Hi Mike,
The bulkhead connector is from Centric RF, part number C3614. It is considered a precision type-N connector. Particularly good VSWR. Data sheet link below. It is spec’d to 18GHz and in our tests fine up to 20GHz. The main reason for using the type-N was due to customer feedback, mainly revolving around robustness, rigidity, and prevalence in labs.
http://centricrf.com/content/pdf/C3614.pdf
Let us know if you have additional questions.
Regards
