This will probably be your best strategy if you want to hear when the shared news chopper is taking live shots for one of the local TV stations.
Use a flight tracking app to get alert for whenever N321PD takes off from the Garland/DFW Heloplex (Monday through Friday). Sometimes there’s an app alert delay of 5-10 minutes.
Scan for these
four chopper frequencies:
450.3125 - CH 04 FOX
450.1125 - CH 05 NBC
450.0875 - CH 08 WFAA
450.5125 - CH 11 CBS
The pilot will make contact with someone from each one of the stations about how they want to proceed. Sometimes a trip will be a no-go from the start if there's some sort of flight restriction involved (i.e. low ceilings from heavy fog).
On average, the recorded coverage is edited down to several seconds when the public sees them broadcast on TV unless there is some sort of major news and you get to see continuous live footage. For example, if there was a noteworthy wreck on a small street you might see up to 5-10 seconds of recorded footage on one of the newscasts. In another example, if there’s a police involved shooting or incident you might see several minutes of live footage from the chopper.
Sometimes the person at the TV station will say something along the lines of we can go live in 2-3 minutes or something like we can go live after the next commercial break.
The chopper will orbit (fly around in circles) around a scene while it acquires any sort of footage and you can track the flight path on a flight tracking app or website.
Once the footage has been acquired the pilot will ask each of the stations if they need anything else before returning to Garland. Sometimes the pilot will get footage for one station on a side trip on the way back.