KC9KEP - A work in progress

  Homebrew Radio Projects - Novice 80, 40, 15m Transmitter

Novice Transmitter
front panel
front panel
under the chassis
back view

This was an exciting project for me.
Not only was it fun to learn about how Ham transmitters work, but it was another great vacuum tube project.  Again, I'm blown away by the performance of such a humble transmitter.

This unit gave me the opportunity to try my newly acquired skill of sending Morse code.

As luck would have it, my first CQ transmission was answered by a ham in Graniteville VT, K1HTJ, a distance of about 1024 miles from my home!

Unreal!  This transmitter fundamentally uses one tube to oscillate and transmit and the tube is really a horizontal output tube for a TV set!

Since building my first version of the transmitter, I've redesign the front panel, moved the current meter to a more aesthetically pleasing location, and laser engraved it.

But before I get carried away, I need to do more QSO's (ham conversations on the air) and hone my craft.  Heck, I like morse code almost as much as vacuum tubes and I've only learned it a month prior to this writing!

Anyway, this design was fist featured in a December issue of QST magazine, and was printed in at least a couple years of the ARRL handbook.

I "discovered" the transmitter in an ARRL handbook that I picked up at a ham fest, sans cover, for a few bucks.

You never know what reading a book will lead you to doing :-)

The design features an 0D3 150V DC regulator and cathode bias resistor that help control "chirp".  A "pi" filter is featured in the xmitter output.  The set even includes a headphone "side-tone" monitor, (but it sounds a little buzzy to me.)

I had considered building a much older vintage unit, but I didn't want the FCC knocking at my door for operating a "spark transmitter"!

I works well with the antenna matcher.