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
I can undersand obscuring the nameplate to hide production info, but after the war?
KenW2EWL
On Sun, Aug 2, 2026 at 4:01 PM Hubert Miller via Milsurplus <[email protected]> wrote:
______________________________________________________________I have some RU GF equipment that has the SN defaced by using a small drill bit on the individual numbers. I had a statistics class decades ago and the instructor said the Allies in WW2 got some worthwhile idea of German AFV production by analyzing nameplates. I thought "Wow, interesting" at the time but now i think it was just BS to inject an interesting item to the class. I do not think there's any actionable info in some German nameplate or for that matter, RUGF equipment. If you have seen any 'clandestine' equipment you quickly see that the SNs have some unknown number offset and are totally bogus for any useful info.-Hue Miller
Sent from my Galaxy
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