Today's SAS article is:
Why isn’t full power available on my PAL Channels?
PAL Grants within a PAL Protection Area (PPA) are protected from interference from GAA users, but the SAS will still enact power restrictions if the SAS determines your PAL grants could cause interference to other high priority users. Even as a PAL holder, there are still incumbents and other high priority users that the SAS must protect from interference. These users could include:
- The PPAs of other CBSD operators in neighboring counties.
- FCC Whisper Zones
- The National Radio Quiet Zone (NRQZ)
- Experimental Radio Laboratories such as the Table Mountain facility in Colorado
If the power restrictions began only after CPAS (7 AM - 10 AM UTC) one day, it is likely that the cause of the issue is a neighboring PPA. From your perspective, it will look like a grant that had been working fine was suddenly terminated early in the morning. Just as the SAS must protect higher priority users from lower priority user interference, it must also protect higher priority users such as PPAs from interfering with each other. If the SAS determines that grants in PPAs owned by different CBSD operators might interfere with each other, it will enforce power restricts on both grants equally.
PPA protections only activate after a PAL holder’s CBSD has requested a PAL grant and held that grant through CPAS. PPAs can also grow as a PAL holder requests more PAL grants in close proximity to each other. As a result, a new or expanded PPA is far more likely to suddenly cause power restrictions than the other high priority users previously mentioned. This is because the bounds of the other kinds of high priority users are fixed and were taken into account when your grant was initially requested and approved.
It is recommended that you either request a spectrum inquiry or use the information Channel ranking in the SAS Portal to determine the most powerful grant the SAS can immediately authorize for transmission. If you desire a more powerful grant than what can be immediately authorized, we would recommend waiting until shortly before CPAS to request such a grant. This will minimize the amount of time your grant is suspended for IAP Pending, which will almost certainly happen if you request a grant with a higher max EIRP than the SAS suggests. The SAS has a much larger interference budget during CPAS, so it can authorize grants during CPAS that it could not have during the rest of the day. Once CPAS is over, the SAS will either authorize the new grant to transmit and the CBSD can resume normal operation, or the SAS will terminate the grant.
If the grant cannot be authorized to transmit even when the SAS has its full interference budget available, the SAS will instead terminate the grant and provide suggested alternate operating parameters in the termination message. These operating parameters will have the same frequencies as the terminated grant, however the suggested max EIRP will be the maximum that the SAS can safely authorize with its full interference budget. If you find that your CBSD is caught in a loop of requesting new grants and the new grants getting suspended until getting terminated, it is likely that your CBSD is not requesting grants that match what was suggested in the grant termination. This information can be checked by utilizing the CBSD’s History tab in the SAS Portal.
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