Type 1216 Coil


Frequency Range: 300 and 600 metres
Power 250 watts
Circa: 1899 to 1913 (?)
Comment This Marconi coil was one of the most popular marine coils during its heyday.

Marconi began selling this type of spark coil when his company was first established  It was used as a complete transmitter before he began to add tuning in 1899 . After that, tuning was used when a ship was in port  in order to reduce the bandwidth of the emitted signal.  Without tuning, the voltage peak was much higher. He called this  PLAIN AERIAL. It would transmit 1/4 KW ,an had an average of 65 miles and 100 miles on rare occasions. Tuning was added with a coil in a wooden box on the wall and LEYDEN JARS as condensers. There were two tuned bands called BAND A (300 meters ), and BAND B (600 meters).

1216_1969_0878_001 .j
1216 spark gap transmitter. This artifact is held in the collection of Canada Science and Technology Museum, Ottawa. It is not known if this is a complete spark gap transmitter or just the coil and spark gap alone.  (Photo courtesy Canada Science and Technology Museum, Ottawa) 

These are all the components that are required for a spark gap transmitter .(Image courtesy American Radio Relay League) 
This is a typical early spark gap transmitter installation with Layden jars (for tuning ), and a tuning coil. It was fixed rather than variable.  ) and was located in in the large teak box. Photo courtesy Canada Science and Technology Museum, Ottawa) 
These Leyden jars have been disassembled to show their internal construction.  (Museum of Science and History Oxford)

0_in_coil_parts_fig247.jpg  Figure 247 - Parts of the 10 inch coil explained. Click on image to enlarge (From The Handbook of Technical Instruction for Wireless Telegraphists 1925 edition)

Contributors and Credits:

1) https://ingeniumcanada.org/ingenium/collection-research/collection-item.php?id=1969.0878.001

Back to Equipment Listing

Mar 15/21