I have built 4 of the OCXO, how did you set the OCXO up? Mine are all inside a qrp-labs.com case with no issues.
I used Argo software and a FT 817ND as receiver with a lead from spk out on the 817 to mic in on laptop, set u3s to tx fskcw as stated in manual and watch the signal frequency in Argo drop then stabilise. At some point it will rise, this is too far,back off a touch and you will be fine. My OCXO u3s don't drift although sometimes a spot may say -1.
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