a week ago
Who is telling you this, a coordinator? We have been completely approved for all channel sizes by the FCC. As long as you are not designing your link to run at QPSK under nominal conditions it is fine. QPSK is just used during "events" in order to prevent the link from dropping. The rules were written way back in the day when radios didn't do auto-negotiation of constellations so we hear this from time to time...
Who is your coordinator?
a week ago
Reaching out to you regards the concern from this coordinator. Can you email me and we can work through whats going on.
In all reality if they are just coordinating for QPSK they shouldn't but at higher modulations are within FCC specifications. Exactly what @UBNT-Gary stated. We have had TONS of links coordinated and are still going strong. So lets discuss what is going on. Thanks!
a week ago - last edited a week ago
Yeah, this nonsense is based on a spectral efficiency requirement to prevent links that wasted spectrum with poor performance.
If you configured the radio to limit modulation to QPSK only, you would be in violation of this rule. Or of you somehow did a 400 mile link with small antennas and then also mis-aimed them to the point that only QPSK was possible you would be in violations. But no one is going to do either of those.
With the AF11FX, QPSK is ONLY used very temporarily during rain events when higher modulations are not possible. The temporary use of QPSK in these situations is totally acceptable.
The coordinator is not getting it. Find another coordinator.