1pps for ice tube clock kit

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kc2ttt
 
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Joined: Sat Oct 19, 2013 6:57 pm

1pps for ice tube clock kit

Post by kc2ttt »

would someone be able to help with adding a 1pps input to the ice tube clock kit? I have a dual oven gps ref for my test gear and would like to sync it, i saw a user of another product used one of the microprocessor pins to measure the freq. or something to have it track, my clock loses about 15-30 seconds a week. I know i can trim the crystal in but the sync would be better.

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jarchie
 
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Re: 1pps for ice tube clock kit

Post by jarchie »

This isn't exactly what you're describing, but you might want to take a look at my xmas firmware. There are a number of options for software-based compensation for time drift, GPS synchronization, and temperature compensated timekeeping.

The large drift you describe is typical of a correctly assembled Ice Tube Clock kit. If you swap out the 20 pF caps for 10 pF caps, the clock is almost dead-on accurate.

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wildtang3nt
 
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Joined: Thu Aug 09, 2012 2:31 pm

Re: 1pps for ice tube clock kit

Post by wildtang3nt »

I can attest to jarchie's claim. Even just swapping the XTAL filter caps as he says makes a measurable improvement in the stock firmware, it was the first mod I did. However, dropping in a 328 and switching to his firmware means <15s drift/year in my experience using it for almost three years now. It is currently running 2s slow, I can't remember when I last bothered to correct it.

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