Moving from ePMP 90° sectors to 60° Dual Horn antennas

We are looking to change a site over from the standard 90° ePMP3000 sector antenna with smart antenna to the 60° ePMP3000 Dual Horn MU-MIMO antennas (C050900D025A). We currently have 4 90° sectors, which will become 6 60° sectors after the swap. Does anyone have information on frequency re-use on the Dual Horn antenna? We are ABAB with the 90° sectors using 20Mhz channels. Would we be able to do ABABAB with the 60° antenna or will we need to look at ABCABC instead? Is there anything else that would need to be changed in the APs, such as changing the Downlink Antenna option away from Sector?

Thank you for any advice!

Hi. How far are your clients on your existing sectors? If you do a Monitor → Wireless and then sort by SM Distance, what are your ranges to the nearest and farthest?


Keep in mind the dual horn only has 12dBi gain and that is only in the 5.8Ghz bands and more like 10dBi in the other bands. It also drops off really really fast the farther from the center of the pattern you get… in 5.1Ghz and 30° off center you have less than 5dBi gain (and even 5.8Ghz is only around 6dBi ?) .

If you were using DFS channels then the client radios don’t get to use the extra PTP Transmit power so the very low gain of the horns will bite extra hard.

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The furthest customer at this site is around 6 miles out, maybe 50% are under a mile. We are using non-DFS channels in the 5.7-5.8 band.

Could you tell a couple words about the purpose of this change?

We are adding sectors to help better re-distribute clients and reduce latency. The proposed change has been planned in LINKplanner by others on our team, but the question came up about whether we would be able to use the 2 existing 20Mhz channels at the site as ABAB, or if we needed to find a 3rd 20Mhz channel for ABCABC.

In my experience:
1 mile will work really well
2 miles will probably work OK if you have higher gain client antennas.
3-6 miles will not work very well at all with these low gain horns in my experience.

As well, you’ll want to check the antenna beamwidth… I think Cambium is doing a UBNT thing with the “60 degrees” on the horns… that’s -6 db loss at 30 degree off-center I think, which means you’re down to less 5ish dBi gain near the edges of these horns. To be fair, these Cambium DualHorns are really targeted at short range and high interference areas, and for that they work GREAT. But it’s not really designed as a solution for SM’s out past 2 miles.

So… I realize that wasn’t what your question was. Your question was about channel reuse, and I’m normally hesitant to confuse the question with un-asked for advice. BUT, in this case, your channel plan might be immaterial if the clients no longer have enough signal, and they only modulate at MCS3 or MCS4 after changing the sectors out.

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you would not use an ABABAB reuse plan, you would use and ABCABC plan.
You would be better off with 8x 45deg sectors where the AB plan works. Then again, if your going to spend that kind of cash then maybe a 450M may be in order!

I too completely ignored the question asked and offered un-asked for advice. I have seen white papers and examples of other ISP’s doing 60° or less horns and none that I am aware of did ABABAB all did ABCABC. Also Cambium has from the beginning of time recommended ABC for channel planning for 6x60° sectors.

All of that said I personally don’t know why ABABAB wouldn’t work with 60° horns (especially 60° horns that aren’t really 60°, I don’t think it’s going to work well but not because of ABABAB). I would not do it with normal sectors probably but I don’t see why horns wouldn’t be OK. Now, if you have other towers in the area then ABCABC really is better for avoiding self interference from subscribers and ap’s on other towers.

I think with those distances and doing ABABAB (and the lower RSSI you are going to have on distance clients) you will need to be sure you use “Subscriber Module Target Receive Level” to keep the close to the tower client radios from blasting the other two same channel horns hard enough to make trouble for the distant clients on the the other two same channel horns.

Thank you all for your input. We will go with ABCABC and keep the other recommendations under advisement.

Based on the information provided by other users here, as well as information on RF elements forums, we have decided to pursue other options for this site.

What did you choose?

We are adding 450i 3G sectors in addition to the ePMP


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