Wireless Set No. 52 Canadian - Project

[David Dunlop]

Since Starting this project, I have been curious about what company the Canadian Marconi Company subcontracted for production of the wireless tent kit they designed for the 52-Set.

The Parts list illustrations gave a very good description of the dimensions for the Wireless tent and its Valise. The tent itself was a slightly expanded version footprint of the then current 2-Man Officers Tent, with a correspondingly longer 2-Section Ridge Pole and pair of End poles. The valise was also slightly enlarged to accommodate thee larger tent components. The original Officers Tent Valise was never identified as such as it was unique to that tent. With the arrival of a slightly larger tent for the 52-Set to work from, the ‘TENT, WIRELESS VALISE’ identification was added to this valise, to avoid confusion in the field, in all likelihood.

To see if the manufacturer of the wireless tent could be identified, I posted the illustration of the valise on the MLU Forum recently and within 24 hours, Colin Alford had responded with some photos of a standard tent valise in his possession, with matching logo, name and date, S.S. Holden Ltd. of Ottawa. The original illustration, and Colin’s two photos are attached here, for your reference. It has only taken 80 years, but once again we now know one more subcontractor used by the Canadian Marconi Company during their production of the Wireless Set No. 52 Cdn.


David

[David Dunlop]

I was looking over my Carriers No. 4 a little while ago, primarily to refresh my memory about what work needs to be done to restore it. The actual restoration work breaks down into initial disassembly of all the little loose bits and separating the upper Box assembly from its lower Cradle assembly, when the time comes to work on it. Locate a few missing parts. Then straighten a handful of bent parts on the right hand side, strip off all the old NATO Green paint and then repaint it in as close as possible to the factory original No. 2 Brown paint. Let it all cure and then reassemble.

As far as missing parts went, the only ones I noticed I needed were all part of the Ground Terminals system located on the lower right side of the Carriers No. 4, where a pair of heavy duty wire braid grounding straps are used to maintain electrical continuity between the upper Box assembly and the lower Cradle assembly, across the insulation/isolation point of the rubber Bridges acting as shock absorbers for the 52-Set. The problem I have is the entire front Ground Terminal assembly is missing on my Carriers No. 4 and the rear assembly is badly bent and appears to be missing its wing nut.

The photographs in the 52-Set Manual suggested there definitely was a wing nut on the rear Ground Terminal, but the front assembly looked shorter in length overall and did not have a wing nut. Not helping was an illustration on Page 53 of the Operators Manual showing a wing nut arrangement on both Ground Terminals, but only the rear terminal actually in use. I got in touch with the owners of known surviving 52-Sets to ask how their sets were configured. All came back confirming just the rear assembly serves as the Ground Terminal, using a longer machine screw fitted with a wing nut and retainer D-Ring. The front assembly is merely a second connection between the upper Box and lower Cradle assemblies, using a shorter machine screw and hex nuts. No wing nut or D-Ring.

So with the help of other owners, I now know the rear Ground Terminal is a 1-1/4 inch long, 1/4 x 20 machine screw equipped with a wing nut and drilled near the end for fitting a D-ring retainer, to avoid loss of the wing nut. The front Ground Terminal is just a 3/4-inch long, 1/4 x 20 machine screw, both ground straps are 5.25 inches long by .75 inches wide heavy duty wire braid.

However, an unexpected discovery turned up in the process.

It seems the Engineers working on the design of the 52-Set at Canadian Marconi Company were quite concerned about the ground continuity for the set when in its Carriers No. 4. So much so, that where the holes are located fore and aft on the lower right side of the Cradle assembly, to which the bottom ends of the wire braid ground straps are secured, the Engineers designed in a large section of heavy duty copper plating against which the wire braid ends would be fitted.

Don Wright in Alberta brought these plated copper areas to my attention, because they have survived on his Carriers No. 4 finished in the factory No. 2 Brown, as per the attached photo. On the Cradle frame of my Carriers No. 4, the front Ground Terminal assembly was completely gone, but all I could see was a smooth NATO Green surface. Don assured me this plating should be there because it is quite thick and should even survive sandblasting, if done, when my Carriers No. 4 underwent its repaint to NATO Green.

Out came some fine emory paper and with just a few careful rubs, there it was, nicely outlined (second photo attached). Oddly enough, once I could see it, I could then feel it with my fingertip. At the front edge of the rectangle, where the NATO Green has worn and chipped over the years, I can now just make out the glow of copper down that line. I am going to pick away at this discovery with further careful sanding and a variety of cleaners to see just how much of this hidden bit of 52-Set design I can recover. Too hard to get at the rear Ground Terminal position at the moment, but it is now marked for a closer inspection when the time comes. The approximate size of this copper plated rectangle I have found is 3.0 inches long by 1.5 inches high.



