Ham4CW
Administrator
This fine old key is around 103 yrs old. As far as I am aware these were used to either key two seperate lines at the same time, or, they could be used to reverse the charge on long submarine cables and landline circuits.
The idea was that a long coaxial cable acted like one huge capacitor, and as such would store the the signal 'charge'. Although grounding out or shorting the cable would discharge it, it was found to be quicker to apply a reverse charge. These keys, with their double set of contacts could do that.
No doubt they had a 101 other uses too. These keys have a very odd 'feel' to them. Unlike a lot of keys where the contact itself forms the stop, on these the contact arms are a soft springy metal, and the physical stop to the arm is made by the extended vertical 'rod' directly below the operator button (knob). This bar, when the key is pressed down, strikes a brass plate in the base of the key to bring it to a halt.
However, before the arm gets near to this stopping point the contacts have already closed and the arm movement is already being resisted as the flexible contacts begin to bend under the force. Overall this gives the key a very mushy feel to it, quite odd when in use.
As can be seen from the images below, there is a lot 'going on' under the base of this key as well as above.
The key has never been cleaned, but the contacts are still electrically fine.
There is more info on these type of keys to be found on G0RDO's website here >>> http://www.morsemad.com/dc.htm
73, Mark...
The idea was that a long coaxial cable acted like one huge capacitor, and as such would store the the signal 'charge'. Although grounding out or shorting the cable would discharge it, it was found to be quicker to apply a reverse charge. These keys, with their double set of contacts could do that.
No doubt they had a 101 other uses too. These keys have a very odd 'feel' to them. Unlike a lot of keys where the contact itself forms the stop, on these the contact arms are a soft springy metal, and the physical stop to the arm is made by the extended vertical 'rod' directly below the operator button (knob). This bar, when the key is pressed down, strikes a brass plate in the base of the key to bring it to a halt.
However, before the arm gets near to this stopping point the contacts have already closed and the arm movement is already being resisted as the flexible contacts begin to bend under the force. Overall this gives the key a very mushy feel to it, quite odd when in use.
As can be seen from the images below, there is a lot 'going on' under the base of this key as well as above.
The key has never been cleaned, but the contacts are still electrically fine.
There is more info on these type of keys to be found on G0RDO's website here >>> http://www.morsemad.com/dc.htm
73, Mark...
