distance calculations

RouterOS Wireless Networking
1

how can I calculate the relibality of a connection between 2 R52 5Ghz each one is connected to 13db Omni antenna ,distance is 3km ?

is there any simple calculater for this ? not thise complicated ..

2

I’m not sure about the accuracy for the following ‘Link possibilty calculator’,
http://wiki.mikrotik.com/wiki/Wireless_Setups

But the better option is to perform test on the real environment (as more factors might influence to the link realibility, as calculator is not aware for hidden factors), if you have such opportunity to test antennas on the real conditions.

3

thanks alot , its good simple calculator ..

I found that is if i use R52 and long cable >10m then i cant make a relibale link for 3Km distance with 5G band , so how do MT users overcome this issue ? if they want to make thier MT-PC an AP ?

Point 1 : MT box + R52 5Ghz -----50m height------ 13db omni antenna
Point 2 : R532 + R52 5Ghz --0.3m lmr400 -------- 13db omni antenna
distance = 3Km

4

http://www.cplus.org/rmw/english1.html

this will tell you with a very high degree of accuracy what the link will look like.

5

5.8 also attenuates alot more through lmr400 than does 2.4.

Also something to note, as I have made this mistake before, was that I once accidentally used a lightning arrestor which was only rated for up to 3GHz, and it took me quite a while to realize that I had accidentally swapped the <=3Ghz and <=6GHz arrestors.

Also to note:
Most 5GHz antennas come in 5.2 then 5.8.. Be sure you are operating in the correct range for your antenna.

6

is there any suggestion to use MT PC as an AP with 50m lmr400 cable ?

using the links above result that its impossible to make that link , if I switched to 400mw SR5 it will be reliable , but if the other nodes is R52 is it compatible to make WDS link between SR5 and R52 ?

MT + RB14( SR5 + SR2 )
I
50m cable-----13 db omni ==== 13 db omni—RB532+SR5+SR2

and what about putting 2X 400mw SR5+2 in the RB14 ?

7

Just my experience, 2.4GHz, 150mw, 10.5dBi omni with short LMR400, one on top of a 130ft tower, clear line of site, one on a pole, about 12ft, same config.

a hair over 1 mile away, the 10.5dBi showed little improvement over the stock 2dBi rubber duck antennas. Both of these 10.5dBi antennas have been used successfully on access points with good results, but they absolutely suck as clients.

8

Omni antennas are not supposed to be used on clients. Use directional antenna.

9

its a Mesh WDS nodes , so I have to use Omni antenna on each node , whts the alternatives ?

and I have to use the MT box as the main AP far from the omni about 50m.

10

Don’t mesh using WDS and single radios - it’ll end in tears. Use multiple radios, P-P links, highly directional antennas, and do your meshing at L3.

11

I will use 2 Radios , 5G for Wds link and 2.4g for clients , but how can i use directional antenna if i want to make mesh WDS , i mean to connect an AP with 2 other AP’s ?