David

[David Dunlop]

After some further careful fine sanding, scrubbing with a a small brass wire brush and several cleaners followed by a final wipe with acetone, my Carriers No. 4 has finally revealed its secret copper plating around the front Ground Terminal on the frame of the Cradle assembly.

The textured surface of the copper plate suggests this particular Carriers No. 4 underwent sand blasting prior to getting its postwar coat of NATO Green paint, so the odds of my recovering any of the factory original No. 2 Brown finish, have now been reduced significantly. But that is OK right now. I am just thrilled to have found this plating.

All of this prompted me to revisit the internet for more information on plating techniques and this particular process is apparently referred to as either ‘Selective Plating’, or ‘Brush Plating’. It is used for plating small, specific parts of larger objects that do not need full immersion tank plating, or for plating repairs. The same general principles apply as per tank plating. The recipient part is the ‘cathode’ connected to the negative side of a DC current. The ‘anode’ is still a piece of the particular metal that is to be the plating (copper, zinc, nickel, etc.) and it is connected to the positive side of the DC current, but the anode is actually inside an insulted tube, surrounded by an absorbent filling of fabric, filled with the appropriate electrolytic solution. The lower end of this tube is a wick allowing the solution to contact the cathode material being plated, thereby completing the electroplating circuit.

When I read all this, it jogged my memory of one of my uncles back in the 1950’s. He owned a 1956 Oldsmobile convertible, red and white. I cannot recall which model, but he got a scuff on the front bumper one summer and it was repaired by somebody who drove to his home and had all the kit in the back of a panel delivery truck. I watched him smooth down the scuff with some emory paper and then attach a ‘battery cable’ to one end of the bumper. He then pulled out a second cable with what looked like a small section of broom handle fitted to the end and start moving it back and forth over the scuff slowly for several minutes. And the scuff slowly disappeared. When this chap was finished, you could not tell the bumper had ever been scuffed and my uncle was very pleased.

So now I need to do some more internet reading to see if there are any DIY at home techniques documented for Selective, or Brush, Plating. This may be another handy skill to acquire.


David

[Bob Carriere]

https://www.ebay.com/itm/29566205094...sAAOSw9VpkSyzP

Looks like some one else has the WS 19 Bug........ love the homemade power supply. I have never seen one tested and on sale before.......

Bob C

[Bruce Parker (RIP)]

Originally Posted by Bob Carriere

https://www.ebay.com/itm/29566205094...sAAOSw9VpkSyzP

Looks like some one else has the WS 19 Bug........ love the homemade power supply. I have never seen one tested and on sale before.......

Bob C

Yet when I look at the pics I see all the old original paper components.

[Mike K]

Originally Posted by Bruce Parker

Yet when I look at the pics I see all the old original paper components.

I noticed the same issue. Those old capacitors will not be reliable, they need to be replaced. I also don't like the exposed high voltage terminals on the power supply , over 500 Volts

The Wattmeter is not to be believed - it will be adding up and displaying all of the harmonic and spurious content of the transmitter, giving a false reading. The load impedance needs to be matched to the output impedance of the set otherwise there will be a false indication of the actual power output.

[David Dunlop]

Hi Bob.

I did see this one. Pretty nice looking Northern Electric from the outside and showing all the usual Mods with an interesting bit of service History, if the case is original to the set.

According to the Sellers description, all original caps and resistors were replaced, but the old ones were all left in situ and merely disconnected. I could see that working in Receive Mode but I am not sure i would trust modern, caps and resistors designed for solid state voltages with 80 year old valve driven equipment putting it into Transmit Mode for any length of time..

Lots of photos posted but I cannot see any modern caps of equivalent design to the original paper ones anywhere. Either they are all extremely well hidden, or perhaps small, button style were used and hidden under the originals.

Any interesting curiosity, but I would pass on it.


David

[Chris Suslowicz]

Originally Posted by Mike Kelly

I noticed the same issue. Those old capacitors will not be reliable, they need to be replaced. I also don't like the exposed high voltage terminals on the power supply , over 500 Volts

The Wattmeter is not to be believed - it will be adding up and displaying all of the harmonic and spurious content of the transmitter, giving a false reading. The load impedance needs to be matched to the output impedance of the set otherwise there will be a false indication of the actual power output.

It's a very nice power supply, just missing the perspex/plexiglas sheet over the terminal strips and suitable DANGER - HIGH VOLTAGE labels.

As for the output power measurement, the EMERs specify a dummy load of (I think) 10 ohms and 30pF (plus a thermal ammeter) connected to the variometer output terminal in order to simulate an 8-foot whip aerial. Even that will include any harmonics, and you'd need modern test gear (spectrum analyser) to get any idea of the actual useful signal output - especially if using wire aerials or a different length of whip.

Chris. (I've got the "Dummy Aerial Set", but not the original Valve Voltmeter used with it (which is a little on the bulky side). Might try it with a later one at some point.)