Re: Digitech AR-1733
Re airband activity at your location: Horowhenua is in NZ near Wellington yes? Suggest start here:
Start with the tower, even if the ground-air transmissions aren't audible you are close enough you may hear the air-ground traffic. If not that then air-ground on the approach frequencies should be audible.
You can match it up with ADS-B info displayed here as well:
Should get you started!