Yuri Blanarovich wrote:
1. Placement of the loading coil can drastically affect that. (Base loaded
vs.
Top Hat loaded)

BTW, Yuri, you and others may not be aware that my junk box top-loaded
mobile antenna equaled the best-of-the-best in one of the antenna
shoot-outs. The loading coil was just some cheap 1.75" dia coil stock
from my junk box. It wasn't anything like a bugcatcher and it cost
virtually nothing.


This is what W9UCW measurerd, that Q of the coil did not contribute
significantly to performance. If wire is reasonable gauge to carry the current
to minimize the ohmic loses, then it was very close with that super-duper Hi-Q
coil.

The bottom section was a 108" conductor curving toward the coil which was
***HORIZONTAL***. Yes, the coil was horizontal as was the top hat to which
it was attached. If I had known it was going to do that well, I could have
won by making the top hat a little bigger. Here is an ASCII diagram of that
antenna:
loading coil
- ////////////--Capacitive top hat
/
/
/
/
| Pickup
|
|
|
|
FP
--------GND------------------------------------------------------
So I discovered by accident what is being discussed now. Seems obvious that
the coil could be shorted and the top hat disconnected for higher
frequencies.
--
73, Cecil http://www.qsl.net/w5dxp



That is close to my "secret" K3BU 160m antenna that runs circles around the
"classic" whip. I used 80m regular Hustler coil. From the point where set screw
tightens the whip I run about 13 ft of wire, top loading to small mast on the
front bumper. By sliding that end up and down I managed to tune the antenna
within the bottom end of 160. It also gave me some horizontal component for the
NVIS.
The net result was that even with "lousy" Hustler 80m coil, I managed to
increase the high current carrying portion of radiator, coil didn't have to be
that large, top loading wire also served as a guy. I didn't use real hat, just
wire. Mast is mounted on the fender of 72 Buick LeSabre.
The flat earth society will argue that it can be only 0.1 dB improvement, but I
saw on average about 7 S-units boost. K5NA once travelled with regular 160m
mobile during the contest, didn't make single QSO. With my ugly thing I worked
stations from W6 through South America to Eu.
Another egg in the face Richard and his ridiculing.

73 Yuri