Antenna support, aluminum

[Chris Suslowicz]

Originally Posted by BCA

Any comments on the comparison of the Antenna Support, Aluminim, ZA CAN6000, PC 82495 C224 and the much heavier Base, Aerial Assy. Both have same hole sizes so can be used with the 20’ and 34’ telescoping antenna masts?

I can make a few comments, starting with "for some bizarre reason the part numbers on the ceramic base are lower than those on the phenolic one".

It's possible that it wasn't considered 'soldier proof', or that there were production difficulties, so they went with the repairable (you can unbolt and replace the moulded insulator if required).

It's also the direct ancestor of the insulator for the post-WW2 Mast, Telescopic, 27-FT (and mostly interchangeable with that - it will fit the later ground spike but not vice versa because the 27-ft mast insulator has a solid peg to fit a socket, not a tube).

The 27-ft mast (RACAL MA638, I think) is clearly a redesign of the Canadian 20/34-FT mast set. (Without the bulky pipe unions used in the original, and Terylene instead of cotton stays.)

I wonder if that was issued with the Canadian WS52, or if there was a different 'low loss' ceramic base insulator issued during WW2.

RACAL took over "Modern Antennas", hence the "MA" codes - the 27-FT Larkspur mast insulator is MA 638/31 or ZA.55466 (it will have an NSN as well, of course).

Best regards,

Chris.

[Chris Suslowicz]

Correction: the Canadian base can't be used with the 27-ft Larkspur 'Spike' - it's ribbed so won't enter the socket. My mistake, I didn't have them side by side at the time.

Masts will interchange, of course, and the Canadian masts will fit the British (flat plate) 'Roof and soft soil mount'.

The Canadian masts used a variety of insulators for the stays: plastic chain link, ceramic egg, and clear glass 'shell' types, I assume by different suppliers.

Chris.

[Colin Alford]

Brian,

I believe this type of aerial base has been discussed before but I can’t seem to find the discussion.

The 3 Mar 44, Working Instructions - Antennae Vertical 34’ Steel Mk I, mention that the Aerial Base was redesigned for the “Mk. 1 Kit“ (see attached text)

My impression is that the base in question may be the original design.

In post 14 of this thread: http://www.mapleleafup.net/forums/sh...ad.php?t=25447

Jordan B included the second attached picture which shows a Feb 43 instruction booklet.

Jordan,

Does your early booklet illustrate this type of aerial base?

Colin

[Chris Suslowicz]

I think there are three different insulators involved here.

1) The cast aluminium housing with brown glass/ceramic ribbed insulator.
This has stamped/cast-in numbers PC82495C-220 (bottom) 222 (top)

2) The cast-iron with phenolic insulator 'sandwich' issued with the WS19.
This has "Base, Aerial Assembly" PC82495C-285 and
PC82495C-286 (for the bottom) and -282 (for the top)

3) A later high-voltage ceramic insulator with number PC82495C-295 for use with the WS52 and WS43 (Canadian). (Which I do not have.)

My suspicion is that the cast-alloy one is the original design and was found to be unsuitable as being "too fragile", "too expensive", "not repairable in the field" and/or "impossible to produce in the quantities required". It's two aluminium castings, which would have to be machined, and a glass/ceramic insulator that was cemented in place. Aluminium was required for aircraft use and difficult to machine, and production would be complicated (and slow). If the insulator broke it would be difficult to replace (drill it out?).

Item 2 is much simpler: two fairly rough (externally) steel castings and a moulded phenolic insulator held together by bolts (plus a clamp lever to get a good contact between the top casting and the mast). Simple and cheap to produce in quantity and can be repaired in the field with spare parts and a spanner. Also considerably more robust than the first type.

Item 3 was to solve the power loss problem, and may not have been produced in large quantities because there were not that many WS52s built.

Has anyone seen Item 3?

Note: I have a "Campbell" instruction manual, but the parts list has been excised from the back and a different one (matching the WS19 common one) pasted in. I need to dig that out and look at the actual text to see if it describes the insulator in detail.

I've also got various "odd" parts of the aerial kit for WS19 - the original set of wire aerials on wooden board winders, and a 5-section clip-together set for use with insulator strings (3 x glass shells on a rope with a snap-hook at each end), plus a long halyard + pulley, again with snap hooks for the mast and wire aerial. The aerial had ben transferred to an American RL-29 winder from its original (I suspect) reel. I think I have an unissued sectional aerial still on the reel, but can't find it at present.

