I just bought a cobra 29 ltd to go into my 1988 Cadillac Elderado. I am using a cigarette lighter power source until I get more a more permanent power source. I am using a K30 antenna mounted in the center of the roof and a radioshak swr meter. My problem is that on channel 1 and 40 the swr in a little above 2, but only 1.1 on 20. I didn't think that swr could be that low on this kind of set-up and was wondering why the low point was at 20? What if anything should I be worried about?