I haven't tried white tape over the sensor for plasma, however I do find it to be very effective with florescent electronic ballast lighting. Without the tape, the sensor is totally saturated by the lights. Range is usually reduced to about 15 feet.

The Xantech standard 480-00 with a piece of tape is compatible with a wider range of equipment than the CFL-friendly 480-80.

We also use the 490 with a piece of white tape quite often with very good results.

Xantech offers filters as one of their products (the Sun 480 and the Sun 490). The white tape seems easier to put on and is about $4.99 less expensive.

Give it a try the next time you have to do a dentist office.

Keith