"Cecil Moore" wrote in message
. ..
Bindy wrote:
Cecil Moore wrote:
Based on some calculations I did today, I am offering
an original rule of thumb (as far as I know). Regarding
a coax choke, when deciding how many turns of coax to put
on a 2 liter pop bottle at two turns per inch, one needs
to avoid the self-resonant frequency. So don't put more
turns on the choke than the number of meters in a wavelength,
e.g. no more than 20 turns on 20m, no more than 6 turns on
6m. Backup calculations will be published on my web page.

20 Turns is way too much for 20 through to 10.

I didn't say anything about "20 through to 10". Here's what
my rule of thumb says:

No more than 20 turns on 20m, no more than 10 turns on 10m,
and no more than 6 turns on 6m.
======================================
Cec,

Does all the above apply to the diameter of a pop bottle?

And what is the diameter over the plastic jacket of the coax?

The length of the coil will be N times the jacket diameter, assuming
the N turns are close-spaced.

Don't forget, mean coil diameter will be pop bottle diameter plus coax
jacket diameter. It does make a difference.
-----
Reg.