Juliet 637; I presume this fighter is using his tailnumber as his callsign. In that case this is a F16 from 312 Sqn., Volkel NL (EHVK). Working with CRC Nieuw Milligen NL (EHMC) on 258.0000 MHz (bandbox).
Also heard Alpha Golf 01 & 02 working on this frequency. These are also F16's from Volkel Airbase, The Netherlands.
A/A comms on 138.5250 MHz.