WS19 - Antenna Base fittings
 

Can anyone advise please... what is the correct antenna insulator to be using with my Sherman Firefly installation?

This is my collection to date... hoping at least one of them is correct.

Attachment 92445

My guess is the item middle bottom - this has captured nuts within the insulator so the bolts screw into it. I am assuming it is held in place by the nut on the end of the threaded aerial feeder which attaches to the back end of the Variometer... is this correct? The underside of this part is flat, save for a small pin which would stop it rotating.

Next question...

Of the two antenna feed plates... which of these is correct?


Does anyone happen to have the WS19 installation instructions for the Sherman VC please?

Cheers

Tim

Hi Tim,

On the assumption that it's a 'through the turret roof' mounting, the middle of the bottom row is correct. I don't think you need a feeder plate, as the aerial pigtail should reach from inside the aerial base to the end of the aerial feeder plate/tube from the variometer. (The "Plates, Connector" are normally only for cable or co-ax fed aerial bases, or setups with an external junction box/aerial support like the Daimler Scout Car where you have a short jumper lead from the variometer feeder to the bottom of the plate and the pigtail to the top of the plate.)

If the turret is drilled for the American aerial base you'll need various adapter washers and other bits because the hole will be far too large!

Chris.

I just had a look at the Challenger parts list to see what a similar setup would look like, but alas it doesn't seem to cover it (it stops with just the nuts and bolts that are needed to attach the mount).

The radio kit itself must be a different publication.

Just looked up in the EMER book. There isn't a firefly specific listing. However under the listing for the Grizzly the insulator is

Mountings, Aerial Bases, No1, mk1 ZA1825 PC 76456 C

Everything else seems to use the
Mountings, Aerial Bases No3, Mk1 ZA1827 PC 76555 C

Sigh....

It looks like the turret comes pre-drilled for the U.S. aerial insulator, so you need various extra bits to fit the WS19 aerial base and variometer:

ZA.1825 Mountings, Aerial Base, No.1 (middle of bottom row).
ZA.2948 W.S. No.19, Plates, Packing (not sure what this is at the moment)
ZA.2957 W.S. No.19, Aerial Feeder No.4 (short tubular one for variometer)
ZA/USA 1051 Variometer Adapter Plate
ZA/USA 1053 Variometer Adapter Washer

This is out of a late-WW2 US Mk.2 install for M4 tank, so is probably what you need.

I think the 'Plates, Packing' is a large square washer that goes between the aerial feeder and the roof, and the "variometer adapter plate" is actually a bar with a pin and socket to transfer the locating stud on the variometer to a drilled socket in the roof, clear of the large American hole. The adapter washer is dropped in from the top and serves to centre the aerial feeder in the large hole (after which the Mounting fits over the feeder followed by the tabbed washer and the securing nut). (Do NOT overtighten the securing nut!)

It is possible that I have some/all of these bits. Finding them may be another matter.

Right now I need sleep, I'm up at Oh God o'clock to go to Beltring.

Goodnight!

Chris.

No.1 has a steel plate with central hole and threaded bushes for the aerial base securing bolts. It's for a 'through the roof' feeder (Aerial Feeder No.4 or No.5) where the conduit of the feeder supports the variometer and is secured by a nut within the mounting.

No.3 is a plain disc which may be made of rubber, plywood, or steel (two cups seam-welded together) and has holes drilled straight through. It's a stand-off for use with the connector plate on a flat surface and requires nuts and bolts to fit it.

Later they were used together for the WS31AFV and WS88AFV to create enough room under the aerial base to terminate the aerial feeder correctly.
(This also required an additional fixture to simulate the 'conduit' of the WS19 variometer feeder.

Chris.

...and having got up at the appointed time only for the worthless bus company to fail to operate to the timetable (bus missing, next bus will get me to the railway station after my off-peak train ticket has expired, thus wasting 4 hours before it's valid again). I am excessively grumpy this morning.

That said, I have worked out what the 'packing washer' is for: it's square and supplied curved so that it allows the nut that secures aerial feeder to be tightened far enough that you can bend the tab on the locking washer without stripping the thread on the nut or pulling the tube out of the plate.

So, you want (from inside the tank):

Variometer.
Aerial Feeder No.4
Variometer Adapter Plate
Plates, Packing
Variometer Adapter Washer
----- turret roof -----
Mountings, Aerial Base, No.1
Tabbed lock washer from Aerial Feeder No.4
Securing nut (ditto)
Aerial pigtail (fit to aerial base first, then to end of aerial feeder)
Aerial Base No.8 or the rather better No.10
6 hex bolts and spring washers to secure aerial base (1/4-in BSF, I think).

It's possible that the adapter plate and packing plate go on in reverse order, but the adapter washer goes into the large hole in the roof in order to centre the aerial feeder in that hole.

You may have to drill blind holes to take the locating peg for the variometer adapter plate inside the turret and the aerial base mounting on the outside.
(The installation print may have diagrams for this.)

Chris.

This is what I have to date...

Attachment 92465

There is a pigtail on the underside of the No10 base

Does this look right?

Cheers

Tim

I guess am now answering my own question!

As have found this...

Attachment 92486

Parts I therefore need to find to complete what I need for the installation are:

Working from the Aerial Base down...

1 x Tab Washer - PC 47448C
1 x Variometer Adapter Washer - SD III R-140
1 x Variometer Adapter Plate - WA 623 - SD III R-113
1 x Plates, Packing No 1 - PC 76552C - ZA 2948

If anyone has any of the above parts they are happy to part with, please let me know.

Cheers

Tim

Another useful doc to add to this...

Unsure where this one came from - found it in an old folder while rummaging for something else!

First drawing - distance piece - is "Plates, Packing, No1"

Second drawing - Wooden Spacer - am not sure... might be the Variometer Adapter Plate... depends how big the US Antenna hole is on the Sherman.

Attachment 92494

At worst therefore I can make these parts now!

However, it would still be easier to find ready made bits - we have enough parts to make already.

Cheers

Tim

I have the last three items (NOS and still in their envelopes), and can possibly scavenge a tab washer (though that will mean I then have to find one to complete the feeder again).

Chris.
(Back from Beltring and just about recovering from it - I need some new knees!)

Chris

Have PM'd you on this.

Cheers

Tim

Tim,
In the first thread picture, it is the top left plate (in green with the black isolator). I am sure that the bottom left (metal colour) would work as well.
Doug

Doug

In that case, I am fairly sure I have one or the other of these spare.

I will have a look at the weekend.

Tim

Tim,
Thank you for the help in this matter. Will wait until you contact me again.
Take care,
Doug