On May 13, 11:43 am, Michael Coslo wrote:
Highland Ham wrote:
Mike Coslo wrote:
I would suggest that No Spam might try an experiment, making a stub
as a first try. It's simple enough that if it doesn't work, there
isn't much effort wasted.
=====
Mike , Was that a single or treble stub (Pi shape) ?

It was a single stub. The situation was during a contest, so I had to
come up with something quick. I can only imagine something like a Pi
stub would have been all that much better.

- 73 de Mike N3LI -

But as I understand it, Mike, it was to kill something at least 4MHz
away from 14MHz. That doesn't take a very high Q. The OP was asking
about killing something 100kHz away, at 14MHz, and that's entirely
different.

I assume yours was a 1/4 wave stub on the freq you wanted to kill,
open on the free end (or else a 1/2 wave stub, shorted on the free
end). If it was RG-213-size coax, I'd expect the Q at 14MHz to be
about 100. I can do that at 14MHz in a coil about 1/3 inch in
diameter and 1/3 inch long.

Cheers,
Tom