ORIGINAL: EASYTIGER
I've got one, it's an older ICOM, the R-2(?) I think, it's not as selective as the newer ones, but still does the job. I USED to keep it in my TX case, and stopped, because I never used it. Wish I had it with me the other day...
Each and every unfamiliar field I fly at, I do an R-2 scan from the flying site, and from surrounding roads or access points. The R-2 is selective down to 5 kHz plenty for our purposes. Scan all of our channels and more importantly scan all of the pager primary channels. The one's 10 KHz up or down in-between each of our channels. Do a goggle of transmitter and antenna location's in the area of your field.. you might be surprised and find out you've been very lucky for years. The frequencies and power output of those transmitter's are public information.
Lee