Who makes this part, please?

Somebody else might know, what's a 'FEM'?
What's the package style?
I'm assuming you don't see a mfgr logo on it?
A picture might help, if you can do one.
The more info we've got, the possibility of ID becomes more likely.

 

Front-End Module.

http://en.m.wikipedia.org/wiki/RF_front_end

 

Stevenotts, do you just have the module, or do you know what it came out of? (The manufacturer of the rig?)
Is it foreign or domestic?
Anything you know that we don't, might help.
It's possible the QA1 124 is just some designator they use in the factory when they're
assembling the finished product. It might have another number engraved or taped to it that might give more useful information for identity purposes.

 

It's probably a custom made part for that rig..
I'd try ebay for a cheap model, and try to salvage parts from it.
Or you can try to get help from the radio manufactuer.