What is it? You can get them from DPA directly, but it must be a standard part. No one on the intergooglewebs seems to know. I could use a pair of the female panel mount variety, and it'd be dandy if Mouser/etc carried it. Might one of these be they?
http://www.fairviewmicrowave.com/coaxial_connectors.htm?gclid=CP6r5dTXi68CFQjd4Aod_1g9Mg
http://www.fairviewmicrowave.com/coaxial_connectors.htm?gclid=CP6r5dTXi68CFQjd4Aod_1g9Mg