[TenTec] New and Coming 60 meter channels

Ken Brown ken.d.brown at verizon.net
Thu May 15 18:28:28 EDT 2003


George, W5YR wrote:

>Because it is not a damped wave which is what the old spark gap rigs put
>out. The dot or dash would start out at full amplitude and then start
>decaying or damping at a rate not to exceed a certain amount.
>
The damping occurs after each excitation of the tank circuit, which is 
many times within each dit or dah. In a rotary spark gap transmitter 
this would be determined by the number of contacts on the rotor and the 
rotational speed of the rotor. Other types of spark transmitters the 
excitation repetition rate would depend on various factors including 
component values and the type of rectification and filtering (if any) in 
the HV supply. In any case there were multiple tank circuit excitations 
and damped waves within each dit or dah. There was some kind of 
specification of the damping rate that relates to the bandwidth and the 
word "decrement" was used.

> The new tube
>rigs put out waves whose amplitude did not vary during a dot or dash, hence
>they were called "continuous waves."
>
>That is why it is called CW . . . actually a form of amplitude modulation.
>  
>





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