Hello guys, need help with choosing the equipment for one job that my firm is currently working on. We have already on site couple of omnitiks and around 20 of sxts but, lately we had experienced lot of drop links. Now we are looking for new solution and need help for choosing right equipment that would work perfect. This is how it looks on the map:
On central tower we need two sector antenas that are facing both west and east, then we need to connect central tower with fiber optic (green) that is in small office house on west and that link need to be perfect. Also there is very important link (red) that is going from distance (750m) also high priority. Just to mention, the longest link is 350m and the shortest is 75m.
For the Green and Red Links i would probably choose a 60Ghz product, that would be the wireless wire dish.
So 2 pairs of wireless wire dish for those 2 Links.
The sector antennas for the yellow links would be mantbox 15s and for the clients SXTs…
I’m afraid the current equipment itself is not the source of the problem. The first thing I would think about is some interference in the air (which may come from the manufacturing technology on the site or from other wireless links in nearby area). The distance from which another link can interfere with your receiver(s) is much longer than the useful distance of that link, and as the Omnitik has been placed to the highest spot on the site, it can see the remote interference sources well.
If the interference sources are other microwave links, you might be able to see them by running a background scan on the omnitik (the beacon signals are transmitted using robust modulation schemes so they omnitik should be able to decode their SSID even if their signal is weak). If its is something else, it may be a tough task to identify it.
In any case, any microwave equipment in a frequency band with no coordination will suffer from the same issue. Changing the channel will likely help, the question is for how long.
@Zacharias’s suggestion to use the 60 GHz band has several advantages - the band is not very populated yet, and the antennas are very directional despite small dimensions, and the signal degrades with distance very quickly so long-distance interference is much less of a problem. But the last two properties can also be seen as disadvantages - you cannot use an omnidirectional antenna as the antenna gain is a consequence of its directivity so with an omnidirectional antenna at one end, the link distance at 60 GHz would be just tens of meters.
Unless the logical topology and throughput requirements are against that, a chain (or several chains) of links may be a better choice than the star topology, as the neighboring locations may be able to see each other from lower heights. So you might be able to use the 5 GHz band.
Some of the links are from the previous system, we just replaced the old equipment with Mikrotiks.
I think it’s a lot messier than picture number two, but it worked until recently we added 20 more cameras and one Omnitik with two clients.
In that case the most likely cause is mutual interference between links. I don’t know how skilled you are so don’t take it personally. Can you add frequencies and channel widths used at each link to the picture?
row | link parameters | mutual position | actually occupied
| | in the frequency grid | frequency range
1 | 5320/20 eeeC | --ffeeeC | 5250-5330
2 | 5320/20 eC | --ff–eC | 5290-5330
3 | 5180/20 Ce | Ceff---- | 5170-5210
4 | 5200/20 eC | eCff---- | 5170-5210So I suppose the red link (row 3) to be affected by operation of the green link from the same site in almost opposite direction (row 4), as their basic (Control) channels do not use the same center frequency so they cannot coordinate because they do not receive each other’s control traffic. The radiation patterns of the antennas are not perfect, or there may be reflections from some metallic surface which are ubiquitous on the site, and the outer ends of both links probably can see each other directly. So by setting the same parameters for both, you might make them understand each other, but you still cannot be sure that those end stations (of each of these two links) which act as APs (and thus are responsible for traffic control) can “hear” each other - if they don’t, they won’t coordinate even if using the same frequency for the C channel. So I’d recommend to use a dedicated frequency range for each of these links by moving one of them to the free 40 MHz (the f letter in the table means a free 20 MHz slot), which would make them stop interfering with each other completely. Also bear in mind that even if they can coordinate, they will still share the 40 MHz bandwidth, so by giving each its own 20 MHz you’ll get higher summary throughput than when they have to fight for a common 40 MHz.
Regarding rows 1 and 2, the first thing I’m not sure about is whether row 2 really represents the yellow link from the same OmniTik which also participates in the green link (row 1). If yes, the interference (if it is interference) must come from somewhere else because the OmniTik is part (in the AP role) of both these links. So if it is the case, I would first reduce the row 1 link to just 40 MHz (5320/20 eC) and see whether doing so cures the drops. If it does, it makes sense to use eCee instead of eeeC, to occupy the 5330-5370 range instead of the 5250-5290 one.
Worse than that, you cannot be sure that the issues on both links have a common root cause. In radio environments operating in “free” bands, interference is always the first thing to look for (use /interface wireless scan wlanX background=yes), but an individual fault of a single device may ruin the whole link too.
Good afternoon, your question engaged me. Could you tell me what was your final choice as for the equipment and elaborate what exactly it is that your company does? Thanks!
I am in a situation that I am sure many have encountered here, out of money and not knowing how to make living till the end of the month. Now I keep on hearing both good and bad things about payday loans, and I have been reading really a lot about it, and my question is this: if I borrow now $150 and return it in 14 days instead of 30, will the fee paid be lower than if I return it later? Please help me to understand, I am real bad with accounting!
but I would like to learn more about RF because we started using more and more Mikrotik systems.