@eden: I would not use any narrow vertical beam sectors from any brand to cover a valley from a high point. Due the narrow vertical beam the footprint on the bottom of the valley is only a small distant ring section from AP that gets best signal from these sectors. Special the ubntâs are not a good sector for high towers that have to face down and cover big ranges. I replaced them already years ago for better ones.
Better in that case is the RF elements cone range of antennas but I also use their carrier class sectors. They are soo much better then ubntâs sectorsâŠ
Beam forming, tdma and GPS sync is still not there from Mimosa, thatâs a real setback if youâd ask me and should start to give them the shivers since after almost 2 years of promises and delays yet still not availableâŠ
In the meantime I use one A5-14 with 53 (!) associated clients, all Mikrotik, all at distances from 50 meters up to 400 meters max and the performance is great! Clients are allowed to use up to 25Mbps downloads and we see peak usage of the AP of 50-60Mb at times. We have 2 SXTâs and one Mimosa C5 connected and at any time I can start downloads on these and they all get 40-50Mbps at the same time! (Meaning total througput on the A5 reaches 200Mb!) All ânâ type of SXTâs! I can easy push to their wire speedâŠ
On a single mikrotik CPE (we used a SEXTANT for the gigabit port) we could push a download to 150-200Mbps relative easy while the rest of the network still worked. The C5 we could push even a bit higher⊠I saw a peak of 225MbpsâŠ
This all in a âinteropâ mode (=802.11 legacy) and apart from 1 SXT and the C5 all CPEâs where ânâ models only.
We used 40Mhz channel. We tried 80Mhz for the test which gave the high througput on the Mimosa C5 but since none of the ânâ models do support that and we needed to conserve some spectrum the normal working bandwidth is 40Mhz. And that works fineâŠ
So when it comes to 802.11a© legacy mode this is the best performing AP I have seen for a long time. I am very happy and since none of the connected customers complained (that has been different in the past!) Iâd presume they are happy too!
The only negative I noticed is that it seems sometimes the network sort of collapses when some antennas seem to consuming lots of bandwidth. Iâd presume this is because the âlegacyâ mode since with so many associated stations even the RTS/CTS CSMA helper tool canât stop collisions in the network which brings the capacity down.
But mind you, I only saw this when I was pushing the A5 to deliver 100Mbps to some stations at the same time. Under normal conditions as said I never see the network collapse.
The use of M5âs in comparison to SXTâs is both a pro as a con. The pro is that the dishes are better in isolating from unwanted noise. And for bigger distance you still can get relative high signal levels. (An SXT is only 16dbi).
But in a CSMA network the directional beam is in fact a disadvantage. Since the probability of a âhidden nodeâ issue is even bigger when all clients stations are heavily focussed on the AP only. The simply wonât âhearâ eachother anymore. In tdma this is not an issue, in CSMA it isâŠ
Also their signal gain is too high for short distant associations to the Mimosa. It could be that both on the CPEâs end as on the A5âs end the signals are too high. Signal from CPE to A5 can be tuned down but from A5 to CPE it all depends on the weakest clients youâd want to reach.
I tuned all client stations output power such that their signals âhitâ the A5 in the region of -52/-58dB. First we tuned them down even more but then the stations couldnât âhearâ all the others anymore and the âhidden node effectâ made the network complete degrade to almost useless. I found this level for a cell of about 400mtrs works good.
We also set all CPEâs (well, on the Mimosa C5 its not possible!) to use RTS/CTS at all times. Without this the network is crap⊠(Mind that most CPEâs, Mikrotik, Ubnt, etc by default have a setting not to use RTS/CTS. That is wrong. It should always work, under any circumstances.)
So, this is all in âinteropâ mode, or âmigrating networkâ mode.
To prepare for the future GPS sync with tdma we need to replace all stations too into C5âs. But due the costs and the fact its still not available we developed another plan;
Before converting all our 55 clients that work with the Mimosa into C5âs we are thinking to see what would happen if weâd replaced all SXT ânâ protocol antennas for âacâ units. Its a lot of work but if it would improve the network a bit further then we already achieved (we then could use 80Mhz bandwidth and the higher MCS rates) I might decide not to spend my money on a whole bunch new C5âs but buy more Mimosa APâs for the rest of my network.
After all, for the price of one C5 I can buy almost 3 SXT acâsâŠ
On this moment it doesnât make a lot of sense to spend 3 times as much on C5âs only to squeeze the extra 20% performance gain out of the network once the new promised features finally comes available.
And then again, who is waiting for 200-300Mb clients connections anyway where 20-30Mb is already considered âtop speedâ??
Imho only new deployments that have to compete in dense areas with fibre should go for the full A5+C5âs PtMP package.
For migrating operators just an Mimosa AP in legacy mode already doubles or quadruples your network against relative low investment⊠(At least, with MT that is the case. I read somewhere that the latest âacâ hardware of ubnt is not backward compatible anymore so no use in a Mimosa networkâŠ)
The only other reason to go for a full Mimosa network is when may APâs have to be syncâd to conserve spectrum and that needs tdma and thus Mimosa CPEâs too⊠Is a balance between top performance and money availableâŠ