Fw: De-tunning or what?

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Original poster: "Charles Hobson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <charles.a.hobson-at-btinternet-dot-com>


Hi Peter,

Thanks to you and others for some most interesting responses. There is
enough to keep me out of mischief for a while.

A couple of comments on your response to my detunning? problem


> Original poster: "Peter Lawrence by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>
>
> Chuck,
>       this is the sort of behavior I get with a spark gaps that don't have
> enough gaps, in other words 6-segment multi gap would do this but
12-segment
> multi gap might not. I suspect it has to do with gap electrode heating. If
> your gap spacing is adjustable, then put your stand-by unit in series with
> your first one, and halve all the gap spacings, then see what happens.

I've had several other responses commenting that  possibility.  I don't
understand the mechanism  on how heated spark gaps cause my problem.Yes, my
gaps are adjustable. I may try the two gaps in series. I am using 18mm
diameter copper tubing with alternate tubes at right angles. This apparently
would concentrate the heat right at the gaps. See
www.charles.a.hobson.btinternet.co.uk/chuck I am putting together another
gap using something similar to Terry's multi-gap which I will try out
shortly also.
> I've had this problem with brass and stainless steel, but not with
tungsten-
> carbide. Tungsten carbide is the opposite that until the electrodes heat
up
> they work best with a wide spacing and then as they heat up the gap has to
> be closed down.
>
> (YMMV, I've never used more than a 9-30 NST)
>
> The other possiblity is if you use ceramic caps in your primary they can
> heat up and de-tune. Polypropylene caps don't seem to have this problem.

I am using polypropylene cap. Other coilers are using the same type as mine
and don't seem to have such problems.
>
> -Peter Lawrence.

Thanks again. Chuck