That wave you speak of is more for sending than rec....think of a bucket...if the wave is off during sending it become overflow and is wasted..To a degree some of the transmit signal gets shot back into the radio and eventually kills the finals of the radio..Dont hold me to this but it was how a cb fixer dude explained it to me..reception only would be helped if you run a ground wire from the ant to the chassie..again im not a 100% sure on that but it certainly belps with my cb in my rig..
With CB radios what you describe with part of the signal coming back into the radio is what we call reflection and can be damaging, different things cause reflection for my work applications one of the biggest things we look at are rust, secure connections, non-magnetic hardware, and moving metal (funny huh). With a receive antenna like your standard AM/FM car antenna there is no transmit and no power running through the antenna and really no need to ground it that I can figure, although we do use grounding straps on ours at work. With transmit antennas the length of the antenna determines your transmit frequency range, the coupler and/or transmitter/transceiver electronically shortens or lengthens the antenna for the desired frequency. Now for receive antennas this is where I get a little thrown off, I work with antennas but I primarily deal with Satellite Antennas, the higher up a receive antenna is the better reception you're going to receive, for ground and LOS antennas. Different frequency spectrums and different antennas propagate (fancy word for send pretty much) waves differently, in my line of work HF is a ground wave and pretty much follows the curvature of the earth and will go up and over mountains. VHF is normally referred to as line of sight basically the 2 antennas have to see each other, although for actual use I know VHF isn't exactly line of sight (sorry we are entering territory I'm a little fuzzy on) when we put it into a power assist. Now FM radio operates between 88 MHZ and 108 MHZ which is right inside the VHF range(30-300MHZ). So based on my understanding cutting your antenna should cause you to lose some range, for my work purposes we normally say approximately 45 miles with PA, which like I said early depends on the height of the two antennas (which is probably why radio towers are freaking huge). Unfortunately I couldn't even begin to estimate what their maximum range would be and it would vary from vehicle to vehicle based on height. I think honestly I have more questions than answers, AM runs on a much lower frequency in the MF range that I have no working experience with but I believe it works similar to HF, I've personally picked up AM radio stations thousands and thousands of miles away in my car granted it wasn't very clear but it was there. But this leads me to a question, those of you with Satellite radio do you have a separate antenna for the Satellite radio or is it all suppose to be built in?
