So I think I just learned the hard way (after smoking a Stridsberg multicoupler) that my XPR 4550's are sending RF of some sort when changing cap+ sites. It's just a little blip of rf wattage on my cheapo watt meter but enough to register.
Any idea what the radio is doing? I assumed short of a CON+ system there wouldnt be any affiliation packets so I thought I was safe.
I'm taking this to mean you have a Linked Capacity Plus site? Otherwise, it is a single site, not sites.
Either way, yes, the radios send a brief burst of data when they turn on. Neither Capacity Plus nor Linked Capacity Plus have a "controller" in the standard way we are used to. PassPort, Connect Plus and other systems use a controller but all the controlling in CP systems is handle by the repeater(s).
I doubt that your meter would react fast enough to measure the wattage and, when measuring output of a subscriber with a standard watt meter, it is going to be inaccurate. The subscribers switch on and off rapidly. I find that when using an analog watt meter and measuring the output of a 40 watt mobile, it will typically read 15-18 watts. Putting the subscriber on an R8000B, which can measure MotoTRBO output will give you an accurate reading, but intermittently. (hard to explain).
ARS is a setting that will tell the radio to register with, usually, a third party application (text/mail server, GPS, dispatch console, etc). That will result in a little more activity when you turn a subscriber on.