2015 Ram pickup truck 3500 diesel with quad band HV7A Diamond antenna

This antenna is mounted on my back rack light bar behind the cab on the drivers side of truck. On 2 meters my swr is 1.5 with the frequency set at 144.5 Mhz. Swr is 2.0 at 148 Mhz. This is the best I can get here. On the 6 meters band while set at 50.150 the swr is 2.0. While set at 54.000 mhz swr is 1.5, best I can get. On 10 meters while set at 28.000 mhz the swr is 5.0. On 29.700 the swr is 5.0. Would this be a ground issue or what else would it be ?? I have not added in any ground straps yet. Thought I would run it by all the experts out there on this subject. From the newbie HAM
KC1XJI. Thanks Roger

 

What kind of antenna?

 

Is it behind & below the cab, or above it?

 

your 'back rack light bar'..., is it mounted atop the plastic bedside caps?... don't forget the two parts of an antenna.

 

It is mounted almost flush with the side of the truck drivers side, just behind the cab. Only about 6 inches of the antenna is below cab height.

Diamond HV7A Quad band

 

Yes it is. But it is showing it's grounded

 

Diamond HV7A quad band

 

That 6" may be part of your problem and being lower and adjacent to the rack.

If at all possible, I would relocate the antenna to the center of the rack where I have annotated the red arrow on your photo, and try again.

 

Thank you N5AVF that makes sense. I will try to relocate it. I may have enough spare coax also. Roger KC1XJI