In most cases in Arizona you can tell if a repeater is open or closed by it's PL Tone.
Most 2 meter repeaters in Arizona are open systems.
Most open 2 meter repeaters use one of the following tones:
79.7
100.0
114.8
131.8
141.3
162.2
On the other hand, a large percentage of repeaters in the 440MHz (70Cm) band in Arizona are closed systems (private).
The standard PL tone for OPEN
440MHz repeaters in most of Arizona is 100.0 Hz.
In the White Mountains and some of Northern & North
Western AZ the standard PL tone is 110.9.
There are very few exceptions to this.
And likewise, there are very few closed repeaters in Arizona that do use 100.0
Hz or 110.9 Hz.
So, as you tune around the 440 band in Arizona, keep in
mind that if you can get into a repeater by using 100.0 Hz
or 110.9 Hz it is
probably an open system.
And if the tone is anything other than 100.0 Hz or
110.9Hz, consider
it CLOSED and don't use it without permission from it's
sponsor or licensee unless you see it published in a directory as open.