Hello everyone,
I am using 2 NetMetal 5 with 6 dBi omnidirectional antennas on both of them (3 antennas each). I am wondering is it possible to have connection (or signal strength better than -88dB ?!) with these antennas at 5 kilometer distance apart? It seems to me it is impossible even with clear line of sight. Maybe someone can help me configure something to have better connection. By the way Tx power is at maximum at all times and I need a minimum of 5 Mbps. Also I have to use omnidirectional antennas. Noise floor is extremely low since the setup will be used in outdoors maybe even rural areas.
I am using nv2 protocol and frequency mode is auto. How does channel width affect my connection? MCS is at lowest value possible since I need to receive data at ~ -88 dB. How does data rates option affect the throughput?

For a long range connection, don't use omnidirectional antennas!
Use directional antennas (parabolics) with a gain of about 25dB.
That will gain you 40dB of signal in this case.

Unfortunately I cannot use directional antennas since the transmitter and the receiver will be moving almost at all times. It is impossible to constantly track the position and rotate a parabolic antenna in the right direction. I started to think 6 dB antennas physically cannot connect to 5 km distance.

There is no way you get a stable connection over that distance with moving stations and likely also not always direct sight.

Thanks for help. Probably it won't work even with clear line of sight. I guess I have to change antennas somehow.

You can try sector antennas instead of omni. They are halfway between omni and directional w.r.t. gain.
With a sector antenna only the vertical orientation is important, it has to be very steady, but the horizontal angle can vary like +/- 50 degrees without much effect.

With a demand of only 5Mbps and rural position, what about 2.4GHz? Single pol omni antenna 12-15dbi and 11n 1x1? Even 11b will give 5Mbps.

Do you mean 802.11n by saying 11n? Sorry maybe I'm not very used to this forum.
The problem with high dBi omni antennas is they are way too long for my practice. They are usually >50cm. But I think at least for ground station 12-15d dBi antennas can be used.
What I really ask is with the setup I told before is it possible to have the connection? Maybe tweaking winbox configurations can provide 5Mbps @5km distance. For example I cannot find enough documentation about data rates.
timotei you told me 11n can provide 5Mbps why is it better than nv2 protocol? Should I use 802.11 protocols for outdoor applications?

There is nothing to tweak in winbox to overcome problems you have at the Radio Frequency layer! You need to solve them at that layer.

Antennas with more gain are larger by necessity and also always have directivity.
So when you see an "omnidirectional antenna with gain" it ALWAYS has a low beamwidth in the vertical plane.
That means it has to be mounted perfectly vertical. When it is slanted a little, it will quickly lose that gain and become even worse than a low-gain antenna.

From your description I guess that you are trying to communicate to a mobile device, and this has to be taken into account. When it can tilt due to terrain
or like a sailboat, it will not work with high-gain antennas unless they are kept aligned, just like a dish (but only in a single plane).

It looks like you simply are trying to do something that cannot be done with WiFi. Remember the power of WiFi is extremely low.
Other technologies like 4G use a lot more power and they can do it.

Other technologies like 4G use a lot more power and they can do it.

Just a tad of nitpicking: user's equipment in 4G operates at similar Tx powers as WiFi (max Tx power at around 20dBm) and also uses similarly shitty antennae (with gain around 0dBi) ... the difference is in the base stations: those transmit at higher power (can be higher than 30dBm just for reference signal which has similar use as beacon in WiFi, total power can be up to 46dBm per Tx chain), their Rx sensitivity is much better (to make bi-directional link somehow balanced) and almost always use high-gain antennae (at least 15dBi, up to 20 dBi sector antennae are frequently used).

And yet the usable range of LTE cells operating on higher frequency bands (2.6GHz, 3.5GHz) for usual mobile (moving) terminals is around 1-2km (usable in sense that users can get decent speeds in both directions, by decent I mean speeds around 10Mbps or more without any connectivity hiccups). And I haven't started to talk about possible interference problems.

I am new to Mikrotik, so others know better difference between nv2 and 802.11. You can use either, but nv2 is Mikrotik only.
My point was that 5Mbps is fairly low demand, so older systems might be OK. You need long distance, not high throughput. And for long distance, lower frequenzy (2.4GHz) is better than higher (5GHz). Units with 2.4GHz could be better for you, whether it is 802.11ac, 802.11n, 802.11g or even 802.11b. Your NetMetal5 is a good unit but it only supports 5GHz, and I think it will be difficult to reach 5km with two omnis in 5GHz. Again, others know better Mikrotik, but without personal experience I could suggest their Groove units or the BaseBox2 combined with as big 2.4GHz omni you can use. Do calculations first, and beware that high gain omnis have very little vertical opening. If 6dbi coverage represents a donut, 15dbi is a pancake - wider, but totally flat.
Let me add that you do not need to have identical antennas in both ends, if movement is restricted maybe a sector could be used in one end?

From what I understood changing the hardware is necessary. Trying 2.4 Ghz with 6 dBi omni antennas will be more useful(3 antennas on receiver and transmitter both).

What did you mean by calculating? Which calculator/equations can I use to gain insight about signal strength and bandwidth?

It really depends on the environment.
Please describe in more detail what you are trying to do.
The attenuation of a radio path in free space can be easily calculated by formula (from physics).
There also exists models to calculate attenuation in more practical cases, they even are available on some websites (for WiFi link planning).
But there are too many variables that are unknown for what you have described here.

I am using Friis equation to calculate received power.

2.4 Ghz is a good idea but the problem is modems at home is used around 2.4 Ghz so noise level might go up. Also can it provide 5 Mbps throughput at long distances? I will try them next week with Basebox 2. I don't have 2.4 Ghz compatible antenna right now.
Will post the outcome next week. Thanks everyone.

You have questions for "us" all the time, but you never answer a question asked to you.
Do you think that will work?

Calculation of link (simple registration required): https://mikrotik.com/calculator

Due to my company's restrictions I cannot answer every question sadly. I am doing it on purpose. I still think I gave reasonable amount of information.

I set up 2.4 Ghz Basebox2 with 6 dB omni antennas indoors. Noise floor is ~104 dB. Signal strength is ~-30 dB. Bandwidth tests show 30 Mbps data rate. Isn't it a bit low?

About setup:
I am using nv2 protocol and chose the least used frequency(auto gives the same data throughput). Channel width is 20/40 Mhz. Tx power is maxed out. Tried MCS 0 and MCS 23 but results don't change.

Now data rate is enough since I need 5-6 Mbps but can I maintain this data rate at long distances? (Considering that polarization is correct and noise floor is low).

I noticed that I have 2 antennas and I chose MCS 23 which needs 3 spatial streams meaning 3 antenna is needed (duh). I chose MCS 15 now data rate is up to ~80Mbps.

I will try this at long distances (up to 5 km outdoors.). I have to keep an eye on SNR value and according to SNR value choose the correct MCS value. Will post the results.