Jerry, Chris, it's all relative, while the Lpro may be a good Rb standard, it's phase noise is not that good really. You list: -96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz offsets For the Lpro. The new Jackson Labs Technologies LN CSAC GPSDO with SC-cut phase noise and ADEV filter achieves the following: -138dBc/Hz @ 10Hz, -148dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz offsets. At 1Hz offset we see -105dBc/Hz and better on that unit. The FEI-5680A Rubidium that we discussed here some time ago has a much worse phase noise plot of course, because the 10MHz is generated digitally through a DDS, not a 10MHz crystal oscillator.. It all depends on your requirements, and your budget.. I think the Z3801A (or it's brother the 58503A) is still one of the lowest phase noise and best ADEV GPSDO on the surplus market if you get a typical unit, and if you can locate one. bye, Said From: Jerry Mulchin <[email protected]_ (mailto:[email protected]) > Date: June 2, 2012 16:44:14 PDT To: Discussion of precise time and frequency measurement <[email protected]_ (mailto:[email protected]) > Subject: Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie). Reply-To: Discussion of precise time and frequency measurement <[email protected]_ (mailto:[email protected]) >
Chris, To answer your question regarding using a Rubidium standard as a frequency reference for your Transverters. GPS really has nothing to do the main requirement regarding Phase Noise and your Transceivers. But the 10MHz oscillator inside the Rubidium standard is the item that will be the Phase Noise problem if you get the wrong Rubidium standard. There are cheap Rubidiums and there are good Rubidium standards to consider. An LPRO-101 is actually a very good Rubidium standard, and exhibits Phase Noise values of -96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz offsets from carrier. This is what I use for my 10GHz Transverter reference, but I don't lock it to GPS when in the field. LPRO-101's can be gotten pretty reasonably. Locking the LPRO-101 to a GPS will require more support circuitry, and most of the folks on this list can help you with that. Also, Thunderbolt GPS disciplined units are nice, but I do not know the Phase Noise numbers of a typical Thunderbolt unit. Others here probably know the answer to that. The important thing to remember is you don't what to use 10MHz oscillators that have poor Phase Noise performance as it will effect your weak signal capability if you use a poor Phase Noise oscillator. Jerry At 03:05 PM 6/2/2012, you wrote: If you want a frequency reference. There is nothing better than GPS. In fact it you bought a Rubidium you would still need the GPS so you could calibrate its frequency. Some GPSes might be noisy but then you can lock a good double oven crystal oscillator to it and have what they call a "GPS disciplined crystal oscillator or "GPSDO". On Sat, Jun 2, 2012 at 2:57 PM, Chris Wilson <[email protected]_ (mailto:[email protected]) > wrote: I am looking to get a frequency standard for my amateur radio shack, initially for verifying test gear readings, but later as a standard to lock receiver and transmitter oscillators to. I was going to buy a GPS frequency standard but a friend warned me these may have noise issues when I come to use it with an oscillator in RX / TX applications. It's not something I had considered, so what's the score here please? Should I not buy a GPS standard? Thanks. Any links to known safe suitable purchase sources from personal experience welcome, either here or by PM or e-mail. I am in the UK. -- Best regards, Chris Wilson _mailto:[email protected]_ (mailto:[email protected]) _______________________________________________ time-nuts mailing list -- [email protected]_ (mailto:[email protected]) To unsubscribe, go to _https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts_ (https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts) and follow the instructions there. -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected]_ (mailto:[email protected]) To unsubscribe, go to _https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts_ (https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts) and follow the instructions there. Jerry Mulchin _______________________________________________ time-nuts mailing list -- [email protected]_ (mailto:[email protected]) To unsubscribe, go to _https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts_ (https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts) and follow the instructions there. = _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
