[VHFcontesting] Optium antenna height
nate at natetech.com
Fri Dec 1 14:50:04 EST 2006
John Geiger wrote:
> Another local VHFer and myself were having a
> discussion as I was driving to work today about
> antenna height for VHF. One thing we wondered about
> is if there is an "optium" antenna height for VHF, or
> is "higher always better." Is there a point where the
> extra height isn't worth the cost of tower, coax, etc,
> and the extra loss in the coax-in terms of the
> increased distance you will work? Or does extra
> height always outweight these other factors?
> 73s John W5TD
Kinda a "tongue-in-cheek" response but...
If there's a maximum height, I'd better go pull the club's VHF and UHF
repeaters that are at 11,440' MSL (which averages 'bout 6000 HAAT around
here) down and move 'em to the lower site!
Granted, if you get all the way up to space, path loss becomes a factor.
(Hint: AMSAT has some studies in their old papers about VHF+, of
course... interesting reading hiding in their stuff.)
So yeah, there's a break-even point for your power level vs. path loss
somewhere on the graph where altitude vs. losses would cross. Don't
think you're going to find that it's anything to worry about
I think the other responders covered the reality of the question for
what you're really looking for though -- if you're just going for
line-of-sight, up is always better... but there are some studies out
there on other forms of propagation...
And clearing any surrounding objects is the real key. You'll lose more
RF in your neighbor's tree if the tower is below that than anything else...
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