[ARC5] Trade ATA for ARC-5 Stuff

[Mike Morrow]

Dennis wrote:

>I need the following ARC-5 pieces:
>
>MD-7 modulator (I have a dynamotor)
>C-29 Control Box

The C-29/ARC-5 MF/HF transmitter control box is very difficult to find.  The equivalent ATA and SCR-274-N control boxes can not be be used interchangably with the C-29 because the 18-pin connector on those boxes is slightly different from that on the C-29.  The C-30 and C-30A VHF and MF/HF transmitter control box seems most common.

>RE-2 Antenna relay unit and mounting plate
>C24 Local Control Units (3)

RE-2 units are fairly common, but the shock mount MT-77/ARC-5 is not.

All individual receiver control boxes for the AN/ARC-5 are also darned hard to find, whether it be the single receiver remote tunable box (C-26/ARC-5), the fixed-tuned receiver audio control box (C-27/ARC-5), or the local control box panel you seek (C-24/ARC-5).  If you use the local control panel, then you need a eight-pin plug for each receiver at the back of the receiver rack MT-65/ARC-5.  A MX-2/ARR-2 plug/jumper assembly can be made to work.  It seems to me as if the WWII receiver remote control panel C-125/ARC-5 is easier to find, but that panel does not have a power ON-OFF or CW select capability such as the C-24 and C-26 have.  The C-38 three-receiver VHF and MF/HF audio and AN/ARR-2 control box seems to most common.

>A pair of the 18 pin 6962 connectors or the open wire equivalent 9585.
> (MD-7 to C-29)
>One 12 pin 9377 or equiv. 9589.   (MD-7 to Xmtrs) 

These two are among the hardest of all A.R.C. plugs to locate.  They have a slightly different pin arrangement on a couple of pins, compared to the much more common ATA and SCR-274-N 12- and 18-pin plugs.

Unless you were going to plug in the headphones and microphone directly at the rack and/or MD-7, you'll need a J-16 or J-22/ARC-5 audio jack box, which connects to the MD-7 through another scarce pair of plugs, the A.R.C. type 9821 8-pin plug.  The control boxes for the AN/ARC-5 gear do not contain audio jacks like their ARA/ATA and SCR-274-N equivalents do.

There's a 30-MByte .pdf of the LF/MF/HF AN/ARC-5 service manual available for download at:

http://bama.edebris.com/manuals/military-kg7bz/arc5/

Figure 8-55 shows various typical installations of AN/ARC-5 equipment, including combos with the AN/ART-13, the ARB, the AN/ARC-4, the VHF AN/ARC-5, the AN/ARR-2 homing set, etc.

Fig. 8-55 sheet 2 shows a MF/HF system, all AN/ARC-5.  But I think such installations must have been very un-typical, hence the rarity today of AN/ARC-5 control boxes except for the C-30(*), C-38, and C-125 variants.

An interesting set, one which I've completed except for four plugs, is the system shown on Fig. 8-55 sheets 5 and 6.  This set is listed as a single place fighter installation in the AN/ARC-5 operation manual.  It consists of a three-receiver rack containing the R-4A/ARR-2 homing receiver, one fixed-tuned MF/HF communications receiver (R-25, -26, or -27), and the four-channel VHF R-28/ARC-5 receiver.  The two-transmitter rack contains the four channel VHF T-23/ARC-5 and one MF/HF communications transmitter (T-18, -19, -20, -21, or -22) that matches the frequency of the MF/HF receiver.  The control box for all the receivers is one C-38/ARC-5 control box, which operates the R-4A/ARR-2, and has audio-only controls for the fixed-tuned VHF and MF/HF receivers.  The control box for the transmitters is a C-30A/ARC-5, which selects the VHF channel for the R-28 and T-23, and allows selecting the MF/HF transmitter.

I like this system because all three major variants (Homing, MF/HF, VHF) receivers and both major variants (MF/HF, VHF) transmitters that were used in the AN/ARC-5 system are all present.  It's an example of an early integrated avionics system.   I also believe that this type of system was far more likely than any three-receiver, two-transmitter MF/HF-only AN/ARC-5 installation.

Good luck in your searches.  A SCR-274-N set is far far easier to complete.  Some of what you seek will not be easy to find, nor inexpensive if found on ebay.  It took me years to get where I am with mine, and I've still got a few small items to find.  If it hadn't been for the help of a couple of list members, I'd be still missing many other vital components.

Mike / KK5F