Superchannel, CM9s, and radios not seeing each other (scan)

RouterOS Wireless Networking
1

I’m out of ideas.

I’m supporting a deployment of a number of RouterOS based wireless nodes overseas. They were equipped with the Custom Frequency Select module, are a mix of RB200 & RB500 systems, and all have CM9 radios.

Before they shipped, I preconfigured them, established links between them, and tested the entire network out in the lab.

Now they’re installed, and aren’t working.

The AP is broadcasting it’s SSID, and a Windows laptop is able to connect to it & transfer data from the SU’s location.

The SU, when set to AP mode for testing, can be connected to with the laptop & transfer data.

The SU, when set in SU mode & pointed at the AP, sees nothing. The scan list is totally empty. I’ve tried manually setting the scan list value to a frequency range that covers the AP’s broadcasting frequency, I’ve tried setting the SU’s scan list to just the AP broadcast frequency, and I’ve tried manually forcing the SU’s frequency to the AP’s frequency, while having either an empty scan list or reasonable values in the scan list.

Nothing works. The SUs flat out do not see the AP. We’ve tried swapping radios in the AP, swapping radios in the SU, we’ve tried different SUs, both preconfigured & creating new configurations, and NOTHING works.

I’ve also tried setting one radio in the SU to an AP, and the other to the station, and scanning - they can’t see each other, but once the mode is switched from superchanel to regulatory domain, they were able to see each other.

I’ve tried all combinations of superchannel/manual tx power/regulatory domain on the AP & SU, nothing seems to work.

Everything worked fine in the lab before I sent it out. There are different antenna cables at the deployment, but the fact that the laptop can see both would tend to indicate that they’re working at least halfway decently. Also, a number of different antenna cables have been swapped in, everything is doing the same thing.

As I said, I’m out of ideas. Does anyone have suggestions? I don’t tend to think it’s software issues, but I haven’t had much time to play with superchannel, and I think we’ve swapped hardware enough that unless all the antenna cables are bad, we’re looking at software issues.

-=Russ=-

2

Well, my experience with superchannel on 2.8, is that you need to specify like this:

5725-5805

in Winbox for it to scan those channels. On the AP, no scan list is necessary. Did you make sure that all the other settings match (NStreme, WDS, etc)? Does a Wireless SCAN show the AP from the SU? If you’re using WDS, is DFS (dynamic Frequency selection) turned off?

3

I’ve tried that format, I’ve also tried just specifying the channel that things are on, I’ve tried comma separated values of a few channels.

Did you make sure that all the other settings match (NStreme, WDS, etc)?

All disabled on both ends. The units were configured before they went into the field and were working perfectly.

Does a Wireless SCAN show the AP from the SU?

No. This is what concerns me. A laptop sitting near the SU can see the AP, but the SU can’t see the AP.

If you’re using WDS, is DFS (dynamic Frequency selection) turned off?

No WDS is being used, but DFS is off anyway. Looking at the status shows that the AP is actually running on the channel I selected.

-=Russ=-

4

What about antenna polarity? Maybe the SU is on Horizontal while the laptop is on vertical? A Horizontal SU (set to AP mode) and a vertical laptop would see each other at short range, where the SU would not see the tower on Vertical.

What about the antenna connector? Maybe you’ve got it hooked to B and it’s set to A (AP or SU side possibly)? The A connector will send a strong enough signal to be slightly amplified by the pigtail and antenna, and will work in a short range, but further away the signal loss will be too great.
The one nearest the corner on a CM9 is A.

Can one AP see the other AP on the same tower with a Wireless Scan?

5

You’re kidding, right? checks

… you’re serious. I think that’s the issue. The cards are set to ant-a, and I know all the pigtails are connected to the center one which, apparently, is ant-b.

I switched one of the APs to ant-b, and started seeing a few other access points on the scan, nothing seen with ant-a.

Well, hopefully that’s it. That would explain everything we were (not) seeing. I’ll have someone on the ground switch the SU antenna port tomorrow morning, and hopefully that will get things cranked up.

I’ll update this as I learn things.

-=Russ=-

6

Many NEWER Atheros cards do have the a-connector near the center. The CM9 has it on the corner.

Source of confusion, yes :wink:

Best regards,
Christian Meis

7

tell that to the card makers. ar least a pri and sec would be helpful

8

Yes, the antenna port was the issue. Someone on the ground changed it to use port B, and everything is coming up online.

Thanks for the help! :slight_smile: I knew bouncing the problems off other people would come up with something obvious I’d missed.

-=Russ=-