C5 Bandwidth Issue

Hey guys hope all is well,
I am having a bit off issue with a couple C5 link which I work with, they span over a variety of mile (eg. 17 miles, 10 miles etc), however I am having some issue having them passing a standard bandwidth of 150/150.

I always spend time to choose the best possible location for functioning frequency on the spectrum analyzer, having link aligned to best and lowest signal one can get and also based on that I also see and choose fit what channel width to have the radio operating in.
Any suggestions as to how I approach this matter?

Thanks in advance.

A. Brown.

Could you post a screen shot of one of your links and it’s Dashboard page, as well as a screen shot of the Channel and Power page?

Other information regarding the link might be useful and what you are trying to do with it.

Okay no problem will do so and add.

So the links I work with are used to connect Sites, a network system connecting sites which in return issue connection to internet customers/clients connected to the site which we send internet to using these Back Haul devices.

Cool. Is there anything obstructing the link? Are you actually using a 34 dB antenna?

No, antennas are places at highest point on towers, may I also mention that these towers are situated in hilly or mountainous areas so completely no obstructions whatsoever, and no I am not using a 34dB antenna I or we are mostly using a 2ft dish in most cases.

Do you know the gain of those antennas?

Actually I don’t, and I am sure that would have been of help to help you analyze but I don’t at the moment.

It’s not that big of a deal, it just helps me to model them, probably they are around 24 dBi (that’s pretty common for 5 GHz and 2 ft Dish antennas)

If that is the case, there isn’t a whole lot to do, you are getting as good of a link as is possible (at least according to Mimosa’s design tool.) Which I have to commend you for, such long links are very hard to align and setup.

The issue (at least with this link) is that you are shooting so far the RF energy is becoming so dissipated that there just isn’t enough difference between the signal and the background noise for the radio to be able to tell the difference between what is information in the signal and what is just noise. So the radios have to talk slower (lower modulations) to be able to be heard.

It’s kinda like you and a friend are on opposite ends of a baseball field, when things are really calm you can hear each other pretty easily, but as you get further apart you have to speak louder to be understood, eventually you have to cup your hand around your mouth and talk very loud and slowly so that the other person can understand you.

The cupping of your hands is like the dish, if you get bigger hands you can focus your voice more and be better understood from further away.

So, where I would start with this link: bigger antennas. I would look for something in the 30 dB range. RF Elements makes excellent antennas, and probably their TP-550 (~27dB) would work out well for you (I would get a Twist Port version that way you can minimize your signal loss in cabling). RF Elements is probably the most expensive option I would consider, they make very high quality stuff and their support can’t be beat.

If your curious RF Elements has a pretty darn good video series on YouTube about RF antenna design and how they work, admittedly promoting their own stuff a bit, but it’s overall value is very educational and not just a bunch of advertisements.

Thank you so much, I understand all that is said very clear. I really appreciate the time out and effort to respond to the issue I am facing, really appreciate it. I definitely will take into consideration and put into practice the information given, also I will definitely watch these videos you advise of watching.

Thanks man.
All the best.

Another thing before you go, what is the maximum distance you recommend across a link using these devices (mimosa c5)?

Also I just did some background checks with techs and inventory about the equipments used in installing these links, we have mainly or about 95% of our set up using 3ft dishes.

It really depends on the quality of the antenna and the gain of your antenna.

Theoretically, somewhere in the 200 km range there would be some sort of issues with timing. Maybe, I am not 100% on Mimosa’s PTP protocol.

That said, I would be looking at a B5c over the C5c beyond a Mile or two (1.6 km to 3.2 km), but then again, I have a somewhat unique situation of having only Mimosa equipment for a large portion of my network and I mostly only need to deal with noise from my own network. The GPS sync and other features of the B5c really become attractive to me more quickly then for other people. I am only using C5c for PTP links under 1 km. (Special customer links and one short link between two of my tower locations)

So it really depends on the requirements of the link, if I don’t need to GPS sync my radios and I just need something really cheap, I could probably convince myself to push a link out to the 10 mile mark (16 km), maybe further depending on the situation. It’s just that my situation really has requirements that make the C5c not all that useful to me in most of my PTP links.

Okay I understand, I thank you once more, from this I do believe I have a few things to think about and further assess moving forward. Once again I really do appreciate your time and sharing of knowledge.

Thanks you.

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