MWT. Marconi's Wireless Telegraph Co. Ltd. London, Key 1905 (?).



This rare key is a Marconi's Wireless Telegraph Co. London wireless key from around 1905 (?). beautifully made simple key with hard wood base and brass parts. Serial number "2" written on base and bottom. The base is quite deep ( 1 & 1/4" or 32mm) and houses a large condenser / capacitor of .25uF that was fitted to help reduce sparking at the keys main contacts. The key's contacts are smaller than a regular spark key at 3/16" Dia. The Antique Wireless Association or "AWA" Volume 14 of 2001 has some interesting information on early Marconi keys, and dates this type of key from an early British Marconi catalog to 1905, and the 6th design Marconi key. However I am not sure of the date and these style of keys could be from 1905 - 1920.


The key design is typical of early Marconi keys, with the main arm cut-out on top. The arm is also cast hollow to reduce weight. Dimensions of the base are 6" by 3 & 1/2" by 1 & 1/4" deep ( 155mm x 90mm x 32mm). Some keys have labels and some not. The condenser/capacitor can be seen on the right picture. It is black rectangular and has .25uF plus a circular emblem "BI" (British Insulated Cables Ltd. Prescot, Lancs. England. c 1890).


Three Terminal MWT Co. Ltd. London Key.



Marconi's Wireless Telegraph Co. London wireless key with 3 terminals. The letter "R" is written on base and bottom. Note the addition of a third terminal providing press to break back terminals.


MWT. Marconi's Wireless Telegraph Co. Ltd. London. Key & Buzzer c 1900's.



This rare key is "A signal generator / with key / for checking out Marconi tuners" (thanks to David Ring N1EA). dated from about 1907. An interesting key on a mahogany base. Inside the base is a buzzer, an inductive coupling that connects to the 4 terminals, and a space to take a battery. The base measures 7 & 1/2" by 3 & 1/8" and is 1 & 1/2" deep. The brass plaque reads "MARCONI'S WIRELESS TELEGRAPH Co Ltd No 28755 LONDON".

Further quote: "Without a large antenna, a tuner would be silent as dust on an attic floor. Using a buzzer generates a spark signal which was used to check and align old detector sets. RCA had a crystal receiver tuned for 600 meters (500 kc/s) which I used on several ships. You needed some spark signal to act like smelling salts for the old deaf receivers". David Ring N1EA.


The key design is similar to the American Bunnell Triumph keys that had an oval shaped frame. This however, has a round frame at 2 & 5/8" Dia. The wooden base is stamped with the number 22.

MWT information by George Saunders / G3OYN : "MWT 'Instrument Numbers' are not serial numbers. They began around 1907 as a straight numerical series, applied to anything built, without distinction, which could perform a function. So 123456 might be the instrument number for a transformer, 123457 may be the number for a portable test meter, 123458 might be the inst. no. for a complete HF communications receiver, and so on.
This had great benefits to the company. It was impossible for rivals to discover how many of one type of equipment had been built, and hence the manufacturing capacity of the firm. Because much of the production was for various home and overseas governments, and their fighting services, this method helped their secrecy by denying valuable information to any "opposition'' A straight serial number would not have given this advantage.
See prof. R. V. Jones's book ''Most secret War" for the good use made or enemy serial numbers in the Bruneval radar raid. Also, of course, the MWT company was always willing to build a "one off" for a valued customer The firm did not deal with the general public - it only made high-value capital goods for professional users".

"MIMCO (1930 0n) followed normal commercial serial-number policy. They had no confidential installations, and leased (rather than sold their equipment to ships. Most (but not all) or their equipment was built by MWT for internal sale Development (unsaleable) prototypes were numbered 099 and down; production equipments numbered from 101 upwards. Various government type- approval testing could only be done on production equipments, so the first ten or so of a new equipment were expended on this. Equipment recovered when a ship has broken up was returned to Chelmsford - even from places like Hong Kong. If still current, and in good condition, it could be "wiped up" and tested fit for reissue. If repair was needed, or the condition was not good, they could be sent to MWT for refurbishing. This meant stripping down to chassis (and replating if needed), making new cable-forms and tagboards with minor components, and so on. This was cheaper than ordering new equipment. It also meant that if MWT orders were slack, then there was a supply of work to keep the works ticking over". George Saunders.


Marconi's Wireless Telegraph Co Ltd London "D TYPE" Key.

I have only ever seen one of these Air Ministry keys with MWT labelling. If you know of another, please let me know. This one is stamped "MARCONI'S WIRELESS TELEGRAPH Co Ltd. No 58762 LONDON."


A Beautiful Brass Key On A Marble Base. British Marconi - c 1930's. Rare.



This is a beautiful key indeed. Dated from around the late 1920's to the early 1930's. A brass key on a brown marble base. The threads are 2BA (and small ones 6BA). Measurements are: Marble base measures 6 & 3/8" by 3 & 1/4" with a cork under base. The cork base looks to be glued with shelac. 1/2" dia bearings. 1/8" dia silver contacts. 1 & 1/4" dia knob with a 1 & 3/4" dia skirt, both in grey bakelite. Grey bakelite was popular in the 1930's.



The patina shows a key of considerable age, and the workmanship is superb.


Interesting in that both the lower and upper contacts are fixed with hex nuts. It is usually found that just the lower contact is mounted like this - as in the Marconi Navy key, the AP 7681.


"BK"