It's probably "dry" N2. It is used to prevent water absorbtion and O2
absorbtion of the RF. It can also be used to detect leaks and to keep
out atmospheric water.

Russ

On 11 Jun 2004 07:32:17 -0700, (David Harper)
wrote:

I'm working on a project that involves antennas that appear to be
pressurized with nitrogren (approx 10psi). What purpose does this
serve? Does it help with transmission properties, gain, etc? It is
used on an aircraft, if that is a factor.

Thanks in advance!
Dave