We run an ISP and are going to try putting up 4 - 90deg 2.4GHz horizontally polarized sector antennas on our tower. Each sector will be driven by its own radio. Each radio will consist of a RB-532 and an XR-2 radio card. My questions are, should each sector be on its own frequency and should the SSID of each sector be unique? Anyone have any other suggestions to get the best possible service from this setup. Any advice would be appreciated.

Thanks

Jay

Defnitely use different frequencies. The SSID is more up to you... Either way has it's advantages and disadvantages. If it is the same, you may have clients switching back and forth between sectors which can cause problems. Keeping them the same makes configuration easier...

hi, i´m doing the same. how would you suggest setting channels?



which option do you recommend? have any other suggestion?

sorry for my poor graph (next time i promise to use a better soft than ms paint jajajaaa)

Use same frequency, I prefer channel 1.

Let me explain why just same frequency:
You'll use 90 degree antennas
so actual signal will go 90 degree way
so you won't have overlapping on your system.

Even the best sector antennas in the world only have about 30db front to back ratio.... so if you put everything on the same channel, you are going to kill yourself once the sectors become loaded.

The best option is 3 x 120 degree sectors on channels 1, 6 and 11.

Even the best sector antennas in the world only have about 30db front to back ratio.... so if you put everything on the same channel, you are going to kill yourself once the sectors become loaded.

The best option is 3 x 120 degree sectors on channels 1, 6 and 11.

Or use a band where there are more nonoverlapping channels.
Or go down to 10MHz channels.

Stefan

thanks for your replies...

i have already bought 4x90° antennas, 4 radios, 2 rb333, etc etc

i asked my provider and he told me 4x90° is better than 3x120°... maybe it's because he wanted to sell me that hardware jajaaaa. poor me...

now i have that hardware... what it the best choice for me now? look at my graph in the first post & tell me what would you do if you were me?

another question... but don't forget to answer the first one

why some sectoral antennas have inclinations (i don't know if this is the right work in english, i mean pointing to the floor)? look this pics

it is not pointing the floor.
It is up to you. If you want you may point it to the air.
Pointing floor means: You have a long tower or your antennas staying long place and your customers will be lower place than your antenna. So you are turning your antenna to your customer's house's roof.

u can use this and antena http://www.ral.ro/php/produse-32 S50-2500 - Splitter wireless and put the antenas that are on same frecvency back in back

Use channels 1,5,9,13, they don't interfere.

You'll use 90 degree antennas
so actual signal will go 90 degree way
so you won't have overlapping on your system.

That's crazy talk. Of course they overlap.
These are radio waves you are talking about, not lasers.
Look at the radiation pattern in the spec sheet for the antennas.

You'll use 90 degree antennas
so actual signal will go 90 degree way
so you won't have overlapping on your system.

That's crazy talk. Of course they overlap.
These are radio waves you are talking about, not lasers.
Look at the radiation pattern in the spec sheet for the antennas.

Yes. Neighbor antennas and channels disturb each other.
The signal patterns of antennas and channels are not so clean as
numbers tell. This is physically not possible. When using 2,4GHz
you have to live with this.
So separate Antennas and channels as much as possible.
I use 120Degree at 5GHz so I can separate Channels better and I can
fit backhaul and 3 Sektors in a 600 Board. Outdoor-Case with short
cable run. Works like a charm .

Stefan

Use channels 1,5,9,13, they don't interfere.

i can't use channels 12&13 in my country. only channel 1 to 11

Use channels 1,5,9,13, they don't interfere.

i can't use channels 12&13 in my country. only channel 1 to 11

Use 1, 4, 7, 11.

Use channels 1,5,9,13, they don't interfere.

i can't use channels 12&13 in my country. only channel 1 to 11

Use 1, 4, 7, 11.

distributed link option2?

wht all you people think abt putting 2 hyperlink sector antenna of 180 degree...many people think that if u place two sector antenna(180 degree) it will reduce interference...but some people says that placing two 180 degree sector antenna is not a realiable soluiton...i too hav seen evrey man is interested in putting three 120 degree sector antenna... i hav not seen any person having place two 180 degree sector anetnna...why so?

To me the answer is simple: cost and performance.

I can buy 5 of the 120degree sectors for the same price as 2 180degree sectors of approximately the same gain. And the 120s have a wider (actually deeper? vertical) pattern!

1. Using splitters/combiners is stupid.

2. At 20mhz there are only THREE non-overlapping channels, 1,6,11. If you split them into four channels as suggested you WILL have problems.

3. Downtilt is important but not too much downtilt.

4. The only way to use 4 channels on 2.4ghz and get decent performance would be to use 5mhz or 10mhz spacing.

5. Remember range increases as beamwidth decreases. You will get more range out a 120* antenna than a 180*

6. You will also get more range using 5mhz or 10mhz channels.

7. The more sectors you have, the better off you are. You will have more AP's to service more customers. You will also be better as you have to deal with Interference.

well Mr. tim..
i think u are right...but can u plz put some light, that how many users can a good sector antenna can afford..both(120 degree and 180 degree assuming that each sector is connected wid a seano 2611 cb3 plus access point.
thx...

It is not a matter of users as much as traffic to my setup. But roughly, my AP radios handle 20-25 users each (my RB133s have only one AP radio). The RB333 will handle more radios I am sure. I haven't a site where that limit is being exceeded yet.

If you use one omni antenna with one radio, that is 20-25 users. If you use 2 180degree antennas with two radios, that is 40-50 users. If you use 3 120degree antennas with 3 radios, that is up to 60-80 users.

EDIT: I am lucky in a way. Most of the sites I have are right on the beach, so 120 degrees is open to the Gulf of Mexico. So 2 120-degree antennas cover it.

huumm..ths good...hey can u plzzz through some light on horizontal align sector anetnna and wht abt its vertical align..i hav read in description of manufacturer they give specifications..i m new to sector anetnna..how horizontional align and vertical align sector antenna diffires frm each other and which kind of these two we shd use to distribute internet to our coustomers..thxx

VPOL is what most if not all consumer 2.4ghz equipment uses. So, if you use HPOL you eliminate most of the interference.

That being said, if you are offering a Hotspot service or allowing people to connect directly with their computers HPOL will not work.

humm...tht sounds better so wht would u suggest me (HPOL or VPOL) if i place them on mast at 90 feet hieght while my coustomers are having fixed wireless CPE.

If you are using fixed CPE always go with HPOL

If you are using fixed CPE always go with HPOL

@jwcn thx a lot, its seems to me u hav got a sound knowledge of wifi...do u hav any yahoo messenger ID ...i will be exteremly happy to learn under the shadow of masters like you..plzz drop me a offline messege at (faraz_innocent_heart) at yahoo messenger...
thxx

You can email me directly john dot woodfield at jwcn dot biz

thx..jwcn...
i m liitle confused regarding this polarization issue..is there any specail way to mount a horizontal sector antenna or we just mount it like vertical polarized type...and one more thing i search internet for 120 degree horizontal polarized sectror antenna...but i found only 90 dgree horizontal polarized secotorial antennas..does 120 degre horizontal polarized antenna is not manufactured..
thxxx....and plz specify ur eamil add clearly i dont get it right..

In response to the earlier talk about 180 deg sectors, I did find some low cost 180 sectors. They look interesting, basically they are an omni ant with a reflector. Anyone had any experience with these? I normally use 120 deg; but there has been a few smaller towers where this would come in handy.

http://www.wisp-router.com/wri/itemdesc ... 12&eq=&Tp=

Eric

In response to the earlier talk about 180 deg sectors, I did find some low cost 180 sectors. They look interesting, basically they are an omni ant with a reflector. Anyone had any experience with these? I normally use 120 deg; but there has been a few smaller towers where this would come in handy.

http://www.wisp-router.com/wri/itemdesc ... 12&eq=&Tp=

Eric

Pacific Wireless usually makes good stuff.

if we use HPOL sector antenna, then wht kind of antenna we can use at clinet site..at present i use omni directional antenna and at client site i use 10 dbi patch antenna for short distance coustomer and grid antenna for long distnace coustomer...any idea plzz share wid us..

You can use the same antennas on the client side. They will just have to be rotated 90 degrees.

opppps.
i m helpless, i dont find any vendor who can supply me 120 degree HPOL sector antenna..anyone knows where to get them...
thx and regard.

Where are you located?

well..
i m located in INDIA.

Where are you located?

Does it matter? Have you seen them anywhere?

Yes, it does matter where one is located.

http://www.superpass.com/SPHSG2T.html

Yes, it does matter where one is located.

http://www.superpass.com/SPHSG2T.html

Great! They are located within driving distance and I didn't even know they existed. Good prices too.
I'll have to give them a try.

I doubt they'll have a problem with shipping to India for wireless12.

Their antennas are great, just lack effective mounting options.

I wouldn't call them "great" but they do have their purpose and are certainly a cost effective approach.

look this pics

just an raised eyebrow:
How come you are in Argentine while the pictures are from my supplier in Spain? You'd better buy closer to home with the present usd rates?

Rudy

In response to the earlier talk about 180 deg sectors, I did find some low cost 180 sectors. They look interesting, basically they are an omni ant with a reflector. Anyone had any experience with these? I normally use 120 deg; but there has been a few smaller towers where this would come in handy.

http://www.wisp-router.com/wri/itemdesc ... 12&eq=&Tp=

Eric

Horrible product. The other sectors go deaf whenever one of them transmits, terrible isolation despite what they claim. Unless you are charged tower leasing costs per antenna, get 3 x 120s and spread them out, you'll do far better than this product. Wish I knew how bad it was before it ended up 180ft in the air...

I plan to use 90 Array antennas with following setup:

Sector front CH 11

Sector back CH 11

Left CH 6

Right CH 6



TOP Omni backup antenna CH 1

That won't work. Well it will but it will be ugly. You need to use 5mhz or 10mhz channels otherwise the self interference will be awful.

Thanks for quick respond do you have any suggestion with current setting?

For now we have the Omni antenna.

On this week we are going to turn on the array sector antennas.

This setup will be better? Please help

You can't use 20mhz channels like you are trying. There are only 3 non-overlapping channels and you are trying to run 5 antennas. It doesn't work.

So there no way to setup the site with 5 AP? or I should remove the omni from the top?

Assumes I remove the Omni from the top what is the best way to setup my current antennas.

Use 3 120* sectors instead of 4 and lose the omni. Otherwise drop to 5mhz or 10mhz channels.

Well the problem is we spend on 4 90 sector antennas. If they wont work why still sell those antennas GRR! any solution to me?

Well, they will work, but if you use them the way you want to, they will interfere with each other. As JWCN said, if you use 5mhz channels, you have many more non-overlapping frequencies to choose from, but you'll also lose support for laptops, etc.

Your best bet would be to return the 90's and get 3 120 degree sectors. You can still have the omni, but it would be best to leave it shut off until you need it

There is more to 2.4ghz than just 20mhz wifi. They'd probably be great antennas for a frequency hopping system (1mhz) or using 5/10mhz MT.

Why not simply put them all on Channel 1 and WDS them together?

Create static WDS links between each interface and add them all to the same RTSP bridge.

Give all of the wireless interfaces the same ssid.
Basically your array will appear as one big antenna.

I plan to use 90 Array antennas with following setup:

Sector front CH 11

Sector back CH 11

Left CH 6

Right CH 6



TOP Omni backup antenna CH 1

I just make test with this setting with no lost db I guess the antenna has good insulation

Why not simply put them all on Channel 1 and WDS them together?

Create static WDS links between each interface and add them all to the same RTSP bridge.

Give all of the wireless interfaces the same ssid.
Basically your array will appear as one big antenna.

If I use Same SSID not cause problems?

BTW what is Noise Floor I have (dBm) -99 on all AP...

Why not simply put them all on Channel 1 and WDS them together?

Create static WDS links between each interface and add them all to the same RTSP bridge.

Give all of the wireless interfaces the same ssid.
Basically your array will appear as one big antenna.

Somebody has tried this ?

what about interferences ?

regards,
andres.

Yes, I have tried this.

Most of the buildings I have antennas on have 3 antennas on them. All on the same channel (ch 13) and all wds'd together. Usually one is ap bridge and the other 2 are wds slaves.

No interference problems at all.

I have found wds very helpful with using a single frequency for an entire network.

Yes, I have tried this.

Most of the buildings I have antennas on have 3 antennas on them. All on the same channel (ch 13) and all wds'd together. Usually one is ap bridge and the other 2 are wds slaves.

No interference problems at all.

I have found wds very helpful with using a single frequency for an entire network.

What about users jumping from one sectorial antena to other ?

can you avoid this ?

Well I tested yesterday I just put all my AP with same SSID.

When users move around they always will connect to stronger signal.

