I have a Grant XL that I have installed in a 2013 Chevy Tahoe. Power is direct wired to the battery and I have done all of the normal tests to ensure the radio/antenna/coax/ground wire/mount are all where they need to be with respect to resistance and Ohm testing. I am still seeing super high SWR readings (3+) so my next step will be testing the radio to ensure nothing is wrong with it. Is there anyone in Louisville, KY or nearby that can ensure/test the radio is operating as it should? I'd be happy to pay for the test and would be more than willing to bring the radio to you. It is a radio that was given to me and I can only assume it was working when it was taken out of the previous vehicle.