Homebrew 6T9 One Tube Transmitter
When studying for my Novice License, I began researching amateur radio equipment options. I checked out a copy of the ARRL 1973 Handbook from the local library and took interest in the transmitter beginning on page 169. The title of the transmitter was "A 10-Watt One Tube Transmitter". You can also find the same transmitter in the March 1971 QST magazine beginning on page 25. I took interest in the article because in my junk box I had a 6T9 vacuum tube along with other useful components for the project. The 6T9 tube is a compactron tube with a triode and pentode section. This transmitter uses the 6T9s triode for the oscillator and the pentode for the power amplifier. Well after I passed my Novice test I decided to purchase the Heathkit HW-16 and HG-10B VFO. I put the 6T9 back into the junk box that I still have today.
Fast forward to 2018, I decided to build the 6T9 transmitter for the 2019 ARRL SKN. It is powered by a Heathkit IP-32 I purchased from EBay. The IP-32 delivers 285 volts to the plate of the 6T9 vacuum tube, and the transmitter puts out a little over 5 watts output. Most of the capacitors, resistors, and chokes were from HamCom. The HamCom goldmine consisted of cardboard storage bins full of miscellaneous parts and were priced per box. I grabbed several boxes along with other hams. Here are several pictures of the project:
The above picture is after drilling, hole punching, and filing a 4 X 6 aluminum chassis.
The pictures above depict the chassis installing with the variable capacitors, tube sockets, a BNC connector, a phone plug, and a 4 pin male cinch plug for power.
Here are a few pictures showing the electronic components being installed under the chassis. During the smoke testing and adjusting phase, the two white wires were used for a 40M crystal, the yellow wire for the key, and two red wires for a 100mA meter.
The above picture shows me adding and removing wire from the tank coil to get it to resonate on 40 meters.
Here are a few pictures showing the rear and sides of the finished project.
Here is a front view of the finished project. The front panel was cut from a Walmart plastic clipboard The crystal I am using was the original crystal that came with my HW-16. The crystal is 7.110Mhz.