[ARC5] ARC-5 antenna match

[Kenneth G. Gordon]

On 30 Jul 2013 at 10:42, Neil wrote:

> Well, not to nitpick but it's not quite the same.

No.

> Ken feeds ARC-5 output direct to its tap, you feed it via a 200 pF
> capacitor. This capacitor adds another element into the tuning and
> must be factored into the physical layout.

Yes. Exactly.

> You both have the same principle, but if his method works as well as
> he says, I'd prefer its simplicity.

It always worked very well for me.

Another method I have used in order to reduce the number of variables was 
to couple a 2 or 3 turn external link to the "cold" end of the coil and connect 
that link to the coax.

That reduced the number of taps I had to mess with from two to one.

This would only be valuable if you are always using a ~50 ohm load, though.

In my simplest version, I used the roller of the ARC-5 roller-inductor as the 
tapping-connection, and the same link as above to connect to the coax.

Either version matched a pretty wide range of impedances, although the 
simpler versions were only good for use on any one band.

I used the first one I built for several years until I lost it during a move.

What I had in my mind was an RF-capable Variac. If you draw it out, it looks 
exactly like one, except that there is a variable capacitor across the coil.

Ken W7EKB