Radio Telegraph

After I did the Railroad Telegraphy post I thought I would mention another type of key and keyers. The electronic fully automatic keyer that uses "paddles". Instead of just two wires with bugs and straight keys, paddles have three wires, one for dit, another for dah and ground. They go the keyer. Close the contact between the dit wire and ground and they keyer generates dits for as long as the connection is made. Dahs are generated the same way, continuity between the dah wire and ground. To my knowledge, these keyers were never used with the railroad.

What happens if you close both contacts at the same time? Glad you asked. From Wikipedia:
"Iambic keying or squeeze keying creates alternating dits and dahs. This makes sending some characters easier, like the letter C, by merely squeezing the two paddles together. In single-paddle, non-iambic keying, the hand motion would require alternating four times for C (dah-dit-dah-dit).
Iambic keyers function in one of at least two major modes: Mode A and Mode B."

See the wiki article for the differences in modes. 

My newer ham radios have keyers built in.

Photos of my iambic paddles:

MFJ-564 similar to Bencher BY-1/2

Brown Bros Model BTL-A

dit dit