Neil's Amazing Tube Transmitter came to mind when the furnace blower switched off at the same moment I was checking on my two AM transmitters. Outdoor temperature this morning is 30-degrees. Right at that same moment the light bulb I installed yesterday made a "pop" and burned out. It was one of the last incandescent bulbs in the collection, and was valued for its heat on a cool day.
The two AM transmitters on the air are both solid-state and produce little heat. Heat would be one benefit of having tube transmitters.
However, if I had a tube transmitter I'd want to rig it just like a higher-powered one and install a blower-fan.
Blower fans are distinquished by being contained pneumatically in a ducted housing to force air across the tubes to keep them from melting down into a pool of molten metal and glass.
I'm guessing that even a small transmitter like Neil's might benefit just slightly by adding a blower which might possibly extend tube life by a day or a week. That heat would flow out of an exhaust port on the side of the transmitter like a micro-furnace.
The "Hand Warmer".
I've got a pile of those tube blowers in a back corner at the full power transmitter site, complete with spare tubes for the unused Collins Transmitter.
I'd like to run the two finals from a GE 250 watt FM I had on a display board but the filaments draw like 15 amps each. Kept the tubes when I scrapped the transmitter.
Should be some heat there!
That's a nice transmitter, how is it working these days? You could build a vintage receiver to go with it!
Nice!
The positive comments are appreciated.
This was mostly built for geek eye candy and a small blower would further enhance this though I doubt it will extend tube life. These tubes are designed to lose heat by radiation (hence the dark plates)and convective cooling is not very efficient here. Actually, the worrisome heat in this unit comes from the power transformers which are running close to their ratings.
Regarding performance, the audio sounds good and the range is the same as I reported earlier, about 300 feet on a car radio. It is plenty strong inside my house and around the yard. One thing which I like compared to my base coil loaded outdoor antenna system is that if I move this or change something it is very easy to tune for a dip in plate current.
MRAM's comment about real power tubes is so true. I have a few here and it would be fun to display them lit but they require amps for the filament. Some folks mount them on wood stands and bottom light them with LEDs to fake it but that never looks as nice as the real fire inside.
Neil
Carl,
The mop handle was also called the Jesus Stick, jam it in there to force the relays to close lol and if it made an arching noise you'd yell JESUS!
Some engineers even claim their assistants had to change their pants, could be an urban legend...buuuut.. lol