|AF:||Application for new station.|
|CC:||Call letters changed. Sometimes we learn of a call change a week or two before it actually happens.|
|CX:||License or permit canceled. Digits are the date on which it was canceled. (CX03 = canceled on the 3rd.)|
|GA:||New channel allocated.|
|LSR:||Live Sports Radio. Broadcasts to people attending a sporting event, these stations are not intended to reach anyone outside the stadium.|
|NS:||Permit granted for new station.|
|NW:||New station on the air.|
|OFF:||Station is temporarily off the air. (at least, they expect it's temporary. Sometimes this becomes permanent, resulting in a CX.)|
|PA:||Proposed allocation of new channel.|
|PC:||Coverage changed. (change in antenna height and/or power) PC> means increase in coverage; PC< means decrease in coverage; just PC means the change is negligible.|
|PG:||Granted change in coverage.|
|PR:||Requests change in coverage.|
|QG:||Frequency/channel change granted.|
|QR:||Frequency/channel change requested.|
|RA:||Station returned to the air after a period OFF:.|
|STA:||Special Temporary Authority -- permission to temporarily operate in a way not consistent with the license. Usually for reduced power after equipment failure.|
|XG:||Granted change in site.|
|XR:||Requests change in site.|
Call letters shown in parenthesis are the "primary" station relayed by the station whose parameters are shown.
It's common for more than one change to happen at the same time -- for a station to change frequency and increase power simultaneously, or to increase power at a new site, or do all three. An application that involves multiple types of change will be listed under the type that's most likely to affect reception. Frequency/channel change first; then change in site; then change in power/tower height.
In the USA, most stations must operate on a channel "allocated" to the community the station will serve. PA is a proposed allocation. If the FCC grants it, we have a GA - granted allocation.
After an auction is held to determine who gets to use that allocation, the successful bidder must file an application for construction permit. (AF) Assuming everything on the application is consistent with the regulations, the FCC will grant that construction permit. (NS) The construction permit gives its holder three years to complete construction.
In most cases the station may begin operating as soon as construction is complete. It must file for a "license to cover" within ten days, at which point it becomes a "new station on the air". (NW)
(AM stations, non-commercial FM stations, and low-power TV stations may choose any channel/frequency they can show won't interfere with anything else. An auction may still happen if more than one AM/LPTV applicant chooses the same non-interfering channel - i.e., that they won't interfere with any existing facility but would interfere with each other.)
If a station will be off the air for more than ten days, it must notify the FCC. After thirty days, Special Temporary Authority must be obtained. Either situation results in an OFF listing.
Once the station returns to operation, you'll see an RAentry here. On occasion a station will permanently cease operations. This is listed as CX. Sometimes this cancellation is at the request of the licensee -- in other cases, it's imposed by the Commission.
A construction permit must also be sought if an existing station wishes to change technical facilities. This may be a PR if the station wishes to change power and/or antenna height; a QR if it wishes to change channel/frequency; or a XR if it wishes to change site. Presuming the FCC grants the request, it becomes a PG, QG, or XG. And when construction is complete, it becomes PC, QC, or XC.
Sometimes, a transmitter failure, or tower collapse, or some other event will leave a station in operation, but at less than full authorized facilities. This requires a STA, or Special Temporary Authority.
The terminology is different in Canada but the process is similar.