Web lists-archives.com

Re: Any directional antennas recommendations?




On Saturday 24 November 2018 06:28:01 Alexander V. Makartsev wrote:

> On 24.11.2018 3:41, Hubert Hauser wrote:
> > Hello!
> >
> > I need to connect to a distant Wi-Fi network. I consider buying a
> > parabolic antenna. I want to have 10 km range and long
> > amplification. Will TP-Link TL-ANT2424B be a good aerial?
> >
> > --
> >
> > Best wishes,
> > Hubert.
>
> According to specifications of the TL-ANT2424B you should be getting
> around 30Mbps. [1]
> Of course, you have to install antennas on both sides, as Doug already
> suggested, to make them "talk" in both directions and also make sure
> there are minimal possible obstructions between them, especially
> concrete or wooden buildings, trees, high voltage power lines, etc.
> You have to mount them on a poles long enough to compensate for
> horizon curvature and direct them at each other to get maximum
> possible signal strength.

We have a criteria for that, called the first fresnel zone clearance for 
determining the clearance needed to get past any obstacles in the path. 
That diameter varies with the distance and calculations must include the 
earths curvature. That criteria is that a path straight between the 
points, must be clear by a wave length increase of the path caused by 
the signal if it diverges from a straight line far enough to add 1 
wavelength to the path at that frequency as if the surface in the middle 
that it was glancing off of was a mirror. For really long hops, that 
clearance distance can be 100 feet or more. 

For a 90 mile hop at 7 GHz we had to go cut brush that wanted to be 
trees, on top of Pine Ridge (not the SD reservation town by the same 
name) between a microwave site on Battle Mtn SD, to the middle of the 
plateau of the Agate Beds National Monument in western NE. That was part 
of a 2 way path from Rapid City to the monument pulled off by cross 
polarization, tight filters and 1 watt transmitters. The southbound path 
turned east to KDUH-tv so we could switch the programming in Rapid City, 
SD.

> Also keep in mind that this setup will be prone to weather conditions
> like rain, snow, wind and could temporally make signal strength worse.
>
It's also subject to the sun rising and falling. About 30 minutes of 
cyclic fading for each transition. But they don't tell you that in 
school. :(

> [1]
> https://www.tp-link.com/us/products/details/cat-5067_TL-ANT2424B.html#
>specifications



-- 
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>