TCXO / OCXO behavior differences

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Andrew,
Maybe Steve can comment on this but I wonder if there is a difference in the behavior since the 6500 has a TCXO (temp compensated crystal oscillator) and the 6700 has an OCXO (oven controlled crystal oscillator). Below is a partial snapshot from a document I compiled about the stability differences. It's a summary based on what I've been able to gather about the 6000 series but it has not been validated by Steve. The full document has some additional examples and notes. Let me know if you would like a copy.

The link below is to a good article that discusses the differences between TCXO and OCXO devices if you would like some additional details about the benefits of each.

http://www.radio-electronics.com/info...

Regards, Al / NN4ZZ

Note: This topic was created from a reply on the DC power to FLEX-6000 continuously? topic.
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Al / NN4ZZ

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Posted 6 years ago

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Al / NN4ZZ

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Here is the snapshot referred to in the initial post about the stability of the TCXO, OCXO and GPSDO options

Please note: the plus or minus numbers in the examples above are based on a frequency of 14.010 which is defined in the full document.

Regards, Al / NN4ZZ

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Steve - N5AC, VP Engineering / CTO

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Official Response
Al,

1. I believe your math is wrong on the FLEX-6700 OXCO -- 20ppb would be +/- 280mHz, not 700mHz at 14.01MHz
2. On the GPSDO, at 5 minutes, the spec is 10ppb accuracy (140mHz) and after 24 hours it is 0.005ppb -- note ppb not ppm (70uHz [microHertz] at 14.01MHz).
3. Just for reference, on the GPSDO with no antenna attached, the spec is 150ppb (2.1Hz at 14.01MHz)

So on a FLEX-6500 with a GPSDO with no antenna, you are still better off leaving the GPSDO on ("installed" in software), but on the FLEX-6700 if you cannot provide the GPSDO an antenna, you are better off to "uninstall" it in software and force the radio to use the OCXO.

Steve
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Al / NN4ZZ

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Steve,
Thanks for the corrections and also the GPSDO recommendations. The 6700 OXCO is even better than I thought. It sounds like until/unless I have a need for the even better stability of the GPSDO, the OCXO on the 6700 will be fine for me. Especially since I can add the GPSDO later if needed.

If you don't mind and have time to review it, I'd like to send you my full updated document in a day or so to see if I have any other errors.

Regards, Al / NN4ZZ