Satellite phone antenna mounting

Has anybody here done that?

I am looking at installing one on a TB20. This is likely to be Iridium
or Thuaraya (Europe) and I believe the antenna is a dual one, with a
GPS receiver also.

I am trying to find one which comes with some kind of approved data
regards non-interference with other L-band (e.g. GPS, DME) antennae,
so I can avoid the DER issue.

Thank you for any pointers.