On Jul 9, 2004, at 3:13 AM, Bill Pitz wrote:
>>
>
> Not true. Parabolic dish antennas also radiate the signal out the
> rear of the dish. Not nearly as far or as concentrated, but for
> shorter links, you can easily enroll clients in the back of a
> directional antenna... particularly parabolic dishes.
Interesting, not doubting you but I wonder what factors in the dish
itself and so fourth make them act that way. The reason i say this is
when we have been setting up our sites the best be could do to connect
form the rear was within about 10'. Of course when using that sort of
parabolic dish you are trying to throw the signal further out there and
10' isn't what you want. Maybe the solid verses the mesh makes a
difference? Not really sure but good info to test at one point since in
our use it wold make a difference.
>
> Well, the legal aspect isn't really that difficult to overcome. The
> 5W and 10W amps are floating around all over the place. The real
> problem when you couple (relatively) high wattage amps like that with
> high gain antennas (i.e. a 24db gain parabolic dish) is the effective
> radiated power that you create. Obviously, the more the better if
> you're trying to get the signal far away, you can pretty easily build
> something that puts out a level of power that's unhealthy for the
> human body to be exposed to for long periods of time. In other words,
> if you had a 5W amp on a 24db gain antenna, I would not want to sleep
> underneath it, even if it were on a 20' mast :-)
>
> -Bill
>
I agree the legal aspect isn't too much but still you can make someone
unhappy. The military setups I have seen used a 5W to 10W amp with the
24db antenna just as you mentioned you shouldn't. I agree with you
since what I read agrees with you but it makes me wonder what they are
using for shielding?
Anyway, without an amp the antenna should still provide a decent signal
for a good part of Jon's property based on what has been described to
me. Basically a 24db antenna without the amp. Now I could see it one
day and totally change my mind but aftrer seeing setup in cities with
20' to 30' masts and dealing with major roads, buildings, buffer zones,
etc. at a 4 to 5 mile range and actually getting a decent signal to
extend a network i was highly impressed.
Jeff
This archive was generated by hypermail 2b29 : Sun Aug 01 2004 - 00:46:14 EDT