FM Bite/Audio Interface (GRC-206)

© Brooke Clarke 2010

The early versions of the GRC-206 system used either the RT-246 or RT-524 low band FM tactical radios.  This box came as part of the MT-6250 equipment rack.  Its purpose is:

• Built In Test Equipment (BITE) related to the antenna connection (the Tx and Rx antenna signals go through this box
• Interface the KY-57 with the X-mode of the FM radio
• Allow the C-11169 Signal Distribution Unit SDU to select the channel on the RT-246 radio
  

When the GRC-206 was upgraded to use the SINCGARS radios (RT-1439, RT-1523) this box was removed and as far as I can tell was not replaced so the SINCGARS radios need to be manually operated from the front panel rather than from the C-11166 Universal Remote System Control  URSC.  This seems strange since it would be possible to make an interface box that allowed full remote control of the SINCGARS radios.  If you know more about this please let me know.

contract: F04606-89-D-0110-0001
p/n:        812132-801
s/n:        AA0066
Mfr:       37695 Magnavox, Ft. Wayne, IND, U.S.

Mounting Plate
p/n: 37695-939265-801

Internal Cable Table

2x15	Wire	Func	J3 SDU	J4 VHF FM (REMOTE)	J5 KY-57
1 = 16	Gry CCC			B (Ch 2)
2 = 17	Vio CCC			D (Ch 4)
3 = 18	Wht CCC			C (Ch 3)
4	nc	TP2	nc	nc	nc
5	Wht/Blu		B
6	Wht/Blk				A
7	Wht/Brn				B
8	Blu CCC			E (CH 5)
9	Grn CCC				G
10	Yel CCC			F (Ch 6)
11	Red CCC			H (Ch 7) (or K CH 9?)
12 = 27	Wht/Vio			A (CH 1)
13	Blk	Gnd		L (CH 10)
14	Brn CCC			G (Spare ?)
15	Org		D
16	Red				H
17	Wht CCC				C
18	Gry CCC				D
19	Blu CCC				F
20	Org CCC			J (Ch 8)
21	Grn CCC			H (Ch 7) (or K Ch 9?)
22	Vio CCC				E
23	Blk	Gnd	A
24	Blk	Gnd	E
25	Wht/Yel			M (+25.5 VDC Switched)
26	Blk				K
27	Yel				J
28	nc		nc	nc	nc
29	nc	TP1	nc	nc	nc
30	Wht/Red		C

CCC = Coax Center Conductor

available from Tony Snider