Wireless of the Week - week 5

[Chris Suslowicz]

Riiiiiiiight.... all becomes clear.

It fits on Aerial Base No.16, which consists of a (modified?) Aerial Base No.3 on top of Insulator W/T "H" (which is a substantial ceramic piece). This was intended for (relatively) high power sets (WS19HP, WS12, WS53, etc) and the Aerial Base No.3 was not up to the job of insulating that much voltage. So: the ceramic (W/T 'H') provides the insulation and feed-through into the vehicle, and the No.3 is bypassed by four braid straps and just acts as a vibration mounting.

This is fine for a few 'F' rods, but once you start stacking 'D' rods, the hollow rubber Base No.3 will collapse, so you need that bracket to support the weight of the vertical aerial. Obviously you can't use it on the move, and since it's only supporting the weight of the rods, it doesn't need to be fastened on (certainly not bolted down, anyway).

I'm currently cleaning up a Base No.16, and noticed it has four large flat-headed studs on the clamp ring, so that's obviously what the slotted lugs on the bracket mate with. (Drop it on top, rotate into place, feed your first 'D' rod in and tighten the clamps on base and bracket, then add more rods as required. (Or fit the bracket to the assembled vertical before lifting it into position, then slide down, rotate, and clamp in place.))

Once I've got it cleaned up I will see about some photographs of it.

Chris.
(And that bracket is something else to look for on this side of the pond.)

[Chris Suslowicz]

Aha! I seem to have two variants of Aerial Lead-in No.16, plus the mounting hardware for both types.

The first type is for "15cwt 4 wheeled Wireless Truck Mk.III" and fits on a bracket over the cab. Feed is via a "blackout box" on the end wall and an "Insulator W/T lead in No.12" (two glass dome insulators in a square panel).
The four braid straps that bypass the rubber insulator on Base No.3 are fitted to the top clamping ring. See WftW Vol.2 Page WS19-74 which is for a (British) WS19HP install.

The second type is for "House Type Body" wireless trucks (15 cwt Mk.II), LCV and ACVs, and the post-WW2 Austin K9. This fits to a paxolin plate in the centre of the roof and is fed directly through the base. (It allows the safe use of rather higher powered transmitters like the WS53 and RCA 4332 and BC-610, where the feeder can go straight up from the set to the base and be protected by an earthed metal guard.) For this version, the braid straps are fitted to the plate that the Base No.3 is clamped to, and the clamping ring has gained the studs that the "Bracket, Aerial Clamping" fits onto. (It has to rotate anticlockwise (viewed from above) because the studs for the (now unused) braid connections are next to the new ones for the aerial bracket.)

Photographs of all this stuff once I get the camera sorted out and the "first type" of base unearthed and cleaned up!

Chris.