5-H Field Standby Assignments

5-H-1 When a Pilot is called to the airport on a standby basis without a specified Flight assignment, his Duty Period shall begin at the time he is scheduled to report or actually reports, whichever is later.

There are 66 references to Field Standby in the UPA, some of which mention the "airport" in the same sentence. So, I'm gonna go out on a limb here and say that "field" means at the airport. The report time is defined above. Other than that, I could not find a clear definition. That's not a bad thing. The lack of a clear definition used to apply to a short call as well, but people pushed the envelope, and now that's not the case. As far as pay...we are payed 73 hours to sit reserve and comply with the contract.
In Den, there is a sign in sheet. I personally dress, pack, and ride the Airside bus to OPS so that I sign in at report time. Then I shoot the sheet/watch TV/do CQT/drink coffee for 4 hours until my time is up. The intent is to recover the operation from a real time hiccup. Personally, i'd rather do the above then sit in my car in the parking lot, but that's just me.