Hi MIke  (and everyone else that responded).

Mike,  thanks for the info.  I enjoyed reading your web page on this topic.

The mount is "legit"  -- It's an MT-269 AR:

image.png

As you might guess from the top of my unit, the original power circuitry is not going to be found.

image.png

Most of the HB Power Supplies in BC-221s are good candidates for window maker awards, but this one looks to be rather nicely built:

image.png

Looking at the photos / schematics on MIke's page,  it might be possible to duplicate the original circuitry, but at this time I plan to fix the installed HB supply (cap replacement, replace the selenium rectifier with diodes, etc).

Yes, the unit has the calibration book:

image.png

Good stuff!   Thanks for all the info.

73 Mark K3MSB



On Fri, Aug 7, 2026 at 6:48 AM Michael Hanz <aaf-radio-1@aafradio.org> wrote:
It's on my web page, Mark - a TS-164: https://aafradio.org/docs/TS-164.html

73,  Mike  KC4TOS

On 8/7/2026 12:05 AM, Mark K3MSB via ARC5 wrote:
> Hi Everyone
>
> I have a BC-221N that is not in the typical metal case for portable use.
>
> Rather, it's on a shock mount.
>
>
> image.png
> image.png
>
> I've not encountered one like this before.
>
> I know various bomber aircraft had a BC-221 (portable unit) stored on
> board,  and I'm interested in learning when this type of mounted unit
> was used instead.
>
> I didn't see anything in TM11-300.
>
> 73 Mark K3MSB
>
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