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  #1  
Old 04-02-17, 14:04
Mrs Vampire Mrs Vampire is offline
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Default No 19 Help

Hi

I am putting the 19 gear into my Stuart. M3A1

The set up is a JB No 2 on the fwd face of the stbd sponson in front of the 19 set for Bow gunner.

A JB No 1 above the driver ( I take it the No 1 has only a single headset lead. )

And a JB No 3 in the Turret for gunner and loader .

Does any one have clues where I might get a couple of No 1 JBs ( two tanks to fit.

I have the photographed JB which I cant identify . It has seven outlets and a single button .

I am also puzzled by the antenna set up . I have two antenna base brackets. One on the stbd fwd rear deck just behind the battery box and another on the top of the curved rear armour on the tank centre-line.

Photographs and logic tell me the on on the rear curved armour is the long HF antenna as it is outside the circle of the main gun and the one on the stbd side is the VHF set s the antenna is short enough to pass under the main gun

well that"s my theory anyway. I have few good photos to go on

Now the book suggests the vhf antenna has an aerial base No 9 a mounting base 1 and a rod G . The HF Aerial base 8 and rod F .
I have plenty of the 8 bases and rod Fs....

Curiously the brackets on the Tank , and they are certainly original are both drilled for Aerial base 8

My question ...was the no 8 base used for both VHF and HF sets??

I have also come across a few examples of turrets ( flat top so Hybrid or M3A1 ) with a mounting bracket for a No 8 base welded near the commanders pistol port.

I don't understand how an aerial on the side of the turret would work given there is no room for a wireless set in the turret .. ( commander and loader would have to be on very good terms) and running a lead up from a set in the fighting compartment would restrict traverse and be a real mess with all the other gear in the turret.

maybe just for a walki talkie??
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  #2  
Old 04-02-17, 14:34
benamucke benamucke is offline
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Default Junction Box

I think that box is the "Call Commander" one.
Ben in Toronto

Last edited by benamucke; 05-02-17 at 12:17. Reason: Clear up
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  #3  
Old 04-02-17, 18:31
David Dunlop David Dunlop is online now
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Gina.

I am a little fuzzy about the variations in the Stuart family. Does your model have the short sponsons, originally intended for machine guns, or the later stretched sponsons?

I believe the British discovered the machine gun idea was ineffective fairly quickly and did away with them, utilizing the space for extra storage, one item in particular being the location of the 19-Set in the right side sponson. Early Stuarts also had no turret bustle at the back, so no space at all there for the wireless to go.

You have correctly identified a critical problem when installing a wireless set in an armoured vehicle with a turret. The set and the aerials must all be located in the same place: hull or turret. No cross overs allowed.

The A-Set (HF) is the longer of the two for the 19-Set so if the set goes in the right sponson on the hull, the A-Set aerial must be located somewhere on the hull to clear the traverse of the main gun. The curved plate location you described makes sense. Also, the A-Set aerial system is very tolerant of differing transmission cable lengths from set to aerial. The variometer solves that problem.

With the B-Set (VHF), however, distance from set to aerial is critical to the extreme. The B-Set transmission cables are tuned lengths and must not ever be cut. If memory serves, they come in three lengths only, the longer two being multiples in length of the shortest one and all are directly related to the wavelength the B-Set operates on. Long story short, the B-Set aerial must be installed on the hull, somewhere in close proximity to where the 19-Set is installed.

I have a photo somewhere of either a British or Canadian Stuart with the short sponsons and the B-Set aerial system is installed on the outer edge of the right front fender, directly in front of the sponson. Interestingly, the mounting for the No. 9 Base is not the typical heavy steel pipe with the square four hole base plate. It is the two to three foot tall small steel tube type mount. This mount sports a large round rubber cylinder shaped base with a circular steel plate at the bottom, which I believe is drilled with the same hole pattern as the Mounting No. 8 for the HF aerial. The top of the steel tube has the fitting for the B-Set aerial, Mounting No. 9. The angle of the photo is a bit low, but it looks as if the height of the aerial mount needed brings the base of the aerial to a point close the the top plate of the turret. The B-Set aerial must be fitted high enough to clear the main steel mass of the vehicle, otherwise the signal gets blocked.

Hope this helps a bit, Gina.

David

Last edited by David Dunlop; 04-02-17 at 18:36.
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  #4  
Old 04-02-17, 21:29
Mrs Vampire Mrs Vampire is offline
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Thanks David.

I guess I had better figure oput the cable lengths for the VHF .

All the Stuarts up to the M3A3 had the same length sponson. So mine a mid production M3A1 has the same length as the first M3.

The sponson guns were removed early in the piece and never used in Australia. They were removed as much for their ineffectiveness as for the desperate need for room in a cramped M3 series interior.

The Australian Stuarts had the 19 set in the stbd sponson from the first and never used the radio shelf that was at the stbd rear of the fighting compartment in the M3.
Our first 40 M3 came from the Uk and were modifies in accordance with the then UK standard....many of those mods were done away with before they were deployed to training and the 1st armoured. The smoke discharges and radio set location being two.

The British location for the 19 set on the shelf at the rear of the fighting compartment was a very bad idea. It was behind a 37mm storage bin and ideally located to either trip up the loader or provide a handy step for him . It was complete hazard when the turret was traversed...

Any photos of antenna set ups would be greatly appreciated .
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  #5  
Old 04-02-17, 22:43
David Dunlop David Dunlop is online now
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Well, I was almost right, Gina.

Seems they may only ever have been two cable lengths ever available for the 19-Set B Aerial, both based on multiples of the wavelength of the VHF frequency that was used. My confusion stems from the fact that at some point during the production of the set, the nomenclature for these cables was changed. Hopefully the following will be of help:

Aerial Feeder No. 2 (became Connectors, Coaxial, No. 11) was 4 feet 2 inches long - 1-1/2 wavelengths

Aerial Feeder No. 3 (became Connectors, Coaxial, No. 11A) was 7 feet long - 2-1/2 wavelengths

If the Mounting No. 9 for the B-Set needs to be close to the top of the turret for optimal signal strength, factor the distance from hull deck to top plate of turret from the longer cable length. Whatever length is left over, will give you an idea of how far away the 19-Set can be from the B-Set aerial assembly. I guess in your case, you already know the 19-Set location so the B-Set aerial location limit would be dictated from that point. My guess would be somewhere on the right hand side of the hull. One would waste too much cable trying to run it anywhere across the vehicle.

David
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  #6  
Old 05-02-17, 05:39
Mrs Vampire Mrs Vampire is offline
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Thanks so much for the info David

all very helpful as i wish to have the radio operational especially the intercom.

Any clues where I can get junction boxes ??
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  #7  
Old 05-02-17, 06:46
David Dunlop David Dunlop is online now
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Never actually searched on line for Junction Boxes to be honest, Gina. Used to be a surplus dealer locally with lots of them, repacked and in sealed clear plastic pouches, but I think he flogged them out somewhere.

Personally, I would first try searching the web for them via any name/descriptions I could think of to see what might turn up, where and what descriptions, if any, provide search results.

I would also follow up on any 19-sets, or major components thereof that pop up on line for sale. In the past couple of years, I have seen a couple of sets turn up in the USA that were clearly being parted out from Sherman installation kits. Lots of bits showing up from the same seller. In these cases, it never hurts to contact the seller and ask if they have what you are looking for. Often a seller not familiar with particular equipment only flogs what they have referenced can pay good money. If they cannot evaluate other pieces, they ignore them. Over the years, I have picked up a number of wireless bits this way, for very reasonable prices.

There are a couple of retailers in Europe come to mind as well. I will look them up and PM the info to you tomorrow. No guarantees, but it will not hurt, to contact them and ask.

Cheers for now. I have a dog and cat staring at me at the moment wondering why the hell we have not gone to sleep yet.

David
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