All,

Reg's counterpoise program predicts the effective ground of a centerloaded
vertical on 75 meters can be improved by a tuned relatively short counterpoise
system. This is dependent on a large, high Q, low loss tuning coil.

After some playing with the numbers a starting point for the design of such a
coil is 200 mm diameter, 200 mm long, with 4 gage wire, and a pitch of about .7.
This is obviously quite large.

My questions a

1. Where is a good tutorial for large coils?

2. Are there coil forms for such coils?

3. What would the impact of a square or octagon be versus round?

4. How critical is spacing toward a high Q?

Thanks,

Dan - kb0qil

dansawyeror wrote:
Reg's counterpoise program predicts the effective ground of a
centerloaded vertical on 75 meters can be improved by a tuned relatively
short counterpoise system. This is dependent on a large, high Q, low
loss tuning coil.

Are these elevated radials? How elevated? High-Q coils
in ground-level radials would probably be a waste of
time and effort.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil,

They are elevated, based on Reg's program. It predicts that a relatively large,
diameter about equal to length, 2 gage wire, high Q coil feeding a 2 meter
radial about .5 meters elevated produces a resistance of just over 2 Ohms. This
is at 3970 kc.

I have not tried this with another model, I seem to be unable to create coil
descriptors to feed nec.

The fundamental construction questions relate to 'accuracy'. What would the
effect be on Q be of a flat sides? What would the effect be if the wire (I plan
to use 1/4 inch copper tube) had small 'ripples' in the wind.

Thanks - Dan



Cecil Moore wrote:
dansawyeror wrote:

Reg's counterpoise program predicts the effective ground of a
centerloaded vertical on 75 meters can be improved by a tuned
relatively short counterpoise system. This is dependent on a large,
high Q, low loss tuning coil.


Are these elevated radials? How elevated? High-Q coils
in ground-level radials would probably be a waste of
time and effort.

On Sat, 11 Feb 2006 08:16:41 -0800, dansawyeror
wrote:

All,

Reg's counterpoise program predicts the effective ground of a centerloaded
vertical on 75 meters can be improved by a tuned relatively short counterpoise
system. This is dependent on a large, high Q, low loss tuning coil.

After some playing with the numbers a starting point for the design of such a
coil is 200 mm diameter, 200 mm long, with 4 gage wire, and a pitch of about .7.
This is obviously quite large.

My questions a

1. Where is a good tutorial for large coils?

http://www.seed-solutions.com/gregor...on/HiQCoil.htm

Especially his reference No. 5.

Not specifically about inductor design, but might be of interest, are
some modeling experiments I did at:

www.k6mhe.com/n7ws

Nos. 1, 2 and 3.

Also see No. 14 if you think silver plating will help. (It won't).


2. Are there coil forms for such coils?

3. What would the impact of a square or octagon be versus round?

4. How critical is spacing toward a high Q?

Thanks,

Dan - kb0qil

Wes,

Thank you. That is exactly what I was looking for. My question is: How is the
coil wound? The author speaks about threading. Do you have a reference about how
to wind one?

Thanks - Dan

Wes Stewart wrote:
On Sat, 11 Feb 2006 08:16:41 -0800, dansawyeror
wrote:


All,

Reg's counterpoise program predicts the effective ground of a centerloaded
vertical on 75 meters can be improved by a tuned relatively short counterpoise
system. This is dependent on a large, high Q, low loss tuning coil.

After some playing with the numbers a starting point for the design of such a
coil is 200 mm diameter, 200 mm long, with 4 gage wire, and a pitch of about .7.
This is obviously quite large.

My questions a

1. Where is a good tutorial for large coils?


http://www.seed-solutions.com/gregor...on/HiQCoil.htm

Especially his reference No. 5.

Not specifically about inductor design, but might be of interest, are
some modeling experiments I did at:

www.k6mhe.com/n7ws

Nos. 1, 2 and 3.

Also see No. 14 if you think silver plating will help. (It won't).


2. Are there coil forms for such coils?

3. What would the impact of a square or octagon be versus round?

4. How critical is spacing toward a high Q?

Thanks,

Dan - kb0qil