Odd Spectrum Spikes on c5c w/30dbi rocketdish

Hey there fellas,

I’m getting some off unexplained spectrum spikes all across a previously clean spectrum on a CPE that has a dodgy connection. The huge spikes change frequency and location very rapidly, and a colleague of mine has suggested it might be wave scattering.

Could this be a symptom of a bad setup, or just a noisy connection? The CPE has issues with upload speed, but the download stream is relatively stable.

Here is a snapshot of the local spectrum

The equipment is a Mimosa C5c with a 30dbi rocketdish.

Feels to me like there could be an issue with the radio, possibly the cabling.

Occasionally I have seen some spikes like your picture, but normally that is from noise the radio is only intermittently picking up.

What firmware are you running?

Hey William5,

Thanks for your insight. Our c5c’s are running the C5 2.5.2 firmware version.

A colleague of mine did some investigation and says that the Access Point is having difficulty hearing the CPE(Client to A5 channel), but the client can hear the tower just fine.

Well, I would check the alignment make sure there isn’t anything funky going on there.

Double check that both AP and Client have the same TX power settings.

Hey William,

Thanks for your input. I’ve done some deeper investigation and found that all of our CPEs are having odd spectrums that did not report these major spikes a week ago. However, we are running in Wifi-interop mode so it may be self-interference. I would assume the noise would be on the same channel and not all over the place, though.

Here is another spectrum graph from one of the other CPE radios. The spikes were not there about a week ago.

The spikes feel like there is some sort of issue with the radio measuring noise and the measurement being done while the radio is listening to your AP.

I would bring it up with Mimosa Support. Could be some performance being lost there… If you go to support.mimosa.co you will see a “Chat with us” button, those guys should get you some answers.