That’s great performance for a receiver of that age and design! Nice clean job on the work under the chassis. I pulled a copy of AN-1630ARC5-2 and table 6-3 tells you that if your getting between 5 to 7 microvolts for 10 dB over noise
your making the curve. Your getting a good four or five dB above the average.
Ray F/KA3EKH
From: [email protected] <[email protected]>
On Behalf Of kgordon2006
Sent: Monday, August 18, 2025 4:05 PM
To: Ray Fantini via Milsurplus <[email protected]>; Mark K3MSB <[email protected]>; Military Radio Collectors Association ([email protected]) <[email protected]>
Subject: Re: [Milsurplus] ATA ARA RX Alignment Question
First of all, DO NOT twist those rods!!! They are meant to move only vertically.
Secondly, internally, they are literally soaked in beeswax and can be stuck. They SHOULD slide fairly easily up and down, but at this late date, they probably won't.
You may have to remove each IF can, remove the outer "case" and warm the beeswax until the rods move easily.
The selectivity improvemt with all three rods in the "UP" condition will be very noticable.
As far as sensitivity is concerned, the can caps are ALL defective by now. Trust me on this!!! You must either restuff them ALL with new caps, or simply replace them. I use 0.47 mfd metalized film 400 vdc caps.
The "ARC-5" receivers I have restored measure a sensitivity of less than 1 microvolt on AM, and even less with the BFO on.
I have never, yet, had to replace even one resistor in any of my receivers.
See this youtube video:
Ken W7EKB