Transponder 'R' always on?

[MJKTuck]

I'm used to the 'R' of the transponder slowly pulsing as it is interrogated. Is it normal for it to be always on? Is that an ADS-B thing?

 

[RVDan]

It is normal in many areas, as all TCAS and some TAS equipped airplanes are pinging you along with ATC. ADSB has little impact since it transmits 1X every 1-2 seconds.