[Milsurplus] R648/ARR41 serial number 573

Sat Aug 25 22:34:24 EDT 2018

ARR-15 is a cool radio but the bandwidth of the receiver is extremely wide on AM, like the ARC 38 but likely no issue during  military usage…   
Be nice to have a rack for the ARC-38 Meir, my homebrew cabling and pin connections to the power supply are a mess and moving it between floors caused some issue I’ve yet to debug.  Hope to get mine running again to join Pete and Jack on the OMRN…  Brown is also very close to having a non A version on the air..

Steve, kd3ht

From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Meir Ben-Dror WF2U
Sent: Saturday, August 25, 2018 1:58 PM
To: Mike Morrow
Cc: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] R648/ARR41 serial number 573

I have an R-648 which came to me with the panel handles broken, off (bad packaging)  but otherwise in OK condition. The previous owner hammified it by building an AC supply inside it on the dynamotor plate. I managed to find a dynamotor, without the plate, so I’m going to get rid of the AC supply components and mount the dynamotor on the plate. I have a suspicion (haven’t measured voltages yet, but the radio is working) that the filament chains were modified from the 24 V configuration to either 12 or even 6 volts. I’ll need to restore the filament wiring. Luckily, the radio came with the power connector intact (one of the favorite hacking jobs is to remove them), just a few wires unsoldered from it, but the original wires are there tied off. The AC cable is connected via the correct plug, I guess the wires are disconnected to accommodate the AC operation without discarding the 24 V runs, which is good as far as restoration goes. I wish I could find a pair of handles – I know Fair Radio used to have R-648 carcasses but they told me that even these were stripped and they don’t have handles. I managed to find a mount, so the end product when I’m done with the restoration, will look good – disregarding the lack of handles…
I now also have a decent looking original ARC-38 (non-A!), with the control box, power supply on the mount, and mount for the ARC-38. The mount in fact is not original, it’s for some other – unknown piece of avionics, but the width and the locking mechanism fit the ARC-38. A local ham friend, who has a nicely equipped machine shop in the hangar attached to his house (he built his aircraft) simply extended the mount to the ARC-38 length using aircraft grade stock, and riveted the thing together with the flat aircraft rivets, so the mount looks completely factory built. I also have the connector that plugs in to the back of the ARC-38.
To top all this and have a nice ARC-38/ARR-41 setup, I found a P-3A radio compartment electrical distribution/circuit breaker panel, with the ARC-38 and ARR-41 nicely marked by their circuit breakers. That’s where I’m going to feed the 28 VDC to the radios!

Anyway, it’d be nice to find the handles for the receiver, because I don’t know whether I’d be able to fabricate them to look original.

73, Meir WF2U
Landrum, SC

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From: Mike Morrow <mailto:kk5f at earthlink.net> 
Sent: Saturday, August 25, 2018 10:18 AM
Cc: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] R648/ARR41 serial number 573

There likely were AN/ARC-38A and AN/ARC-94 Collins HF sets on that P-3A.  The AN/ARR-41 was the aux receiver for the AN/ARC-38 and -38A.

I've got a couple of AN/ARR-41 sets in working condition, and one that's not.  Twenty years ago they were pretty common, but not the mounts.

Mike / KK5F

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