Does anyone else have a problem with jamming/reduced range when the DTS-1 is functioning ?

We race on a wide open 4 acre area with a paved road, with a variety of radios (traxxas, airtronics, dhk, futaba, etc).

Normally most of the radios have at least 1/4 mile range, but when we are using the xmas tree, everyone's range is significantly reduced to around 180 to 200 feet !

Is this normal ?