Re: OT 10Mhz references


Hi Ancel,
300Hz wide bandwidth at 25C has -149dBm noise power. That would be the theoretical thermal noise floor.
-130dBm should be doable with the practical noise about -10dB down from there. How much room you get between the SA noise floor and -130dB will depend on the SA.

Dennis Tillman W7PF

-----Original Message-----
Sent: Sunday, March 13, 2016 9:38 AM
Subject: [TekScopes] Re: OT 10Mhz references

Yes, well I don't have the $$ for a GPSDO right now so I am going the DIY way wth a Trimble OCXO 65256 12V, 10MHZ sine.
It'll certainly be around 2 orders better than the internal TCXO in the SA or VNA. Improved Phase noise as well no doubt.
I don't know if I'll see a better noise floor on the instruments as a result. On the SA I can get down to around -149dBm/Hz median with a 1Mhz span and 300Hz VBW. A 3 dB 'noise' variance is visible from sweep to sweep. SO I'd imagine I could consider measuring a -140dBm/hz noise value as discernable. -130dBm should be easy to see.
Posted by: AncelB <>

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