When they switch to other AP will be a reconnection so it’s better if you have all AP on same network to avoid authentication problems.

Sorry my bad English...

Well I tested yesterday I just put all my AP with same SSID.

When users move around they always will connect to stronger signal.

When they switch to other AP will be a reconnection so it’s better if you have all AP on same network to avoid authentication problems.

Sorry my bad English...

What about packet loss when customers stations jump, from one AP to other ?
with this configuration, can you force specific station to connect to specific AP ?

regards

Well they will disconnect and recconect to stronger signal. I guess there is no way to avoid that.
That is the case of my setup... if I put 1 AP and the other WDS no idea.

Well the problem is we spend on 4 90 sector antennas. If they wont work why still sell those antennas GRR! any solution to me?

If use use a WISP designed product, you can reuse channels as you want... This is completly doable with Motorola Canopy..


ahora esquivo! jeje que viva el chimichurri!!! y los Cadillacs!!!

Having all your AP's on the same channel is not going to work. When AP #1 is transmitting, AP #2 and AP #3 will not be able "hear" their customers transmitting.

So, although it is probably working, it will not scale to hundreds of users... you will be stepping on yourself.

Well the problem is we spend on 4 90 sector antennas. If they wont work why still sell those antennas GRR! any solution to me?

If use use a WISP designed product, you can reuse channels as you want... This is completly doable with Motorola Canopy..


ahora esquivo! jeje que viva el chimichurri!!! y los Cadillacs!!!

You are from PR?

Actually with Canopy you can have multiple AP's on the same frequencies - that is what GPS sync is for. You can also do this with FHSS radios such as Alvarion.

Good, thanks

thanks for your replies...

i have already bought 4x90° antennas, 4 radios, 2 rb333, etc etc

i asked my provider and he told me 4x90° is better than 3x120°... maybe it's because he wanted to sell me that hardware jajaaaa. poor me...

now i have that hardware... what it the best choice for me now? look at my graph in the first post & tell me what would you do if you were me?

another question... but don't forget to answer the first one

why some sectoral antennas have inclinations (i don't know if this is the right work in english, i mean pointing to the floor)? look this pics

Downtilt. This avoids the shadow close the the tower

Use 1,5,9,12,13.
You will see that 12 and 13 are spaced 12 mhz apart. Will help you a little, if you intend in keeping all of them.
What I don't get, is why you want the omni...... You should have proper coverage from the sector antennas, and if you need it as a separate interface.... create a vap on each card, with same SSID, and bridge them together in a single bridge, for addressing purposes. Or play with vlans, or something.....

Also, if you can, put the antennas one over the other, in order to have some vertical separation among them, or keep them 2 by 2, the further the channels on them, the better.

What about users jumping from one sectorial antena to other ?

can you avoid this ?

Use access lists with allow/deny, for each wireless interface.

Use 1,5,9,12,13.
You will see that 12 and 13 are spaced 12 mhz apart. Will help you a little, if you intend in keeping all of them.
What I don't get, is why you want the omni...... You should have proper coverage from the sector antennas, and if you need it as a separate interface.... create a vap on each card, with same SSID, and bridge them together in a single bridge, for addressing purposes. Or play with vlans, or something.....

HI!

are you talking about use splitters , with one miniPci card ?

what if you want to have 3 panel 120° with 3 miniPci card, with same "ssid" ?
is possible ?

regards,
andres.

HI!

are you talking about use splitters , with one miniPci card ?

what if you want to have 3 panel 120° with 3 miniPci card, with same "ssid" ?
is possible ?

regards,
andres.

You could do that, but it would be an awful idea ( the splitter). You will be lowering your signal, plus of that, you will be picking the noise from all the sector antennas, and your sector would be no better than an omni, or, better said, it would be worse, with the sole advantage of a "downtilt omni" . Plus of that, the price of a _good_ splitter for 1+3 channels is wayyyyyyy over 200 euros. Just not worth it.
Yes, I am talking about separate mini-pci cards, put in whatever you want ( RB, PC, anything), and configured exactly the same, includind SSID. The difference is that if you do not want your client to be able to connect to sector 3, for example, you put a access list rule for the respective card, with DENY as action, and ACCEPT rules for the other 2 cards, for him to be able to connect to them.
Also, if you want to keep them in the same broadcast domain, for the AP side, you can use bridge, with whatever interface you choose, and all the sector antennas together. Of course you add your addresses on the bridge interface, not on the physical ones.

