On Mon, 28 May 2007 11:10:04 GMT, "Nick" wrotF:

I am wanting to build 1/2 wave end fed ground plane independent aerials for
2M and 70cms for use on
touring motorcycles for bike to bike comms.

At the moment we are using 5W hand helds with the helicals, but I was
wanting to experiment with half waves
better sited, to increase the max range possible between the bikes -
groundplanes are not practical. On 70cms
the aerials will be physically smaller but not sure how the range might be
affected / reduced

Has anyone suggestions on band to use and/or designs for suitable aerials,
or a link to a site with details ?

Thanks,

Nick

There are a number of commercial dual band ground plane independent
antennas available. Many of the Comet antennas are supposed to be
ground plane independent.
http://www.cometantenna.com/FAQs.php?ID=1

If you want to build your own, a J-Pole design could probably be
adapted. One of the guys I know uses a home build copy of the Arrow
dual band J-pole on his Jeep wagon.
http://www.arrowantennas.com/inst/ijpole.html

Mike kc9doa