Re: 1.2Ghz opperation...


mikeg3pfr@...
 

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!
 
Regards, Mike, G3PFR
 
 
 
 

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