The
Home-Brew Tube Receiver at VK2BA
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This
elaborate project was largely the result of a need for a purpose built
receiver to handle AM transmissions. I admit that I almost lost interest
in the project and probably would have done if it wasn't for the
components generously provided by interested hams, and mailed to me half
way around the world by Smitty, KD4AF. I felt that if people were
showing confidence in my ability to construct such an elaborate item by
supplying knobs, switches, capacitors and the S meter, then I should do
my part in completing it. There is still some cosmetic work to be
completed and that will be done in due course. In particular, I intend
to have some little engraved labels made to identify the panel
controls.
I can hear
some people asking why a tube receiver in the year 2001? I can only
quote KD4AF who sometimes quotes Louis Armstrong. Louis, when asked why
he liked Jazz, answered: "If you have to ask, you would never understand
the answer."
A Brief Description
of the Receiver
* Tubes: 22
* Bands: 7
(3.5 to 4.5, 7 to 8, 9 to 10, 14 to 15, 21 to 22, 28 to 29 and 29 to 30
MHz)
* Dual or
triple conversion (depending on the selectivity selected)
* Wide band
AM, Narrow band AM and SSB
* Push Pull
audio output (2x 12A6)
* Tone
controls: Bass & Treble - boost & cut
* Crystal
calibrator providing 100KHz and 10KHz divisions
* Dial home
made based around a 30:1 reduction gearbox from an old Yaesu FTDX400
* I have
also gone to extreme lengths to stabilise the VFO by running it on a
stabilised 12.6V DC filament supply. The VFO and two buffer amplifier
heaters are never turned off.
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