Jake,
Add in that list that they are more noticeable (ugly?).
Does one need guying on a tall antenna? Guess that depends on the pole and how the antenna is constructed. If in doubt, why not?
The above sea level doesn't mean much, but the above ground level certainly can.The -best- height for any VHF/UHF antenna is twice as high as anything within 50 miles of you. Everything else is a compromise. Uh, yeah, right. Not exactly the most practical thing to try for, is it? Oh well, you get what you can and then quit worrying about it.
A few feet can certainly make a difference in some particular cases, but in most cases won't make a huge difference. I've got one dual-band antenna at about 20 feet and another just like it at about 10 feet. I can't tell that it makes any practical difference at all. One of them was a replacement of a shorter dual-band antenna, the larger one definitely did make a difference. The second antenna is for a different purpose but I've tried swapping to see the differences. There was no significant difference attributable to height. There are definite differences, which were surprising though. The lower one using 'worse' feed line had a better match than the one higher which uses LMR-400 feed line (both antennas are non-tunable). I haven't arrived at a definite reason for that yet. (I Doubt if I'll go to the trouble either, since the differences just ain't huge.)
So, when you get that thing to about a 1/4 mile above ground level, quit. Oh, and remember to light the @#$ thing or the FAA will get mad...
- 'Doc
