Quote:
Originally Posted by Euan McDonald
Mike, the other one I have looks more like a ground mount.
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The one on the vehicle is Aerial Base No.10 Mk.2, which is quite late-on and continues in use until the Larkspur sets and the conversion to VHF.
The ground mount one is Aerial Base No.11, and fits on a metal spike.
The WS19 originally used Aerial Base No.8 for HF and Aerial Base No.9 for VHF.
Base No.8 had a "concave" profile to the ribber insulator and a truly appalling method of retaining the aerial rods: the brass socket was slotted like a collet and had a wire spring wound around it with the ends formed into looks so you could squeeze the loops to release the grip on the aerial rod. It was not a success, as flexing of the spring caused it to break after a while, and you got a _lot_ of flexing on a moving vehicle. It was replaced by Base No.10, though US manufactured sets were still being shipped with the No.8 when WW2 ended.
Base No.9 was for the 'B' set and took Aerial Rod 'G'. It required a dedicated mounting, and there were three basic types of a square base with upright pillar.
Base No9A was the Truck and Ground Station version, fitted to a spring clamp for easy attachment to a wooden post, vehicle hoop, etc.
Base No.9B does not exist - there's a variation of the 'B' set base with a flat bottom, rubber gasket, and clamp ring. This was post-WW2 Pye, used with civilian mobile radio and to use up surplus component stocks.
Base No.10 replaced base No.8 and has a convex rubber insulator and a mechanical clamp with a butterfly nut to securely hold the aerial rod.
Base No.10 Mk.2 was an improved version, the clamp was a single piece rather than two riveted together, and the convex rubber base went concave at the point it was bonded to the metal in order to improve the strength of the bond (The Mk.1 was prone to separate).
In addition, the clamp screw was threaded at both ends to allow an aerial feeder to be attached to the clamp - this allowed the set to be connected to the top of the insulator rather than being fed from underneath.
Base No.11 was the ground mount used with the WS22, R109, WS18 and WS19 in certain setups, etc.
Chris.