Coil in a can

Coil in a can

Last weekend at the Electronics Flea Market I picked up some very strange items, including this one, pictured above.  It’s a tin can that looks very similar to an ordinary soup can, except that it has the following markings on it:



Thus far the only information I have learned from the markings are that NSC.OAKLAND stands for the former Oakland Naval Supply Center, closed a decade ago in 1998.  According to Wikipedia, NSC supplied components to the fleet in the Pacific during WWII.  Beyond this I have not been able to find any information.  Presumably this is a replacement part for some piece of obsolete military hardware.  A “coil” is another name for an inductor, a clue that this may be part of a radio system or other high frequency equipment.

After staring at this mysterious object for almost forever (a week) I decided to open it.  Realizing that the can could be full of cold war era hazardous chemicals, munitions, objects under high compression, or nasty sharp edges, I did this very carefully and documented the entire process of discovering the contents.

First, the obvious – opening the can.  Pretty straightforward.

Coil in a can

What’s inside?

Coil in a can

Weird.  Lots of oiled green paper.  Whatever is inside is packed very well, when the can is shaken nothing moves around.

This is the clump of stuff to come out.

Coil in a can

Packing material?  The precursor to styrofoam peanuts?

Below the packing material…

Coil in a can

What’s this?  Vintage dessicant!!!

The last object left in the can looks interesting.  It’s wrapped in oiled green paper and sealed with tape.

Coil in a can

Inside the paper we find this:

Coil in a can

Not a huge surprise – it’s a coil (inductor).  It has a knob or grabby thing on the top and a funny connector on the bottom.  It looks brand new.

Here are a few more pictures.

Coil in a canCoil in a can Coil in a can Coil in a can

The markings are “ARC” and “7270 239 KC”.  ARC might be American Radio Corporation?  239 might be 239 kHz (kilocycles)?  Hard to say, google didn’t turn up anythign interesting.

An impressive amount of stuff was packed into that can!

Coil in a can

This solves the mystery of what’s in the can, but what is it for?  Does anyone know?  I’d love to find out – leave a comment or contact me directly.

More photos are on flickr here.

9 thoughts on “Coil in a can”

  1. That is a common method of preservation. I’ve used parts that had been preserved in cans to repair the F/A18 fighters radar. When parts have to be stored for decades, the F/A18 parts were made in some cases in the late 70s, you need that level of protection.

    They use a heat sealed ESD bag for some of the newer stuff. The problem with those is that the plastic will vaporize both inside and outside the bag. The plastic will then coat the part making it expensive to remove either manually or chemically.

    One of the parts I used was a 4,000 dollar VLSI integrated circuit. It was about 4″x2″. It has two grams of gold wire and if done on a circuit board would have been three feet square using the highest density PC board technology available in the late 70’s early 80s.

  2. Mike – Your site is excellent! Thanks again for the info, and if you’re interested I still have a couple more unopened cans, let me know if you’d like one. It would make a nice paperweight at least. 🙂

  3. Happy to help, Jeff, but I’m not “one of the guys” at…I’m the *only* guy. 🙂 This is just a hobby for me. Sorry to give you the impression there are armies of folks behind the curtain…heh.

    – Mike

  4. Initial suspicions were correct, I just got an e-mail from one of the guys at

    Hi Jeff,

    These are the IF transformers that are components of the Navy ARA, USAAF BC-946, and AN R-24/ARC-5 broadcast band (520-1500kHz) receivers. They may be some spares that were produced in large quantities during the war. Nice find! These were less common than the other receivers of the period, primarily being for localizer systems that were not deployed in large quantities.

    Best wishes,

    So it looks like it’s not just an inductor but an IF transformer – I guess it still qualifies as a “coil”.

    The can has already become a pencil holder, not sure what I am going to do with the transformer yet. 🙂

  5. Windell –

    The knob does turn. It’s hard to tell if it’s actually doing anything or just spinning in place.

    A clever reader points out that this might be part of an ARC command set, like the ARC-5

    There is a photo of something very similar on a page about the original ARC type K here:

    and lots more photos of this monstrous transceiver station on this page.

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