Don Wilhelm <[EMAIL PROTECTED]> wrote: >The real problem is due to contact bounce at the key contacts. The firmware >cannot detect the closure on both the dot and dash lines at the same time, >but when one is detected, the other is checked to see if it is closed too - >now if the contacts are bouncing, at the exact time the opposite line is >checked, it occurs at a time that just happens to be during a higher voltage >part of the bounce cycle. > ...
I found the suggestion by Ed, KG4ARN (listed on LA3ZA's mods page) http://www.ac6rm.net/mailarchive/html/elecraft-list/2003-06/msg00979.html to add a 0.1 microfarad capacitor across the straight key or bug worked for me. The time constant for the paddle lines to come back high is set by the 220 ohm resistor and 0.001 microfarad capacitors in the key lines which gives a time constant of 0.22 microseconds. Adding the 0.1 microfarad capacitor across the key changes this to 22 microseconds. This seems like a reasonable value to me since a test in the controller should take about 2 microseconds; testing both the dot and dash lines sequentially should complete in about 4 microseconds. 73 Kevin w9cf _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
