I want to use Mikrotik products for a new wireless link, but this link is not like my previous links because it is over the sea and I worried about water steam and reflection. So I decided to contact you and hear your suggestion for this new link. I work at a company that is Internet Service Provider in the south of IRAN. Could you please tell me how can I do this? which antenna, routerboard, wireless card should I use? And please tell me other things that you think help this wireless link for stability! Dual Polarization or nstream Dual, Which one is better?
I want at least 20Mbps throughput. Here is some information:
Link Distance: 57.2 Km
Point A: 28° 58.044’N - 50° 50.223’E
Point B: 29° 12.872’N - 50° 19.294’E
hi my friend
i don't have over sea experience but here is some suggestions i hope you work this out
use kenbotong 32 dbi dish in the both side , they are available in iran i've been using theme
XR5 is a good choice ,
and 411AH as board , and 3A Poe
buy the best pigtails you can buy
try this and if you link wan't stable enough , use dual dish in same size and 2* XR5 for each site
if you diden't get you expected throughput use 40Mhz
wow, thats quite HUGE distance for Wi-Fi
i wish you luck in that. friends of mine triend to set-up such things and said was most hardest part was [laser-based]justification of narrow antennas.
more expected to see 2m and 70cm traffic with extra/violating outputs and directional antennas.
or ROS links over 11m ISM band :[
p.s.
if you had license/permit you can buy/use 180Mhz/450Mhz modules, btw
Don’t think that the distance is the biggest problem but weather might be.
I would use dual polarized 32dBi dish with radome on both sides and high power 802.11n cards (F50N-PRO or SR71-15) - you should get -60dBm or better signal level.
Aslo, to reduce losses on RF chains and improve overall stability try to get antennas with integrated routerboard housing to avoid need for RF cable from pigtail to antenna.
At what height will the antenna’s be, have you got freznel zone clearance, is there a option to reduce the distance between A to B from the map further north appears to closer to “Khark”
In a previous life I engineered data links to oil production platforms in the uk north sea.
The problem is this, on a calm day the sea is a good reflector, and you get two signals hitting your receiver, one direct and one via reflection.
This causes two problems:
Delay spread, because the reflection takes a longer route it arrives a few microseconds later, causing errors of phase in the modulated data.
RF signals arriving out of phase and cancelling (fading) the link.
I have seen a 7GHz 15km 8Mbps 8psk professional link with 20dBm TX and 1.2m antennas suffer a 40dB fade and drop out due to reflective cancellation.
It is a real problem if you want high availability over a sea path.
Options for improvement:
Site both antennas so they can see each other but cannot see the sea…(no see the sea no see the reflections).
Use space and or frequency diversity, basically two links on different frequencies on different antennas different distances up the mast. hopefully both links will not fade at exactly the same time, then use interface bonding to send the same data over both links at the same time for a hitless solution.
I have seen links of 80km work ok with diversity.
It is cheap enough to try with mikrotik, high power cards and a big dish..
Consider building two links, maybe one on 2.4GHz if you can get away from local end interference.
