Quote:
Originally posted by copper017:
There are two types of grounds with a transmitter system. RF ground and electrical ground. An antenna can function without the mount being attached to ground because the RF siganl will inductively couple to the flat plane of metal (roof) beneath the antenna. Depends on antenna design. The SWR is the key to your success. If it goes up when a ground is attached then that is indicative of having a difference in ground potential between the electrical and RF ground. So if SWR's are better without the second ground attachment, go with it. This discussion goes round and round here. To qulaify myself, I have been an Extra Class amatuer operator for 16 years, hold a General Radio Operators License and a degree in EE. Take it for what it is worth and have fun.
Thanks for the information and confirmation of what I have been doing. I had a similar experience as the person who started the thread (although with a different antenna mount). I originally had the antenna bracket clamped to the lip of the hatch. I had a good SWR of between 1.2 and 1.1. The antenna was clearly grounded in this set up. When I moved the mounting location to the cross bar on roof rack (which I understand is *not* grounded as a result of at least the plastic/rubber connection between the cross-bar and main rail), I added about a one foot length or wire to ground the antenna to one of the hatch bolts. My SWR was up over 3. When I removed the ground wire, the SWR was back to between 1.2 and 1.1. I have run it without the ground wire for several weeks now with no ill effects.

k_enn