Yes, I am talking about separate mini-pci cards, put in whatever you want ( RB, PC, anything), and configured exactly the same, includind SSID. The difference is that if you do not want your client to be able to connect to sector 3, for example, you put a access list rule for the respective card, with DENY as action, and ACCEPT rules for the other 2 cards, for him to be able to connect to them.

Thank you, I understand.
How ever, if you setup each mini-pci-cards with same SSID, and same Channel ?
or you mean same SSID and different channels ?

what about interferences with same channel?

thank you.

Well the problem is we spend on 4 90 sector antennas. If they wont work why still sell those antennas GRR! any solution to me?

If use use a WISP designed product, you can reuse channels as you want... This is completly doable with Motorola Canopy..


ahora esquivo! jeje que viva el chimichurri!!! y los Cadillacs!!!

You are from PR?

Si senor!

Yes, I am talking about separate mini-pci cards, put in whatever you want ( RB, PC, anything), and configured exactly the same, includind SSID. The difference is that if you do not want your client to be able to connect to sector 3, for example, you put a access list rule for the respective card, with DENY as action, and ACCEPT rules for the other 2 cards, for him to be able to connect to them.

Thank you, I understand.
How ever, if you setup each mini-pci-cards with same SSID, and same Channel ?
or you mean same SSID and different channels ?

what about interferences with same channel?

thank you.

Absolutely different channels.
see that 1,5,9,12,13........... these are channels....... Of course you can always experiment .

Thank you.

Andres.

a good read:
http://www.wi-fiplanet.com/tutorials/ar ... hp/3756431

checkout the links also.

a good read:
http://www.wi-fiplanet.com/tutorials/ar ... hp/3756431

checkout the links also.

thank you.

Yes, I have tried this.

Most of the buildings I have antennas on have 3 antennas on them. All on the same channel (ch 13) and all wds'd together. Usually one is ap bridge and the other 2 are wds slaves.

No interference problems at all.

I have found wds very helpful with using a single frequency for an entire network.

HI Pikoro,
how many clients/CPE are connected at the same time by Antenna in this WDS setup?
Regards

Geeze can you please start a new topic/thread this one is nearly TWO YEARS old.

Hi Guys,
I start a new topic about WDS experience at http://forum.mikrotik.com/viewtopic.php?f=7&t=42880

I really appreciate your help

Best Regards

See this picture for tilt angle adjustment.

-muhti.

Hi,
every here i need some help i have been installing Mikrotik AP with RB's and omni antenna but i have been ask to make a design that will be able to carry traffic for 600 to 700 current users, should i use sector antenna with RB 433 and what wireless card will be able to carry at least 200 to 250 user. please i will be great full if i could get some help thanks.

Hi,
every here i need some help i have been installing Mikrotik AP with RB's and omni antenna but i have been ask to make a design that will be able to carry traffic for 600 to 700 current users, should i use sector antenna with RB 433 and what wireless card will be able to carry at least 200 to 250 user. please i will be great full if i could get some help thanks.

25 Users per Antenna gives good results. 40 Users is working.
Going higher gives bad results. May be nv2 gives higher numbers
when it leaves beta.

Thanks for your responds which one is nv2? please

Thanks for your responds which one is nv2? please

Use Search Funktion. Read a Lot before planning.

Why not simply put them all on Channel 1 and WDS them together?

Create static WDS links between each interface and add them all to the same RTSP bridge.

Give all of the wireless interfaces the same ssid.
Basically your array will appear as one big antenna.

that is very good idea, please if you explain that some more then they will help some more users

Thanks in advance

See this picture for tilt angle adjustment.

-muhti.

tilt antenna.png

good info

I would like to know if this hypothetical wifi setup can have complications.

I have been trying to solve a problem with cheap implementation of wifi into a building. Everything I have read led me to conclusion that the best way to have wifi in a building is to have an antenna/s dozen meters away from the building because the signal will propagate through the windows instead walls.
Next I thought that the best place for antenna is the building next to the building that shall receive the wifi. But what if the two buildings have antennas pointed at each other? Hence the antenna at the opposite building will secure the signal for the other one, and vice a versa.
Shall the antennas interfere each other even if set on different channels?
10x for any suggestions.

I would like to know if this hypothetical wifi setup can have complications.

