Tom wrote:

Hello all ,

I would like to install a VHF-UHF antenna on my motorcycle . It's a Suzuki
GSX750 . I did some tests with a Diamond NR-770H and it works well . The
only problem is that the antenna is to big for such a bike .
Afterwards i did a test with a Diamond NR-77 . The antenna is about 43 cm
and that's about the size i would like to use .
The problem i have with this antenna is the swr , it's to high .

Anyone an idea how i can solve this problem ?

Many thanks .


You may not be getting a proper counter-poise to the antenna system.

I would check grounding on the antenna and make certain the antenna
mount is in good solid contact with the metal frame of the bike.

You mentioned the larger antenna worked well. Does that mean the SWR
was good or it just performed adequately?

Which band is having the SWR problems?

What type of mount does the Diamond use? I am very partial to the NMO
type antenna mount. I know there are some antennas that use an SO239
type mount which is just a "UHF" connector on the end of a piece of
coax. These are not that well suited for 70cm operation although you do
see them quite a bit.

Also, how much power are you going to be putting into the antenna? I
would be concerned about RF exposure if its very much.

Andy
WD4KDN