MARCONI WIRELESS TELEGRAPHY c1919 LIFEBOAT SPARK TRANSMITTER Type 241C

[Richard O'Neill]

On 11/3/2014 3:22 PM, Nan and Sandy Sanders wrote:
> These were in use much longer than you might think. A ham I knew in 
> Baltimore said he signed an inspection on a spark transmitter in a 
> life boat on the mid 1950s.
>      Sandy
>     WB5MMB 

  That's about the time a friend and I were  building and operating 
spark transmitters in our neighborhood. The spark was struck between two 
carbon electrodes from D cell batteries held in wood cloths pins. Parts 
were mounted on a cardboard cigar box, our favorite chassis material 
back then. For power we connected to the mains with a 100 watt light 
bulb as a resistive load. It was crude and difficult to operate but 
worked well enough to be heard for several blocks when connected to a 
long wire antenna. Ah, the good old days. It's a wonder we didn't fry 
ourselves. O:-)

Anon