Wireless Set No. 52 Canadian - Project

[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

[Bob Carriere]

....had another closer look at the guts......and can't see where any modifications or parts replacement were done....... all the large paper condensers and not one "new" item added.......

Buyer beware!!!!!!

Bob C

[Bruce MacMillan]

having had a close look I can see many black Sprague TVA Atom series caps. These are fairly modern so I suspect some recapping has occurred.

[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.)

[Mike K]

This is a good article by Dave Lawrence. From what I have read about variometers, they are not ideal in a electrical sense , the rotary inductor or roller tuner is a better method of electrically adding length to the antenna.

https://www.qsl.net/ve3bdb/antmeas.html

These days, you can buy a nanoNVA device for hobby use. The VNA has the ability to analyze the complex impedance of the 19 set variometer and antenna and give a direct result in various forms. The nanoVNA are easy to buy on most of the popular retail platforms . And small spectrum analyzers are available for hobby use as well.

https://www.aliexpress.com/item/1005...d=gkAQdhUhNQmF

https://www.aliexpress.com/item/1005...170019037756_1