Mystery antenna mount

[derk derin]

Can anybody identify what type of antenna mount this is? From the design of the spring & socket where the antenna Rod fit in I’m assuming it’s a WWII design?
Cheers,Derk

[Chris Suslowicz]

I'd agree that it's early WW2 (the later aerial bases had a screw-up clamp rather than a spring around the outside of the socket), and I don't think it's British.

If it's all-metal, then the only way it can work is if it sits on an insulator with a curved top (Ebonite?) and is fed from below through the vehicle roof. Aerial feeder would then be a cable to the threaded tensioner, but it must have been complicated to set up and keep working.

(The huge "Aerial Lead-in No.16" has a similar feed arrangement with a threaded stud, but is considerably more robust (and has a rubber base above the feed-through section to allow the aerial to flex/sway when the vehicle is moving.)

Are there any numbers stamped on it?

Chris.

[derk derin]

No markings whatsoever but the green wrinkle finish on the mount seems like the green wrinkle finish on the American wireless 19 set case. It could possibly be an American antenna mount? The spring inside the body that the cable runs through and attaches to the threaded stud makes it somewhat flexible if it needs to bend.
It is constructed of all metal.
Derk

[Chris Suslowicz]

Originally Posted by derk derin

No markings whatsoever but the green wrinkle finish on the mount seems like the green wrinkle finish on the American wireless 19 set case. It could possibly be an American antenna mount?

The paint finish marks it as "Made in USA", I think (coupled with the lack of identification markings), but the "wraparound spring" aerial rod retention method was British/Commonwealth (Aerial Base No.8 and the "Laporte" adapters), later replaced by a screw clamp for Base No.10 and later types.

The spring inside the body that the cable runs through and attaches to the threaded stud makes it somewhat flexible if it needs to bend. It is constructed of all metal.
Derk

It's got to be insulated from the vehicle body, and there's a big air-gap where any such insulator (ceramic or rubber) would go - with a curved top surface to allow deflection if it hits something, and the spring would re-centre it afterwards. It's fed from below, so AFV or wireless truck use.

Fitting it would be a matter of taking the nuts off, feeding the threaded rod and cable through the insulator into the vehicle, then fitting a washer and lock nuts to tension the spring (not too much or it'll break contact at the top), then fitting the aerial feeder and another couple of nuts.

That's my guess, anyway.

Chris.

[Chris Suslowicz]

I wonder: does it fit "Insulator, W/T, 'H'"? (The large "mushroom" that was the base for "Aerial Lead-in No.16" and other Wireless Body or high power applications.)

Chris.

[Chris Suslowicz]

IDEA!

Is it an early version of the "Aerial Base C2" used on wireless trucks?

The one shown as "Fig.9" & "Fig.10" on pages 41 & 42 in the Wireless Sets, Canadian No.52 Vehicle and Ground Stations book (ZA/CAN 0077) from May 1944 looks as though it could be a development of this. (It's certainly got the threaded rod that goes through two ceramic insulators - on on each side of the roof plate - with one nut and a wingnut (with an optional extension rod for certain installations similar to the British "Aerial Lead-in No.16").)

May have been for Wireless Set No.9, the precursor of the WS 52?

(I suspect it was too rigid for use on the move with 'F' rods inserted, and the main purpose was static use with 'F' rods or to provide a feed to the telescopic mast (20-ft or 34-ft) and/or wire aerials in a static role.)

Best regards,
Chris.

[Bruce MacMillan]

not the greatest diagram but this mount is for the WS9 Mk1. Looks like a roof mount.

[David Dunlop]

That is a great match to the mystery mount, Bruce.


David

[Chris Suslowicz]

This monstrosity is the British version... clearly the Canadian Marconi Company had more sense and simplified it! (From Signal Training, Volume III, Pamphlet 25.)

It takes Aerial Rod 'D', I think, so the Canadian version is simplified (!) for ease of production and to take Aerial Rods 'F' instead. the "pinch the spring" clamp is the same as on Aerial Base No.8, and the missing parts are the steel (or Paxolin) plate with the large central hole, and the insulators that fit on either side of it. The curved "skirt" is probably a rain shield to keep water off the ceramic insulator.

Chris.

[derk derin]

My god that looks like a complicated antenna mount!
Derk

[Chris Suslowicz]

Originally Posted by derk derin

My god that looks like a complicated antenna mount!
Derk

It's from the early days of mobile wireless, while they were still working out how to do it. I think this is a modification thrown together to fit a vertical rod aerial instead of the "Roof Aerial" while not modifying the vehicle too much.

Sanity returned after the "Roof Aerial" was abandoned as hopelessly inefficient and far too bloody complicated. It's probably mid-1930's tech, if not earlier.

The replacement was "Aerial Base No.3" which was still top-feed so needed an "Aerial Lead-in No.(whatever)" and then that was modified into "Aerial Lead-in No.16" before being simplified into "Aerial Base No.(20 or 25, I can't remember)".

(I'm collecting the aerial bases as they turn up, but it's slow going. Some of them were _very_ short-run, or in the case of No.19 a single prototype.)

Chris.