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jo2jo
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20mile link ?

Fri May 11, 2007 12:47 am

I have the trango broadband link calculator. I plugged in all my custom mikrotik values, and it tells me at 20miles:

the Fresnel radius is 69.66 ft earth curvature is 50 ft and required antenna height is 119ft.

expected signal is -63 as we are using 25db grid dish ant's


not having experiences with this distance of a link
my question is this:

If one end is at 125ft and the other is at 55ft, is there ANY chance this link will work? how strict is the 119.6 required antnna height @ 20 miles.

thanks alot
:beep :beep :beep
 
jo2jo
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Fri May 11, 2007 6:53 pm

quick yes or no..i dotn need an explination.

I know someone has messed with long range links that do not have the required height...

thanks
:beep :beep :beep
 
indianboy
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Re: 20mile link ?

Fri May 11, 2007 7:15 pm

I have the trango broadband link calculator. I plugged in all my custom mikrotik values, and it tells me at 20miles:

the Fresnel radius is 69.66 ft earth curvature is 50 ft and required antenna height is 119ft.

expected signal is -63 as we are using 25db grid dish ant's


not having experiences with this distance of a link
my question is this:

If one end is at 125ft and the other is at 55ft, is there ANY chance this link will work? how strict is the 119.6 required antnna height @ 20 miles.

thanks alot
The Antenna height is required for getting the -63ish signal. If you lower the antenna then you will not get clear Fresnel zone and the signal will drop.

125 ft on 1 side and 55 ft on other side can only be confirmed if you tell the details of the obstructions in the way.

If you have no obstructions then :

Site A Antenna = 119 ft
Site B Antenna = 119 ft

Total Antenna Height = 119 X 2 = 238 ft.

So you can go for either 1 ft Antenna Height at SITE A and 237 ft at SITE B .

Any sort of combination will do as long you don't have any obstructions.
 
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Equis
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Mon May 14, 2007 7:06 am

I do a 40km link with a small pole mounted on a house roof....
It is from hilltop to hilltop tho

I think it will work you will just lose a few db
 
jo2jo
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Mon May 14, 2007 7:58 pm

both replies are very much appricted.. and exactly the answer i was looking for..

i will be setting up two links actually:

1 Low elevation (> 50ft) to 225 FT (5ghz link) will use XR5's and 26db grids - 19.95 mile link, trees only obstruction


2) medium elevation (> 60ft) to 125 FT (5ghz link) will use XR5's and 26db grids - 16.55 mile link, trees only obstruction


i will report back
:beep :beep :beep
 
indianboy
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Posts: 45
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Mon May 14, 2007 9:07 pm

both replies are very much appricted.. and exactly the answer i was looking for..

i will be setting up two links actually:

1 Low elevation (> 50ft) to 225 FT (5ghz link) will use XR5's and 26db grids - 19.95 mile link, trees only obstruction


2) medium elevation (> 60ft) to 125 FT (5ghz link) will use XR5's and 26db grids - 16.55 mile link, trees only obstruction


i will report back
5 Ghz link needs a lot less clearance than 2.4 Ghz . Remember that you will have to do proper down tilt for the high elevation antenna and up tilt for the low elevation antenna.

That way you can catch the maximum signal.

Good Luck for your test and dont forget to post the results.

I am interested in the type of trees which you have as obstruction.

BR
 
danletkeman
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Re: 20mile link ?

Tue Jun 05, 2007 6:18 am

Just finished setting up a 12 mile link.
5.745 20MHZ

Site A:

40ft
532A
SR5
2' Dish

Site B:

200ft
532A
SR5
2' Dish

Signal is around -66 and CCQ is about ~60%

Lots of trees in the way but the link works. I get around 6-10mbit througput one way.

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