5.8 GHz Elevated Devices Maximum EIRP in the United States
In the United States there are some devices that when elevated to ePMP may have a maximum EIRP in 5.8 GHz of 41 dBm for 20 / 10 / 5 MHz channels and 38 dBm for 40 MHz channels. Previously, the devices may have run at unlimited EIRP with their non-elevated software. This could cause a decrease in EIRP for elevated devices at longer distances from the AP and could cause UL throughput to be decreased.
The reason for this is certain devices made prior to June 2016 were originally given a grant of unlimited EIRP as long as other bands were not used (i.e. 5.1, 5.2, and 5.4). In June 2016 another grant was provided that limited EIRP to 41 dBm (20 / 10 / 5 MHz) and 38 dBm (40 MHz) while granting use to these other bands. The end user can choose to follow the older rules if they like on the non-elevated software. ePMP applies the latest grant to these devices and hence uses the lower EIRP.
Please share this information amongst yourselves in the WISP and PMP communities and discuss ways to optimally address this issue.