Highland Ham wrote:
Michael Coslo wrote:
John Passaneau wrote:
I can't help with the coil, but the coax is 1/4 wave length at 20m.

I think the coil is around 1.5 inches in diameter, and has around
25 turns or so. It's used to fine tune the swr. In a not very elegant
looking method, you decrease th inductance by pulling the turns apart.
Te better the ground, the worse your coil will look.

It isn't terribly sensitive in the manner that the upper coils are, so
that 1.5 inch/25 turns description will probably get you in the ball
park.

I'll check mine (its an HF6V, but should be similar) tonight.
===========================
Tnx John ,Unknown and Mike for your response. I'll have a look at the
Butternut site and make a base coil.
Many moons ago I witnessed vastly improved performance of a Butternut
HF6V ,which had the base inductor and initially only 1 ground spike.
The antenna was situated in the middle of a lawn.
After covering the area around the antenna with chicken wire mesh
performance improved by 1 to 2 S-points Within 3 weeks the wire mesh
was no longer visible and the grass could be cut by moving a mower over
the wire mesh .
But with the HF9V I first try to set it up by the book (later in august
when I'll be back from a trip)

Tnx agn all

Frank GM0CSZ / KN6WH

PS : In the meantime I'll keep monitoring this NG for any additional
relevant info.
======================================
Butternut manufacturer ' Bencher' has now provided the following info :
QUOTE
Coil Q Base Matching - can be made out of 17 turns of 12 awg magnet wire
wound on a 1 1/4 inch (31.8 mm) form.

Coax 75 Ohm Matching Line - made from RG-11 75 ohm coax, 11 ft 4 inches
(345.4 cm) if solid dielectric, 13 ft 6 in (411.5 cm) if foam type.
UNQUOTE

I am happy with the above . This item can be closed.

Frank GM0CSZ / KN6WH