I have been trying to solve a problem with cheap implementation of wifi into a building. Everything I have read led me to conclusion that the best way to have wifi in a building is to have an antenna/s dozen meters away from the building because the signal will propagate through the windows instead walls.
Next I thought that the best place for antenna is the building next to the building that shall receive the wifi. But what if the two buildings have antennas pointed at each other? Hence the antenna at the opposite building will secure the signal for the other one, and vice a versa.
Shall the antennas interfere each other even if set on different channels?
10x for any suggestions.

Yea they could interfere it all depend how how wide apart u set the Channels,
Pls also take note that if the signal are not to strong at the point of interference i would not have much effect on your network.

Yea they could interfere it all depend how how wide apart u set the Channels,
Pls also take note that if the signal are not to strong at the point of interference i would not have much effect on your network.

Antennas will be set at each building side pointing at each other with a distance between them around 100 meters. I suppose I will set the channels at 1 and 11, or 2 and 10, something like it. What do you mean with point of interference?

Another thing I am curious although maybe not for this discussion, is if one of the antennas will be the main base station in a WDS. Also WDS requires usage of the same channels, but we already defined them to be different. Does that mean that I can not use anything like WDS. Maybe I will need a third antenna placed with the second one that will acquire the signal from the first one and make it available to the second one so it will be able to retransmit the signal to its clients at different channel. Maybe some small panel antenna.
A strange setup looks like to be forming, but still better than repeaters or AP at each floor approach. What do you think?

No since u are using WDS will be in the same channel and same SSID so there is no need for u to worry about interference and it just the same anterna u will use per access point.

hello guys plz help me out
i m using 2 sector antennas 180 degree each with ubnt bullet m2hp.
one is on channel 9 and 2nd is on channel 11 on 2.4ghz 20mhz.
but i notice they are interfering each other and getting low coverage range.
one antenna signal also comes to others antennas side in 300 to 400 meters.
suggest me best channels to use which dont interfare and extend range.

If you are using fixed CPE always go with HPOL

There are situations in which vpol has definite advantages over hpol (e.g., firing a signal down a city street), and vice-versa (e.g., over water). But as long as the only factor is congestion from consumer-grade equipment, then this is reasonable advice.

You can use the same antennas on the client side. They will just have to be rotated 90 degrees.

I dont understand what does it mean " They will just have to be rotated 90 degrees ". Do i need to rotate the client CPE to work with horizontal Polarisation ?

You can use the same antennas on the client side. They will just have to be rotated 90 degrees.

I dont understand what does it mean " They will just have to be rotated 90 degrees ". Do i need to rotate the client CPE to work with horizontal Polarisation ?

The antenna needs to be rotated 90*. Antenna polarization refers to the plane of the electrical component of the EM wave, which is a function of the antenna design.

The antenna needs to be rotated 90*. Antenna polarization refers to the plane of the electrical component of the EM wave, which is a function of the antenna design

Thanks a lot..
Is there anyway to check the polarisation of Other AP's running in our area....suppose they are on verticle...so its better for me to use horizontal.


Our base station is in Delhi there are lots of interference about 200 AP's found in the survery....The tower height is 120 feet long...and there are 50 - 60 feet houses surrounded by the tower...please suggest me which polarity is better horizontol or vertical.

Is there anyway to check the polarisation of Other AP's running in our area....suppose they are on verticle...so its better for me to use horizontal. Our base station is in Delhi there are lots of interference about 200 AP's found in the survery....The tower height is 120 feet long...and there are 50 - 60 feet houses surrounded by the tower...please suggest me which polarity is better horizontol or vertical.

Short of examining their antennas, you could run a scan on your AP with the antenna oriented in first vertical and then horizontal polarization, and compare the signal strengths. But the underlying question should be, which orientation, frequency etc. gives your links the best S/N ratio? Looking at the EM environment can narrow down the search, but this is something you will need to determine empirically.

hello guys plz help me out
i m using 2 sector antennas 180 degree each with ubnt bullet m2hp.
one is on channel 9 and 2nd is on channel 11 on 2.4ghz 20mhz.
but i notice they are interfering each other and getting low coverage range.
one antenna signal also comes to others antennas side in 300 to 400 meters.
suggest me best channels to use which dont interfare and extend range.

check your other post! http://forum.mikrotik.com/viewtopic.php ... 71#p273871