Solving 20km wireless link issues

RouterOS Wireless Networking
81

Thank you!

82

I am glad seeing this post which has explained the Solving 20km wireless link issues. Well, I am looking for some experts for Data Center Relocation. Please do share some information regarding that.

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Data Center Relocation

83

tgrand is right about the power lines. Don’t forget that electromagnetic field around the cables may also change the direction of the beam or create out of phase waves.
If you have reflected waves that are out of phase, the RX signals of both points will be different.
Looking at the pictures, I don’t see something in you even frensel zones.

Do you observe these changes in RX signals to be connected with the weather conditions, for example with rainfall ?

84

Whats the throughput you have on that distance? the REAL deal.

85

Found this one the internet:
http://j-walk.com/other/wifispray/
Should it improve long-range links and should I try to make an automatic dispensing system?

86

Can you tell me how I can start 20 Km wireless project using mikrotik instrumentation Plz I am in hurry
thanks

mramos 87

88

Mr. mramos

Why you did not mount the antenna in considerable height?
How far your second antenna?

thanks

89

Hi …

Well, it’s not really necessary. Trees at this site have more than 15 .. 20m height. Signal path is 1.6Km. This antenna height have some clearence between the smaller trees leaves and the taller ones (like a window).

I only posted this chart to complement some old posts about moving antenna mount along a flat surface versus the effects reflection of radio signal on such surfaces in front of the antenna can cause.

But even with signal variations this link is in production this way for almost 2 year, uptimes normally more than 1 week. If any disconnection occurr it’s restored in a fraction of a second.

I only “fine tune” its position because I installed there a second grid antenna to give access to 5 or 6 small properties 4Km away and this second antenna was obstructed by a water reservatory. As I need to move it from the old position I decided to search a new spot where those signal notches are smaller than I used to have at the original position.

A bigger tower - to clean up radio path - must have at least 25m. Too expensive to feed 10 customers :smiley:

Regards;

90

Mr. mramos
I have to construct a wisp but I am not sure of the following:
1- Mounting a 24 dbi grid (2.4 G Hz) on a house building height (8 Meter) and the second 24 dbi antenna on the same height with 14 KM far away (Distance between both antennas) but no obstacle between them.
behind these antenna I have 26 dbm transmit power wireless router.
so can I have 26 MB or above bandwidth?

thanks a lot

91

I don’t think it will work.

Even without obstruction in the path there will be earth curvature itself. Small at 14km anyway but it’s there. The main obstacle is fresnel zones blocking.

On such path at 2.4GHz to clear up at least 0.6 F both antennas must be at ~22m height each side. If it was 5.8GHz, for the same 0.6 F antennas must be ~16m each side.

Regards;

92

I am using this calculator : http://www.afar.net/fresnel-zone-calculator
I use equal height antenna section with 0.6 Fresnel zone.
This calculator give 12.9 meter height.
so if I change 8 height to 12.9 it will work Am I right?

thanks a lot brother

93

Well, I took a look at this calculator.

12.9 meter is the radius of 0.6F at the midpoint.

But you have a 14km path so it’s necessary to add earth curvature.

Assuming it’s a perfect surface (like a path over a calm lake), according with this calculator both antennas must be at 15.3m height.

At this height 0.6F at the middle path will have 0m clearence. Rising both antennas to 16m will give you 1m clearence to 0.6F at the middle of the path.

The numbers I gave you before came from another tool (radiomobile) but I simply picked up some geographic area with a “flat” surface (a beach) near my hometown. But I’m not sure how accurate RM can be in this case.

Regards;

94

Can you tell me what do you mean by 1m clearance?
I understood that I have to add the objects reside in line of side eclipse like tree or some unequal earth
Am I right?

thanks

95

1 meter clearence is the distance between terrain and the lowest part of above elipse (where at this wikipedia picture the letter “P” is). In your case I assumed a perfectly flat terrain.

And - yes - you have to add those objects and terrain roughness.

Regards;

96

Thank you mramos I hope you fine and doing well,
If I have clear line of site and 24 dbi grid antenna with 23 dbm output power using 2.4 Ghz unlicensed. I will be able to transmit at least 10 MB or not?

If I use 5.8 Ghz can I get 10 MB or still not?

thanks a gain

97

Of course. If there’s no obstruction nor interference I thing even using 10MHz channel + NV2 (or Nstreme) you can reach 10Mbps. If the cards you choosed are N capable, better. Most of my cards at 2.4 (and 5.8 in near future) are R52nM.

And if you want a PTP solution, there’s Groove for 5G (and 2 GHz in some time I read). No cables, no pigtails, just attach them at the antenna connectors and that’s it.

Take a look at some examples at the forum, several success stories > 20Mbps.

Regards;

98

Hello dears,
How I can make surveillance setup for my WISP using google map or something similar?
this action will help to mount the antenna truly.

thanks

99

wow Nice job !!! congratulation

100

Hi Seniors . . .

Thanks for useful post ,yet i experienced with this issue on 45km link backhaul,
Thanks again to my seniors.