Wireless of the Week - week 22

[Bruce Parker (RIP)]

Of course Gunners speak loud...they have to over all that racket!! Once they leave the army, they speak loud because they are deaf I figure.

Any time I've seen ham operators use these speakers for their 19 sets it's by adapting a snatch plug attached to a control unit. I bet the army did much the same, whether sanctioned by an official set of instructions or not.

If this is so, it would use the two wires for the headset speaker and attach them to the lower '19 Set' terminal posts. If there was any though whatever of 'sending' on the 19 set from the speaker of course this wouldn't work without something in the middle like an RCU or field phone. While possible, I expect these things were more likely used for their intended purpose as a commander to battery communication.

One explanation for the upper and lower posts could be that the upper allowed communication to and from the battery commander located nearby. The lower 19 set ones could be attached to a second line system linked to a wireless set for listening to information from a remote FOO.

I wish I had the manual.

Originally Posted by David Dunlop

Bruce.

I was reviewing this thread again and a couple of things struck me in Post #1.

Firstly...don't Gunners speak rather loudly anyway?

Second. The photo of the loudspeaker with all it's original markings caught my attention, as one of mine is identical.

I have heard many people over the years say quite emphatically these loudspeakers were never used as an audio output for the No. 19 Wireless Set, they were strictly part of an artillery battery communications system. But the original markings on these loudspeakers clearly shows two distinct options for land line connection. The upper terminals would appear to be intended for the artillery tannoy system, and the lower terminals for connection to a 19-Set.

But how is the 19-Set connection accomplished? There are no direct land line terminals on the 19-Set. There must be some sort of interface component required to tie the two pieces together. I thought perhaps the near side Wireless Remote Control Unit might be the answer, but no mention is made at all in the manual for this remote control, for that type of usage.

I think there is a Control Unit in the Wireless Set No. 19 kit options that was designed with land line terminals, but cannot recall the reference number for it, or if the loudspeaker was its intended purpose. One would think instructions would have been printed somewhere covering this form of loudspeaker usage.

An interesting mystery. Thanks for posting.

David

[David Dunlop]

While I think of it, Bruce, do you have any idea what the correct khaki, web strap is supposed to be used with the Loudspeakers? I have seen plain straight straps, Satchel Signals straps with the shoulder reinforcement and the Fullerphone/Telephone style with the Ground Spike fittings. Haven't a clue which is correct.


David

[Jesse Browning]

The sexton has a 190 control box tapped for wires that run through the vehicle conduit to the speaker at the front of the crew compartment.

[Chris Suslowicz]

Originally Posted by Jesse Browning

The sexton has a 190 control box tapped for wires that run through the vehicle conduit to the speaker at the front of the crew compartment.

Looking at the Parts Identification List (FZ256/3), the 190 is very similar to Control Unit No.3 (A or B), except that there's an extra 270 ohm resistor somewhere on the top switch, and a 3-way tag board in place of the usual 4-way one in the top box. I suspect the resistor is connected in series with the feed to the loudspeaker terminals to limit the load on the WS19 output transformers and make it look a bit more like a set of headphones. There does not appear to be a volume control anywhere in the system, nor any facility for intercom use - the loudspeaker is output only by the look of it from the component listing.

Chris.

[Jesse Browning]

Chris; does your reference give the values of the different resistors? I made a No.190 box out of a No 3 box using the wiring diagram on the lid of the main electrical junction box in the radio compartment. It doesnt give the value of the resistors. What I would prefer is an original No.190 box.

[Chris Suslowicz]

Originally Posted by Jesse Browning

Chris; does your reference give the values of the different resistors? I made a No.190 box out of a No 3 box using the wiring diagram on the lid of the main electrical junction box in the radio compartment. It doesnt give the value of the resistors. What I would prefer is an original No.190 box.

Ah, there are actually two resistors on the top switch, and 4 on the Normal/Rebroadcast switch (those are identical on 3A, 3B and 190).

The two new ones on the 190 are

17 - 1/4 W. Metallized 5,600 ohms +/- 10%
19 - 1/2 W. metallized 270 ohms +/- 10%

(Numbers are on the parts layout drawing, not component numbers.)

I wonder if there's a circuit diagram for that box in the other EMERs.

More later...

...sorry, we don't appear to have a circuit diagram of the control unit with component values. It's not in the 'First Echelon Work" EMER, which is all about operator and electrician maintenance, and the "2nd - 4th Echelon Work" just covers the set internals in extreme detail - nothing about control units.

Chris.

[Jesse Browning]

[Jesse Browning]

Super! Thanks!