On Wednesday, November 5, 2014 1:46:18 PM UTC-6, wrote:
wrote:
On Wednesday, November 5, 2014 1:01:02 PM UTC-6,
I would think a dipole would be a bad candidate for a "short" antenna
as you need to get the matching stuff close to the antenna to avoid
I^2R losses.
I'd probably use small matching coils at the feed point, about the
same as a mobile antenna.
There is a lot of stuff out there that says the best place to put
a loading coil is somewhere between 1/2 and 3/4 of the way up.
My usual 11 ft 80-10m mobile antenna in the driving mode is exactly
center loaded. The coil bottom is at the 5 ft point, and there is
a 5 ft "stinger whip" above it. The coil itself is about a foot long
and has taps for the various bands. I use shorter stinger whips for
the higher bands.
But in the parked mode, I have a solid three foot mast that I screw
onto the base of the main whip, and the coil is at the 8ft level.
It makes quite a difference in efficiency. I don't use a hat on my
mobile antennas because I think they are ugly, and catch too much wind.
I also have a screwdriver antenna I got free, but it's inferior to my
homemade "plastic bugcatchers", and I've never used it. It sits in the
garage and collects dust.
I've used a 706mk2g as the mobile rig since about 2001 or so. But I
recently picked up a FT-100 which could be used also. I also have the
matching auto tuner for that rig, but not sure if I would ever use it.
I don't need it for my usual mobile whips as they are matched with the
"dollar special" matching coils.
It should be fairly easy to model to see where it would be for
various total lengths.
Yep.. I think vertload will do it if I'm remembering the right program.
In the real world, I try to avoid short antennas.. 
It's only a last resort due to lack of room. I rarely actually use one.
Me too for the most part.
I've never felt a need to go mobile any lower than 10M though I have
put some thought into shortning 160M antennas.
I've had a 80-10 mobile antenna for many years. When parked, I've
used it on 160m by clipping on a longer wire above the coil.
Both of my trucks have antenna ball mounts. But the Toyota car I
drive does not have anything, because I'm chicken to booger up the
pristine body with holes and such.. :/
One concept I started playing with but never finished was the folded
monopole, i.e. half of a folded dipole, but with more than one "folded"
element in an attempt to get the radiation resistance up.
I've never tried anything like that.