On Fri, 21 Nov 2008, kf0m wrote:
> I have a friend who had a similar problem trying to get enough signal
> from the main site to his house. The Internet company guy was ready
> to say it just couldn't be done for his location and distance. He
> asked the guy to come back the next day for one more try.
>
> In the mean time, he hauled an 8 ft satellite TV dish up the ham tower.
> pointed it in the right direction and then hung the internet link antenna at
> the feed point.
I have two questions: What kind of tower did he have, and what was the
windload like on that sucker? I cannot see Rohn 25 holding an eight-foot
satellite dish in the air for very long without all of the parts
succumbing to gravity.
> next day the internet tech took one look and said it will never work because
> you have the link antenna pointed the wrong way. My friend said humor me
> and give it a shot. Much to the techs amazement the signal was plenty
> strong and he was able to finish setting up the internet connection.
A large number of "techs" in the Part 15 wireless sector came out of
computing as a hobby, and don't have much of an education as far as RF
goes. If you are lucky, you'll meet a few who know how to calculate
Fresnel zones and path loss. Many have no concept of solutions outside
of the hardware they may purchase, and furthermore to retain compliance
with FCC Part 15, must source system components from a company that has
tested them to complaince.
> So finally getting to the point, find a surplus satellite dish and maybe you
> can get enough signal at a lower height to get enough separation between the
> 2.4 GHz system and the repeater.
The problem with using satellite dishes is that one must compute the
gain, and accordingly lower the Part 15 device's transmitter power to
remain in compliance with Part 15. The nice part about any parabolic
dish is that regardless of the frequency, the feedpoint is in the same
physical location on them.
--
Kris Kirby, KE4AHR <[EMAIL PROTECTED]>
But remember, with no superpowers comes no responsibility.
--rly
