I have read lots of posts on this topic but can't find answer to my questions, which are:

1) am I supposed to use ONLY Mimo antennas on this board?
2) can I use only one antenna on this board? i am getting terrible packet loss although i have tried many things like reducing output power, etc.
3) if I must use two antennas on two chains, do they have to be only Mimo or others will also do?

thanks for shedding light on dark areas.

I have read lots of posts on this topic but can't find answer to my questions, which are:

1) am I supposed to use ONLY Mimo antennas on this board?
2) can I use only one antenna on this board? i am getting terrible packet loss although i have tried many things like reducing output power, etc.
3) if I must use two antennas on two chains, do they have to be only Mimo or others will also do?

thanks for shedding light on dark areas.

1) NO, you can use single pol.
2) Yes you can, then disable Chain 1

Thanks. I don't understand then why I can't connect! When I am very close it connects but as soon as the antenna goes on the tower and although I see good signal strength, it just doesn't connect! I thought it was too strong signal issue but then why it would connect without any problem when i am next to it and not when i am away from it although signal strength is fine?

Just in case, I have connected an omni (normal 2.4GHz) to chain0 and enabled it in the config and disabled chain1. I have also checked channel number and used a right one. Have also tried various options like enabling / disabling short / long preamble, etc.. nothing works. I tried to connect by going close to antenna then walked away while pinging but when i went inside the room, it stopped working, EVEN THOUGH the signal strength was good enough.

Well I was told by the vendor that this AP will support 200 concurrent users (!) so I assumed at least 40-50 may be supported, and the hardware specifications convinced me it would do the job. I used different antennas. high gain omni, sector but didn't work so I am now trying with a 5dbi normal omni antenna connected directly to the connector without additional RF cable and mounted say around 50-60 feet high from the ground (on the roof of a 4 story bldg).

The following image taken from a previous thread shows what I have done. Both the box and the antenna are mounted together on the roof. I have attached an omni antenna to the connector. No other antenna is connected, inside or outside except one omni, meaning I have connected the omni to channel0 thru that tiny cable shown in the image. No other antenna. Hope this makes things clearer.

Sorry I misread the topic title (or you edited it?), I thought you mean RB751. If you use RB711, of course the is no problem using it on a tower, and it was designed to be used like that.

No I didn't edit.. it's about RB711 only. I have noted lately using some new gadget that the packet loss is there due to weak signal but what I can't figure is if a 500mw radio can give strong signal and good throughput why not a 1w radio! Yes I have read and followed and tried many ways to get it working but some mystery... the vendor is now telling me to buy two MIMO antenna saying this device is not compatible with normal antenna.. obviously he is being over smart or ignorant but I still want to make it work.. Could it be the issue with antenna connectors or shouldering issue? I have not shouldered yet as I was not sure if connecting single antenna to channel0 was correct.. Can you confirm this also as I have read different opinions about that too. Thanks.

No reply?

If you want to use a single chain antenna, you must disable the other Chain in RouterOS wireless settings (use Chain 0, disable Chain 1). This is because your device has two chains, and supports a MIMO antenna.

An amplifier is rarely a good idea, generally they also amplify noise, and in rare conditions they will improve anything.

Thanks.

If amplifier (I believe you meant external antenna) is not a good idea then I don't understand how is this device supposed to be used? BTW, antenna channel1 has already been disabled.. thanks for confirming it as i had doubt about that too.

Anyone?

Thanks.

If amplifier (I believe you meant external antenna) is not a good idea then I don't understand how is this device supposed to be used? BTW, antenna channel1 has already been disabled.. thanks for confirming it as i had doubt about that too.

The device has built-in amplifiers. Simply connect an antenna of adequate gain (depends on distance, terrain and other things) and point to the other device. This should be enough.

Please give us more info about your setup, so we can make recommendations.

I have done what you mentioned-- connected a high gain omni antenna to the device as shown in a previously posted image. I am trying to use this device as an AP within 1km radius. I am using a 500mw radio for this purpose and it works great but I need to boost the signal strength and that's why I am trying to replace it with this 1w radio but the signal strength falls beyond 20 meters or so while crossing one slab on the roof. I just can't figure out what the heaven the problem is . My increasing doubt is it doesn't transmit enough output power (?).

Thanks for offering to recommend. Well, in short, we have covered around 1 to 2 km radius area and serving around 100 users by using three AP and some switches on different locations but many users are forced to use CPEs as the area is crowded with multi-story buildings. I am trying to reduce the need of CPEs as they cause noise, need to be regularly maintained, and use them only when absolutely needed. Also there are literally hundreds of wireless routers / devices around that cause disturbance... I am _not_ thinking of 5Ghz links as many devices don't support it as yet. Also they are expensive as of now. This may not be enough info for you to make a recommendation but I hope it gives some idea. My intention is to keep the text short, as much as possible . Thanks.

What kind of devices to the users use? Increasing the AP power will not help in this situation, as the users must be able to transmit back too. Their "amplifiers" should be increased then as well.

So a better approach would be to use higher gain antennas on both sides.

All kinds of devices as the area is filled people from many countries who use so many wireless devices.. b/g/n, like mobiles, tabs, laptops, they also use dongles, mobile hotspots, etc.. those who use desktops use CPEs. My focus is on laptop and tablet users as the number is exploding.

Any suggestion?

Apart from that my confusion still remains as to why this router board has weak signal? What is the default output power?

Let me ask a rather straight question-- has anyone found this product or a particular batch to be defective or buggy? My warranty ends soon and I would like not to spend time on this if the product itself is known to be problematic. The vendor is a complete non-technical fellow and thinks or at least says that I need to buy mimo antennas but I can't agree with him and you all have confirmed that's not the cause. Would appreciate clarification. Thanks.

Alright friends! I joined this forum to get answers to some questions. I did learn something but didn't get answers to all my questions. Nonetheless I want to thank all those who gave some input. I think there is a problem with the antenna cable that connects to chain0 or the device is faulty. Anyway. Thanks. Hare Krishna