[Elecraft] Time Syncronization

Jim Brown jim at audiosystemsgroup.com
Wed Sep 13 17:40:32 EDT 2017


Lynn,

You can argue all you like, but those with long experience with WSJT 
modes try to keep their clock within a few tens of msec of correct time. 
Why?  Because the other station can be off in the other direction, and 
what counts is the DIFFERENCE between you and the station you're trying 
to work. And the greater that difference, the less likely that you will 
decode each other, especially under weak signal conditions. Why?  
Because the noise reduction schemes for JT65, JT9, and FT8 are 
synchronized to the beginning of the transmission period, and the 
decoding station needs to lock onto the sending station.

Time sync is LESS critical for modes like MSK144 and ISCAT, which are 
primarily used for meteor scatter, decode from short bursts of signal, 
and do not depend on sync for their decoding.

73, Jim K9YC

On 9/13/2017 1:38 PM, Lynn W. Taylor, WB6UUT wrote:
> Plus or minus 500 msec. isn't a big deal.  It's big enough that I'd 
> argue that it's essentially the same.




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