David Macnaughton and his Fascinating World of Amateur Radio



Please Scroll (16 items)
























The Home-Brew Tube Receiver at VK2BA

Click image to view full size

The new 22 tube receiver at VK2BA

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.


Top view pf VK2BA 22 tube receiver


Rear view of VK2BA 22 tube Receiver


Under chassis view of 22 tube VK2BA receiver