Hi Mike

Thanks for your comments -- and I think we've discussed this issue in the past!  Your comment "(It has the added advantage in our generation of eliminating half of the now scarce connectors you need to assemble the entire set.) " is very astute.   My 183 components are boxed up and I think I have enough connectors for the various pieces, but not for a "real" junction box.

I was looking at the schematics of the 183 yesterday to see how involved it would be to build the junction box.   It looks straight-forward, but will take time and care.   Good winter project.

73 Mark K3MSB

On Sat, Jun 13, 2026 at 10:23 PM Michael Hanz <aaf-radio-1@aafradio.org> wrote:

Hi Mark,

The Signal Corps SCR-183 junction boxes do exist, but seem to be the most difficult to find.  There were only two designs made - Type TM-AE-172 covered SCR-AE-183 through SCR-AG-183, while Type TM-AH-172 covered SCR-AH-183 through SCR-AK-183.

Now, SCR-AL-183 did not have an official Signal Corps junction box.   
On its cording diagram was this rather tortured description:  
                        Fig. 20 
CORDING DIAGRAM FOR RADIO SETS 
SCR-AL-183 AND SCR-AL-283 EXCEPT 
A JUNCTION BOX TM-AH-172 (OR 
EQUAL) IS SHOWN IN PLACE OF THE 
NORMAL JUNCTION BOX WHICH IS 
PART OF THE AIRPLANE (NO JUNCTION 
BOX USING SOCKETS & PLUGS 
SUCH AS THE TM-AH-172, HAS BEEN 
DEVELOPED WHICH IS SUITABLE FOR
FOR USE WITH THE SCR-AL-283)   

With this set, the practice of forcing the aircraft manufacturer to provide the junction box began.  As far as I have read, no explanation was ever offered for leaving the TM-AH-172 out of the Signal Corps package other than the cording diagram rationale above.  The manufacturers, no dummies they, were happy to take over the $$$ job.  Initially the simplest solution is shown halfway down the page at https://aafradio.org/flightdeck/1935/SCR-AE-183.html  (It has the added advantage in our generation of eliminating half of the now scarce connectors you need to assemble the entire set.)  But the TM-AH-172 version (with the neat little window) continues to be shown in the later SCR-183/283 cording diagrams clear through the last "AS" model, labeled as part of the airplane rather than the Signal Corps radio set.  The one I have here was made by ARC and has a date of 8-14-37, so it had a long life without any internal changes.

73 Mike KC4TOS

On 6/13/2026 12:01 PM, Mark K3MSB via ARC5 wrote:
Yes.  I've managed to acquire all the components for an SCR-183 system.   It's been in the queue for a few years.... but...

At the recent Reading Airshow,  I was approached by someone that wants to have a display of a P-40B radio setup and asked if I'd help him.  He said the radios were the SCR-283 and provided me with links from which he obtained this info.      For next year, I think it would be nice to have my SCR-183 up and running next to the SCR-274N.

I do need a junction box, but from discussions from Mike Hanz, this will probably need to be hand-made.

I'm targeting Reading Airshow 2027 for the SCR-283 (Lord willing....)

73 Mark K3MSB

On Sat, Jun 13, 2026 at 11:34 AM arc5--- via ARC5 <arc5@mailman.qth.net> wrote:
Besides Mike Hanz and me, is there anyone left this side of
the pearly gates who cares for (meaning they do
something, not just add another box in the garage),
SCR-183 / -283?  How about GF/RU?

73 Dave AB5S

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