On Wednesday, November 5, 2014 12:33:48 PM UTC-6, John S wrote:


Can you tell us how big would it be? And what about the coil dimensions,
losses? Can you do an EZNEC model so those of us who have the simulator
can look at all the parameters/arguments?

It can be any size one wants. The bigger the better of course..
And all the other parameters can be adjusted also.. You use what
you can get away with to fit the room you have.
I don't recall having any mobile whips modeled, but it's hard to
say as all the older designs I did are on older unused hard drives
and I don't have ready access to them. I had to re-download quite
a few programs due to that reason.. I change drives quite often.
I just added two more 2 TB drives about a month ago.. I have several
TB these days.

All of Reg's old software can still be downloaded.
http://zerobeat.net/G4FGQ/page3.html#S301%22
Vertload was one I used a lot for playing "what if" when designing
mobile whips and other short verticals, and the info can easily
be used for small dipoles. There are others programs that can be
handy also.

It's been a long time since I used it, but I believe vertload
can be used to locate the best location on the whip to place
the loading coil. In general, you want it as far out to the ends
as possible for the best current distribution, but there is a
point where coil losses start to outweigh the improved current
distribution. So in the real world, the best location is usually
appx 3/4 the way out from the feedpoint, plus or minus.

And the use of capacity hats further improve current distribution,
and slightly reduce the number of turns needed for the loading
coil. A short dipole is never going to be quite as good as a full
size version, but with proper design you can come up with quite a
respectable antenna given the dinky size.



John (who was KD5YI but will be N1JLS in a few weeks due to vanity)

Hummm.. You now in 1 land, or you just grabbing an old call?
My current call is a vanity call, which I think I've had since '96.
I was WD5CJL in a past life.. I got that call in 77 when I was 20.

I actually got into ham radio when I was in the eighth grade, learned
the code, and even built a 6v6 transmitter from junk parts.
But then I got lazy and kind of got out of it a while, and didn't
actually get a ticket. Later on I got back into it, and got a ticket about
six years later. I used my first 6v6 transmitter when I was a novice in 77.
I was a SWL for a good while before I got into ham radio.
I worked a lot of CW back in the old days. I got up to nearly 60 wpm
at one point. But due to lack of activity the past several years, I can't
do near that now.