5.9GHz Frequency Selection

Hello – our interest in Mimosa wireless products was already high based on field reports from fellow WISP operators. Thus far, we are pleased with the test results, which compare very favorably to our existing wireless outside plant – UBNT.

Your support for the extended spectrum in 5.9GHz and above made us VERY interested. We have a STA from FCC authorizing us to use 5855 to 5925 - a 70MHz chunk.

Frequency selection in the AP must assume that we’d be using 80MHz channel, because the highest freq we can select is 5885 - effectively locking us out of 30MHz of usable frequency space, because we ONLY use 20MHz channels. We find that if we keep our path lengths AP - CPE reasonable, RSSI and SNR high (thank you RF Elements Asym Horns!) in a 20MHz channel we can support 100Mb/10Mb plans all day long, and re-use is great. With 40MHz or larger channels, not so much…downlink is robust - 170Mb or better, uplink falls apart due to RFI / noise issues. So 20MHz is an easy choice to live with.

Is it possible that your devs could build a little more intelligence into the frequency select function on the AP, and gate the selected frequency based on channel size selected, not simply ASSUME that 80MHz operation is going to fly? In our market, with 4 or so competitive WISPs, I can assure you that 80MHz channels are very ineffective. A waste of spectrum, and a blight on the RF landscape.

Any feedback greatly appreciated.


Drew M Mooney
South Valley Internet, Inc.

This would be an @DustinS or @Jaime question I think.

Hi @Drew1

The FCC STA only allows from 5850 to 5895, even though the band goes to 5925. This has been a common misconception for some of the STA users. So if you’re using a 20MHz channel, the highest you can select is 5885 (capping out at 5895).



Interesting. Generally when a license specifies a range…

An STA only last six months; then it needs to be renewed. The FCC last year, after issuing STAs, released its Order on U-NII-4. They decided to reserve 5895-5925 for vehicular use, C-V2X, while 5850-5895 was opened up for indoor use only, except via the STA process. There is still an open docket on how to open it to outdoor use without an STA; we’re “on the case” at WISPA. But I don’t think new STAs will go above 5895.
FWIW a key issue is that there is a lot of federal radar on 5850-5895, and limiting it to indoor use limits the risk. Outdoor use is likely to only be allowed in places where the STAs are able to be issued. So the PtP devices and APs are likely to need GPS. That of course is no problem for Mimosa, which already uses GPS to phone home and automatically protect TDWR.

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Thanks for the info!