how can I monitor Time Capsule

Fan noise? this noise is the disk in the TC, is Time Machine running and backing up to the TC, or do you use another disk for TimeMachine? Open Time Machine Preferences and you see what it is doing. In the Finder you can see how much free space there is on the TC (getinfo on TC).

The light Amber or Green is the Router/WiFi activity, it should be constant green.

What OS version you have running? How old is the TC (which generation, run Airport Utility to see that, rightclick on the icon of the TC).

If you enabled the "feature" to have the indicator lamp blink green on activity, then that lamp will act like the activity light on a modem....it will blink almost constantly when you have the computer on.

Most of us do not want to watch the light blink and opt to have it stay a solid green....the default setting..... when the Time Capsule is on or backing up.

The noise that you hear is likely the hard drive spinning up and spinning down. The fan does not normally run unless the Time Capsule is very hot.

Time Machine Buddy is a useful Dashboard application to get an idea of what is going on with the Time Capsule. You might want to give it a try.

Apple - Downloads - Dashboard Widgets - Time Machine Buddy

If you want a complete history of exactly what is backed up on each pass of Time Machine, you might want to take a look at BackupLoupe.

soma-zone: BackupLoupe

Unfortunately, Apple will not let you do this, since Mountain Lion will not allow the previous version of AirPort Utility 5.6 for Lion to be "officially" installed.

However, if you have a previous backup of AirPort Utility 5.6, you will likely be able to "restore" it to the desktop, then simply copy it over to your Applications / Utilities folder. You can run both AirPort Utility 6.x and 5.6 on your Mac.

Or, if you have another Mac there, you can copy the AirPort Utility 5.6 application over manually.

Third option is use a utility like Pacifist to manually extract the 5.6 application from the download package and then you can manually place it in the Applications / Utilities folder.