Unique problem. (perhaps)

[Alan booker]

I picked up a used HL tiger for a bargain price because it has no transmitter but that's OK because I only want to build a display model.
However, I have spare transmitters laying around and wondered if there was a way of figuring out the wavelength of the RX board fitted to the tank.
It doesn't have a crystal I can swap out like most of my other R/C stuff, but if I knew the wavelength, I guess I could buy the appropriate TX crystal.
Any ideas?

[HERMAN BIX]

G'day Mr Booker.
I will move this to general questions, but would ask you to go to the introductions section to give us a bit of an insight into your relationship with the hobby & a broad geographical idea of your location so we know where best to direct advice.