High band vhf antenna on tractor

[chris4000]

Been trying to mount an antenna on my tractor on 165mhz going through a repeater,it’s fine on a mag mount but if I put it on a short bracket the swr goes into the red,it’s as if the bracket is acting as an antenna as well,

 

[Derek67]

Is there a flashing beacon anywhere near the short bracket?

 

[Stock]

Can you not adjust the aerial length to calibrate the SWR

 

[Bobthebuilder]

or not getting a good earth

 

[Mursal]

Jump lead on the bracket to a good earth, or better still the negative on the battery, just to test mind.

 

[chris4000]

Thanks stock for the video,I have cut and measured antenna several times tried it on a bracket by flashing beacon,put it on a mirror mount,got a good earth and cable.might need to shorten bracket as it could be acting as an antenna itself.