Neal wrote:
> 
> 
> It is my opinion that precipitation should still be considered in
> calculating propagation reliability for both major nodes (operational
> fixed, i.e. Tower to Walker) and street downlinks (AP to mobile, i.e.
> Walker to Loring Park laptop). With some of the downpours and
> electromagnetic disturbances in the Cities, I would <not> rule out the
> effects of these conditions.

I agree that it should be considered. I've seen the 2 gig studio to
transmitter links for some of the local TV stations and the 5 gig
satellite dish to IDS link for the local MDS company fade during hard
rains but we don't have the option of using  large fade margins like 40 
db. We just don't have that much transmitter power to play with and 24 
db is the largest common antenna size I've seen. 

With 30 mw transmitters and 24 db antennas a 10 mile link only has 
about 10 db of fade margin. Plus this isn't taking into consideration 
interference and the higher noise floor that we're going to be seeing 
as the band gets more crowded. I've heard enough people say that 10
mile links are doable that I think it should work. I think we'll just
have to get something up and running and see what the error rate ends up
being. If it ends up being a problem we can start looking for more
antenna gain or add amplifiers.



> 
> IIRC, I read a propaganda sheet from a manufacturer of ACSB (Amplitude
> Compandered Sideband) equipment that noted of the failure of an 800 Mhz
> (trunked?) system due to rainfall in Florida.
> 
> Neal: nkras at nkras.dsl.visi.com
> 
> _______________________________________________
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-- 
Bryan Halvorson
bryan at edgar.sector14.net