Foundations of Amateur Radio Recently I had the opportunity to operate mobile in 30 different locations within a 24 hour period. I'd done some preparatory work, in the way of looking closely at maps and plotting my expected route to know where I was and how far it was to the next location. One of the things I noticed while operating was that my signal reports varied greatly. I also noticed that the local noise floor was quite variable, power lines don't realy show up on a map and I can tell you that they are not your friend. One aspect of operation that took me a little by surprise, though it probably shouldn't have, was that different soil types made a big difference. I know that when I'm playing with antenna modeling software you have the opportunity to specify the soil type, but that doesn't really translate into anything that you can personally experience. The way I mainly noticed the effect is that for any given frequency, my ATU was unable to tune for some soil types, wet was good, rock wasn't. This was the first time that I'd actually experienced that in such a way that I managed to notice what was going on, rather than a theoretical experiment, this was a practical exercise and well worth the effort of moving around. Next time you go out portable, or mobile, have a look at what is happening around you, one of the actual variables is the ground beneath your antenna. I'm Onno VK6FLAB