-- 
Have Fun,

Brooke Clarke
https://www.PRC68.com
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.

What I discovered over the years was a lot of people already walked the
path I was currently following. No where did this become more self
evident than the construction of? helical wound inductors.

The general rules mentioned in many writings, both amateur and profes-
sional state that to obtain highest possible Q the coil should:

(1) present a width to height ratio of 1. In other words if the coil is going
to be 1 inch high, then use a former slightly less than 1 inch so the the
center to center space of the wire conductor helix? is 1.

(2) Use as large as practical wire diameter. If you look at skin effect and
quantify the resulting resistance at RF, you will marvel that you can obtain
Q's nearly as high as being achieved.

(3) Space the turns of the inductor no less than one wire diameter from
each other across the former's surface.

(4) Use a single layer on the former. Just one turn overlapping the beginning
of the coil can shed nearly 80% of the Q and matters only become worse
with more overlapping turns.

(5) Know the source of your wire. Not all copper wire is high grade 99%
copper.

(6) If you are going for that last 2% of Q, then bite the bullet and either have
the wire silver plated or bump the conductor up to the next larger diameter
wire size.

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(6) If you are going for that last 2% of Q, then bite the bullet and either have
the wire silver plated or bump the conductor up to the next larger diameter
wire size.

You may want to try Cool-Amp, but it's awfully expensive.

When I was spending a lot of time winding high Q coils and testing them on the Boontoon 160 it was clear than anything closer than maybe a few coil diameters would effect the readings.?

Generally, mil-spec silver plating starts at 0.0005" thickness, however a number of shops
now plate upwards of 0.015" if ordered. If you do silver plate you want to be sure to use
silver's characteristics for skin depth as it is a few microns more shallow than copper,
about 3%.

One positive for using silver plate is, that electrodeposited Class T silver plate has
additives which dramatically inhibit tarnishing. That is useful in many corner cases,
especially if foods cooked in the home have fair amount of sulfur in them. Included
food are eggs and onions as well as a myriad of other pungent vegetables when
cooked.