[MRCA] [Milsurplus] ATA ARA RX Alignment Question

[Mark K3MSB]

Hi Ken

Many thanks about not turning those rods!   I don't recall reading in the
manual they were push/pull, but maybe I missed it.

I decided to take the receiver to a friend's house that lives on the
tallest hill in the area (about 5 miles away)  as I live in a valley
surrounded by hills.

I easily picked up 6 or more stations (mid afternoon) with the DU-1 loop,
two of which almost blew my headphones off.   From my house, I'm lucky to
hear one.

Also, some of the noise I was hearing was not present, another indication
that my local environment is part of the issue.

As it stands now, I'm not going to do the alignment.   Ray does have a
point that these radios are 85 years old, although the IF cans in this
radio are adjusted via trimmer caps, not slugs.

All caps in the radio were replaced a few months ago.

73 Mark K3MSB









On Mon, Aug 18, 2025 at 4:04 PM kgordon2006 <kgordon2006 at frontier.com>
wrote:

> 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:
>
> https://m.youtube.com/watch?v=vlz83QXM66A&pp=ygUFVzdFS0I%3D
>
> Ken W7EKB
>
>
>
>
> Sent via the Samsung Galaxy S21 5G, an AT&T 5G smartphone
>
>
> -------- Original message --------
> Date: 8/18/25 07:13 (GMT-08:00)
> To: Mark K3MSB <mark.k3msb at gmail.com>
> Subject: [Milsurplus] ATA ARA
>
> *Subject:* [MRCA] ATA ARA RX Alignment Question
>
> I'm thinking of aligning my  500 to 1500 Kc receiver.
>
> Page 41 of the manual says to raise the protruding bakelite rods (of the 3
> IF transformers) until they snap into the up position.
>
> Delicately playing with one of them, it seems rather fragile, and I have
> to use a small pliers to move it -- I'm not sure what tool they used back
> then.
>
>
>
> It didn't want to move either way, and I was leery of giving it a good
> twist for obvious reasons.  The other two seem just as delicate.
>
>
>
> The radio plays but it a bit lethargic -- i was thinking of just doing an
> alignment with the rods as they were (although the manual frown on that)
>
>
>
> Comment from anyone that's done an alignment on this RX before?
>
>
>
> 73 Mark K3MSB
>
>
>
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