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W4JBM's Tube Projects

CAUTION! This project involves exposed high-voltages. These voltages can be dangerous or even lethal. I don't suggest you attempt to match my construction--there are safer ways to build this. Dangerous voltages are exposed at several points in this project. And only those with adequate training, equipment, facilities and experience should attempt to construction of this type of equipment. You can kill yourself! This information is believed to be accurate, but please verify and understand what you are doing before undertaking this type of effort.

I've been messing around with tubes for several months now and had a blast. I've tried several types of transmitters with mixed success. My first project was a single tube (dual triode) transmitter. For a couple of reasons, I wasn't happy with the results.

My latest project is the NoGa Twin-Tube transmitter based on a kit by Mike Branca, W3IRZ. I still have some work to do before this one is finished, but several people have asked for pictures of transmitters, so here it is (above).

The transmitter was built on a loaf pan (two for around $3.00 at Walmart). The tubes and the tank components are on the top. The front has an input for the key. On the back is the power supply inputs, the antenna output, and an input for either a crystal or a VFO.

In the picture, my power supply is to the right of the transmitter. This puts out up to around 180 volts DC, regulated (to remove hum) and 12.6 volts AC (center tapped) for the heaters. In the foreground, to the right of the key, is a small crystal test oscillator I used to make sure the transmitter would work with a VFO input as well as with a crystal.

I like the way the loaf pan looks, so I'll probably build a matching VFO/TR-switch and a receiver along the same lines.

I'll put more details up on my web pages when I have more time...

 


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