In a message dated 11/07/2008 20:12:45 GMT Standard Time,
tony_g_ireland@... writes:
Sorry
if this is a silly question, but is height ASL any advantage while working
tropo?
Hi, Tony,
No it's not a silly question. It all depends!
Height can be important if you are above the tropo inversion layer,
say a thousand feet or more. It can also be important if you have local
obstructions - that is, within, say a couple of miles. Even then you may be
able to use the local obstruction as a reflector, although not so much on 23cm
as on higher bands.
Much more important is that the antenna can "see" the distant horizon, and
maybe that's where height become more important - or just accept that there may
be some directions in which you can't work!
Antenna height at a fixed location is always a compromise between
"seeing the horizon" and antenna feeder losses - not important if you can
place your gear at masthead, 'cos there's then virtually no feeder loss on
either RX or TX.
Best advice, use 'JNT's Geog software (or other, if you have access) and do
a "scan" of your topography out to, say 50km. That'll give you a fair idea of
what your takeoff will be like. Then plan from that!
