I want to set up a link of 34 Kms with maximum bandwith possible

I am thinking for use Mimosa C5c with the RF Elements UltraDish TP 550 antenna. It seems to me, using the Link Calculator of RFE, that I can get a good link, but I am not sure about how much theoretical bandwidth I must wait.
Between point A and point B there are almost 34 Kms.
The noise in A is about -90 dBi and Point B is some noisy (about -85 dBi).
The heigh at point A is about 18 meters and point B is about 15 meters.
Point A location is: 10.484441, -66.785971 and Point B location is: 10.480608, -66.482267
I need to get for this link at least about 40 Mbps downstream plus 40 Mbps upstream (about 80 Mbps aggregated).

My country is Venezuela and I don’t know if I can get the maximum output power of 27 dBi of Mimosa C5c for my country. And the antenna Gain is 27 dBi.

Do you think I am Ok with my design? What am I missing here?

Hi @Luis_David,

While I think you would be ok as long as you’re using clean channels, it might be good for you to put this in our design tool. You can choose C5c and under settings change the antenna gain to 27dBi to see if this would work ok for you.


Hi DustinS, Thank for your answer.

Do you know if I can reach 27 dBi maximum output power for my country, Venezuela?

If you use Venezuela Licensed mode, you should be able to reach the max TX power of 27dBm output power

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Hi there, I finally used a Ubiquiti Dish of 34 dBi with Mimosa C5c and works pretty well with this 34 Kms… I can get about 100 Mbps of aggregate bandwidth.
I can not get 27 dBm from Mimosa C5c using Venezuela Licensed, I just get until 24 dBm.
Works great after the link is up.

Hi Luis. In 2.5.1 we changed showing total output power to transmit power per port. So if you set your C5c to 24dBm, it will be transmitting at 27dBm total power.

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the real output power per chain is 24dBm ? and if it sum add 3 dBm , but not real …?

It’s how MIMO works, I believe, because you technically have 2 outputs the standard for measuring the total output is adding them together (because your total EIRP is the total output of the radio) so 24 dBm is actually 3 dB higher in total output.

You may be loosing a little bit of RX power at the other end, but you gain that or more back in the stronger ability to decode the data from the noise.

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ok thanks , and i saw an 4W amplifier for drones in Aliexpress , you think works to put between c5c and parabolic antenna ? i think its gain 8 /10 db … it´s only for testing of course.

Uh huh… Right. If you are in the United States, you need a special license to do wireless testing/run higher powered gear. If you are elsewhere in the world, I don’t know the regulations, but you should follow them. I doubt there are many places in the world that Mimosa radios can’t meet or exceed the legal limits for EIRP (Total output power) so, unless you live in one of those places you will be breaking the law.

Also, I would recommend against it for technical reasons as well. Most amplifiers can introduce noise and/or distort the signal which while it may improve the received signal, will degrade the MCS you are able to reach. Modern radios use several different types of modulation to achieve the bandwidth they are passing. While Amplitude and Frequency modulation are able to be amplified fairly easily, Phase Shift and the other digital modulations can be severely effected by a poor amplifier. Thereby decreasing the total amount of throughput you can actually achieve.

If you want a better signal, check your alignments. If you alignments are good and you still want a better signal, get a bigger antenna. More gain in your antenna will get you farther then introducing hardware that the radio was not designed to work with.

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Hello Mr @DustinS dustin
i have c5c link connected to a mikrotik mant 30pa dishes at a 2 km distance please can u tell me what should i choose local and remote antenna gain and channel width and tx power in order to pull out max megabits of my c5c thanks in advanced
And please tell me wat is considered higher negative or positive values in antenna gain and tx power

Positive values are always higher then negative values, both in Antenna gain and TX Power.

Depending on your location and choice of frequency in use, the rules vary. That said, your C5c should be programmed with the legal limits for the frequency you are using and the location you are in. All you have to do is set the correct antenna gain and your C5c will use the maximum output power (if necessary) allowable. (If you are using Auto Power, in the Channel and Power Settings page)

Thnx for the reply in case of 2 to 3 km distance between the links what values do i choose for antena gain local and remote and tx power negative or positive values??

Well, if you have your gain set correctly, I normally use the minimal TX power I can (to decrease the overall noise I am making) that will still leave the link useful.

at 2-3 km of distance, you shouldn’t need very much power to get a really good signal 3-5 dB should be significantly more then enough. If you are having issues I would check your alignment and look up some of the posts here and online about aligning dish antennas.

I have a problem first of all almost all of the frequencies are restricted but i managed to choose a clear one i have the latest firmware update for c5c secondly when i choose antenna gain 15db the tx power gives me max 4 dbm and when i lower gain to 5 db i get tx power 23db kn both cases i coudnt manage to pull more than 150 mbps and the distance is only 2.7km please help

What you are doing is tricking the radio into thinking it has a lower gain antenna then it actually does, this is illegal (for most of the spectrum in FCC land, other places it may be different)

If your alignment is good, then you should be able to get a -51 dB signal on a 20 MHz wide channel with 4 dB of output power using the antennas you are talking about, a bit less for wider channels. Depending on your environment (noise) that should be plenty to get a good SNR.

Here a video about aligning antennas

If you want further help, I would recommend posting your Channel & Power Page as well as your Main Dashboard (feel free to mask any personal information if you would like).

Thnx a alot for ur help. I tried nearly all values.still nothing good anyways if i want to align using aim mode what gains should i use for my fine tuning? and sure i will post my dashboard and chsnnel powers that iam using

Since you are already connected, I would use your lowest output power you can. That will minimize the chance that you will align on a side lobe. Sometimes it’s useful to use a higher TX power to figure out where you need to be generally, but when you are doing fine tuning alignment it is FAR better to have a weak signal to work with because the side lobes will be less easy to get yourself stuck on.

Once you have gone through alignment of both sides and you are confident you are lined up, I would set the dB gain of your antenna properly in you C5c then turn up the power, being in the low 50’s should be good enough for most links. If you are in a high noise environment it may be that 5 GHz might not be appropriate for your application. That said, Mimosa has some videos of C5cs being used in high noise environments and still pushing pretty good bandwidth.