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Friday, November 11, 2016

super cheap Lmatch complete!

with a tad of homemade engineering,Microsucks paint and an old first aid box I built a simple backup tuner. Not the best in the world but it tunes up everything just fine. 

Parts list
metal first aid box-----free
old 200 Pf variable------free 
old crappy PL connectors-----free
Silver coax shield from old really high quality coax----free
inductor-----20ish uH-----homemade from copper house wire------free
crapload of 1000 volt ceramic caps for 6 position switch-----$5
some switches-----$4
Learning stuff------Free 

The schematic below shows the reverse switch in place which allows you to tune high and low Z. So you can pretty much cover the entire smith chart if you have enough capacitance on this thing.
So give the poor bastard 3500 or so pF so you can really make it bang. mine has 2400ish and it's not quite enough.The face is made on microsucks paint and printed on a piece of paper then coated with polyurethane spray paint. You can use a thicker print surface like  magnetic print paper or whatever and really make it nicer. But I'm cheap and poor so it was a nogo for me. The project cost me maybe 15 or 20 bucks to make so it was fun as well as cheap.

                              Half assed schematic!! 

                           Finished Shitty L match Version .003
                                      with all seeing eye mod

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