1) My house has a metal roof. What distance from the roof should I mount it vertically and/or laterally?
I'd certainly try to get it above the top edge of the roof, otherwise the roof will block it
in some directions. A mast secured to the wall that gets it just up over the edge will
2) Somewhat related: I know the higher I mount it the better (height above average terrain). However, the higher I mount it, the higher the coax losses. I can calculate transmission line loss, but how do I weigh in the effect of height? At what height are your losses from the line going to be higher than your benefit from getting the antenna higher?
Height trumps coax loss in almost all situations.
For example, going from 20' to 50' increases the 2m signal strength about 8dB (at least
for a particular set of conditions that I modeled.) Even using RG-174 coax (which is
about the lossiest type in common use) the coax loss in 30' of coax would be about
3dB on 2m, leaving a 5dB improvement. RG-58 would have less than 2dB loss, for a
That's not to say that you shouldn't choose a better feedline when it is available, but
that it would require a VERY lossy feedline to overcome the advantage of the added