If you are looking at VNA equipment, make certain you have more than one unit in your plans for the following reasons:

1. If a unit goes down you still can operate at 1/2 efficency. If you have only one & it goes down - big problem.

2. Rental units are unlikely to be available from your local distibutor.

3. No other piece of equipment will work in an aisle set up around a VNA type machine.