Frank,

Good morning. Let me start at the beginning. I have a loaded vertical on 75
meters. The combination of the antenna and ground measure about 40 Ohms at the
antenna. The models all show such an antenna over a perfect ground should have a
radiation resistance of between 3 and 4 Ohms. That says the antenna system is
less the 10% efficient.

This then is a journey to reduce ground resistance. Attempts to add radials and
wire mesh to the ground have had very little if no effect. This leads to Reg's
c_poise model. It predicts a coil in the range of 60 uH to 90 uH tuned to a 2
meter by 18 mm 'wire' will have a total resistance in the 2 to 4 Ohms range.

Together this should result is a 8 Ohm system. The ratio can be directly
inferred as an performance improvement of 5 to 1 or 7 db. This is worth some
effort.

To answer your question the first step will be one coil and one radial. The
objective is the get the antenna system close to 10 Ohms. From there I will
experiment with adding radials and coils. I am not sure what to expect.

Thanks - Dan





Frank wrote:
Not sure I understand what is going on Dan. Are you planning on loading
each radial element?

Frank


"dansawyeror" wrote in message
...

These results were from Reg's c_poise program. The band is 75 meters and
the coils were about 70 uH. The coils were a relatively large diameter, on
the order of a meter. The wire lengths were about 20 meters. By varying
the length the coil, the coil wire may be varies from 1mm to 12mm.

Richard Clark wrote:

On Sat, 18 Feb 2006 08:20:38 -0800, dansawyeror
wrote:



The devil is in the details. Modeling shows large coils with 1 mm wire
have a Q in the range of a few hundred. On the other hand a coil with 12
mm tubing has a Q of about 2000. The R of the 1 mm coil is about 6 Ohms
while the 12 mm coil is on the order of 1 Ohm.

Given these model results it says there is a significant difference
between 1 mm and 12 mm coils.


Hi Dan,

In the details, indeed. What is the LENGTH of wire in this 6 Ohm
resistor? What is the LENGTH
of wire in this 1 Ohm resistor? How many turns are in these "large
coils?" What is their diameter? What is their solenoid length?

Without these details, there is nothing said that is significant.

73's
Richard Clark, KB7QHC