Matchbox

I have talked about matchboxes before (yesterday as well), but since I just finished building my very own (or rebuilding it, rather - I just replaced the inductance), I'll talk about them a little more. To the left you see the new matchbox in all it's gory glory. Two vacuum capacitors (expensive), an air-core coil (that's the red piece of wire in the middle), that's all there is. Oh and its a π - matching network, if anyone is interested. Its called π - matching network, because it sort of looks like a π, if you squint and are bored and are looking for a cool name for your new network.

For contrast, there is a picture of a commercial antenna tuner below. In fact, it is the one I killed the other day. What happened is that the inductance burned, because it is much more feeble and wimpy than my macho inductance on the left. Also, the capacitors of the commercial version are air-core capacitors, much less cool (or should I say much more uncool? Neither sounds exactly english, but since I am residing in Suisse-romande, I get to ignore stuff like this.) than my hypercool vacuum capacitors - much cheaper as well, because mine cost about 1000 SFR apiece. the tuner is a T-matching network (guess why), which is not ideal for plasma matching, but works anyway.



Even belower you can see a closeup of the damage of the Coil That Lost.

I was also going to write a bit about how matching networks work, but ended boring myself and stopped - for which I hope you will all be grateful. Anyway, since the calculations for the coil I used were pretty simple (I took a piece of wire, wound it a couple of times until it cried, stuck it into the box and got lucky), there is no need to dig up all the theory.