"Bob Bob" wrote in message
...
Sorry for barging in again Nick! This isn't directly related to your Q.

I guess that you are using the system for general comms as well a
safety. One of the features I think is available using DCS on some
radios is the ability to poll for the other station. The equivalent of
"are you there?" without actually speaking into the microphone.

This feature would be very helpful for safety issues as you at least
know if the other station is in range or not. Cresting a hill at the
same time for example may give you range you wouldn't normally consider
as viable.

This may even be able to be automated to the extent where you can poll
for the other station every minute or so.

I have never done this myself so don't know the full details. There was
a nearby station though that used it regularly to poll his local
interest group. My horrible old VHF/UHF gear is nowhere near as new
fangled as that! grin

Bob


Yes, we have that feature - using FT-60s at the moment but if we lose range,
we immediately go to high power and
if that doesn't work, stop at the first opportunity and use the cellphones
to report where we are ( each has GPS )
Never had to use it yet though but that's the back-up plan
Nick

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