Chris.

[Colin Alford]

Gents,

I have found CMHQ files "55/5091/1 Antennae" and "55/5091/1/2 Antennae" They can be found at:
https://heritage.canadiana.ca/view/o...7/3734?r=0&s=3

The documents were placed in the file in reverse chronological order so if you intend on reading the entire file it will be best to start at image 3910 and work backwards to image 3734, skip to image 4085 and work backwards to 3911.

Specifications:

Specification O.S. 52 - Antenna, Vertical 34 Ft. Steel (Canadian Telescopic) Ref. No. PC 82495C-190 dated 5-11-42 can be found at images 3807 - 3824

Specification O.S. 145 - Antennae, Vertical 34 Ft. Steel Mk 1 Ref No. P.C. 82495C-300 dated 1 May 44 can be found at images 4004-4025

Updated Specification for electrical tests dated 14 Dec 44 can be found at images 3920-3921.

Nov 1942 User Instructions can be found at images 3826-3832

Design Change Instructions:

Can be found at images 3923, 3925-26 "Since the base is sealed during manufacture, it cannot be assembled in the field", 3954, 3957, 3961, 4026, 4028- 4031, 4050, 4052; and 4057-4059.


I will need to re-read the documents to properly digest the contents.

My initial impressions: The "First" specification from 1942 describes the Steel Aerial Base (I presume that this means the Campbell manual from Feb 43 will also describe the steel base). This would seem to indicate that the Aluminum base was not part of the "First" kit.

It seems that the Aluminum Base has a lower PC number, but a higher ZA/CAN number than the Steel base. Could these Aluminum bases have been produced and trialed during development of the 34' Steel Antenna, but initially deemed unsuitable, then at some later point they were taken into service and allotted a ZA/CAN number?

The two main specifications mention NDHQ file numbers "89-4-18" and "HQ 9070-12-17". There is some potential that these files are available online and might provide some pre-production development info.

Conclusion: More research is required!

Colin

[BCA]

Thank you Chris and Colin. I add that the early aluminum style (Chris's #1 model) has an assembly number (according to my Canadian microfiche) PC 82495 C224, 5955-21-106-4113. I agree with Chris that the upper portion is -220 and the lower portion is -222. This lightweight version is certainly easier to store and use.

[Chris Suslowicz]

Originally Posted by BCA

Thank you Chris and Colin. I add that the early aluminum style (Chris's #1 model) has an assembly number (according to my Canadian microfiche) PC 82495 C224, 5955-21-106-4113. I agree with Chris that the upper portion is -220 and the lower portion is -222. This lightweight version is certainly easier to store and use.

I think the PC stands for Procurement Catalogue, the 82495 is the 'group' number for the complete unit, the C to indicate "Canadian" and the -nnn is the individual component number (allocated sequentially by the designer).

On that basis:

PC84295C-224 is the Mast Insulator (lightweight)
- composed of -
PC84295C-220 upper casting
PC84295C-221 probably the glazed ceramic insulator
PC84295C-222 lower casting
PC84295C-223 probably the knurled screws for feeder connections

this is an earlier design/specification than the steel with phenolic insulator:

PC84295C-285 Base, Aerial Assembly
PC84295C-286 top casting
PC84295C-282 bottom casting
PC84295C-28? locking lever
PC84295C-28? pivot pin for locking lever
PC84295C-28? Phenolic impregnated paper insulator
PC84295C-2?? knurled screw - may be -220 as existing part

The final (ceramic) insulator specified for WS52 and WS43 (etc.) is:

PC84295C-295 (Which I suspect should really be designated the Mk.I*
because Mk.I is the first model issued (and becomes the Mk.I when a modification is made, which this certainly counts as).)

I need to find the various working instructions (etc.) for the mast kit, and see what level of detail is shown. A "Parts Identification List" would be good, of course, and may exist on that wonderful microfilm. (Which has interesting details about other things I wasn't aware of (such as the non-existence of Aerial Base No.19 - that was produced as a proposed replacement for Aerial Base No.10 Mk.2 that allowed the aerial to tilt, made it into various installation kit lists, but was abandoned in favour of Adapter, Aerial, No.1 ZA.27220 as an addition to the existing Base No.10 Mk.2.)

I have a library (of sorts) to search and sort/catalogue, but not tonight!

Best regards,
Chris.