My submission here won’t add much to the topic, but….
The elementary stats course, the instructor recounting the anecdote said that the Allies learned useful facts from the serial numbers on tanks.
I don’t know; i reserve opinion, but i tend to think, how much of an advantage was this ?
I have an RMCA AR-8501 mid-1930s ship receiver. The seller told me that RMCA in those years, leased the receiver and then user was locked into
a legal agreement. I don’t know. I would expect this situation would have been ended by the exigencies of the world war. This exclusivity, it seems
to me, just would not work with the numbers and dispersion of cargo ships.
-Hue Miller
On Behalf Of
Brenda Gentry via Milsurplus
Sent: Monday, August 3, 2026 10:44 AM
To: milsurplus
Subject:
Re: [Milsurplus] RMCA LF Regen AR-8503
When one is dealing with commercial marine radios used by companies that also were marine communications companies, legal things can be weird
and very nasty. In those times, the ship owner leased the equipment and often the operator(s) from a communications company. They had unbelievable restrictions on which replacement parts, like tubes, could be used in the equipment. I believe all of this has
been eliminated since then, but in the mid 20th century they were still in force. If you look at an old vacuum tube, such as a 1940s RCA, the tube is often labeled "Licensed only to the extent listed on carton". Plugging that tube into a commercial marine
radio could trigger nasty legal actions from the communications company. You were required to buy and use the exact same 6SK7 from RCA Radiomarine at 5 times the price. Similar edicts applied to some sound systems in theaters and network radio stations. Most
of these were declared illegal in the late 1930s, but some remained into the early 1950s. When RMCA sold equipment to the military, they wanted to keep anyone from using it on a commercial ship after the war so they forced the military to mutilate the serial
number.
Brenda Gentry, KA2IVY
On 8/3/26 12:51 PM, Ken Kinderman via Milsurplus wrote: