycle and also I am not
>> using the other windings to their maximum current ratings.
>>
>> 73, Dimitris VK1SV
>>
>
>