[Milsurplus] Questions on RA-1

[Hue Miller]

Question on Bendix RA-1: I know the "official" matchup
transmitter was the 2J24 transmitter, but i'd like to know
what a reasonably realistic matching transmitter might be.

Also, i have asked this some time back, but quite forgotten
the reply. What does this mean, on the RA-1:
"Modified for Postion 2 Working"
What aircraft would have a second receiver position? 
Tnx-  Hue Miller