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Sunday, 17 November 2013

Man with two watches...

....never know correct time.

Because of this syndrome the correct thing for me to do now that I have established the GPS disciplined OCXO from here:

http://g0mgx.blogspot.co.uk/2013/11/gps-disciplined-really.html

Is to simply use this as the master frequency reference and calibrate everything else against it.

If I went ahead with my plan to use the GPS 1pps signal for a frequency counter, imagine the dilemma if they didn't agree! The GPS Disciplined OCXO uses some complex averaging to ensure that an out of sync 1pps pulse due to an aeroplane passing overhead or the washing machine (the second item isn't a likely cause; I am just checking you are paying attention) are not acted upon. Using the 1pps signal to gate a frequency counter wouldn't be able to do this.

So, to cut a long story short I have taken the frequency counter I first started here:

http://g0mgx.blogspot.co.uk/2011/07/pic-n-choose-how-to-count.html

And have calibrated it against the GPS OCXO:



So, all in all I am very pleased with the results of this project. I have learned a great deal and have a very accurate frequency reference and a counter to go with it. From conception to finish the counter project has only taken 2 years and 4 months!

Another great homebrewed addition to my RF workbench.

Good, egh?

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