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Rex,

Here's what those tubes were for...

Attached is the circuit of the 12AL8 I built as a potential kit for the 2017 BuildAthon.

It works but very little RF output.


Chuck, W5USJ (ex K2OFN)
ARCI 5422, SKCC 19956
EM22cv, Rains Co., Texas
--
Chuck, W5USJ

"LookMa" kit using space charge12K5? tube. ? 20 mW?? Could proly fit it into a tuna can with tube n crystal plugged into the top?



Curt KB5JO

Curt et All,

The article is on pages 20/21 of the May 2006 magazine.? I don't have that issue on hand but I'm a subscriber so probably can get it if anyone is interested.?

It's a pentode in a Pierce oscillator configuration. Space-charge tubes can be fun as the B+ is only 13.8 Vdc.? Down side: It takes about 3W of filament power to get 25 mW of RF power...

HamCall has back issues but you need a paid membership to get them.




?See the schematic... ;-)

For a little retro hollow state fun, there are several circuits around.? Like Curt sez, maybe there could be a Tuna Can kit in the future?


At 03:08 PM 5/27/2020, you wrote:

[Edited Message Follows]
"LookMa" kit using space charge12K5? tube. ? 20 mW?? Could proly fit it into a tuna can with tube n crystal plugged into the top?

Chuck, W5USJ (ex K2OFN)
ARCI 5422, SKCC 19956
EM22cv, Rains Co., Texas
--
Chuck, W5USJ

Here is picture of N5ESE Altoobs.? Of course it uses some conventional tubes at 150V B+ for 2W output

Curt KB5JO