"Ken Bessler" wrote
For the record, I'm trying to understand some manufacturer's
claims that the antenna they sell, while smaller than a
1/4 wave whip on 10m, puts out a better signal.
Here are the rules:
1) The antenna is at least 25% shorter than a 1/4 w whip
2) The antenna is made with ordinary materials - no friggin gold.
3) The antenna is omni-directional & vertically polarised
4) The feedline is Flexi 4XL, aka CQ-102
5) The antenna is mounted dead center on the roof of a van.
6) The antenna's mount is non magnetic - I.E. There is a good
DC/RF ground at both the base of the antenna & the radio.
__________

A perfectly "omni" azimuth pattern is unlikely from a v-pol whip of any
length when mounted on the roof of a van, however ~ 2.15dBi lobes could
exist in some directions. The electrical environment around the van will
shape the pattern further.

This could be modeled in NEC to give some insight into the situation.

RF