Good one, the HP58503A, actually it is my reference at work. On Fri, Sep 7, 2012 at 10:37 PM, <[email protected]> wrote:
> Hello Robert, > > your question is like asking which car you should buy, or which airline you > should fly :) > > Everyone will have a different answer. > > But I do not recommend the Thunderbolts, it's a crab-shoot with them > (different versions have different performance, the new ones are actually > worse > than older versions because of the temperature chip issue, the GPS is > known > to have lock issues, they don't work well until you spend a lot of time > fine-tuning the parameters, etc etc) - that has all been discussed here > ad-infinitum and you can find it in the archives. > > I recommend you search Ebay for HP 58503A. I just bought a number of them > from a very well known seller in China, and they are absolutely superb, > much better than any Rubidium unit I have tested. Much better than the > Thunderbolt I have, and just slightly more expensive. He sells an entire > kit for > around $500, and it arrived here in less than a week (Northern > California). > > This seller starts those units at around $260 I think. Performance you can > get from these if you get a good one is: phase noise floor of around > -163dBc, ADEV of 7E-013 to about 1E-012 to over 100s. Leapsecond.com has a > number of test papers on these units. Caveat-emptor: there are significant > unit-to-unit variations as with all GPSDO, Tom on leapsecond.comdiscusses this > in detail. BTW: these are essentially the same unit as the Z3801A, just > different software (ID string). > > I also have a Z3815A, and it is not even in the same class as the > Z3801A/58503A. It is very noisy compared to the 58503A unit. I do not > recommend the > Z3815A, but it is a unique oscillator design,and some folks collect it for > that oscillator. The 58503A uses a double oven version of the HP 10811A, > which is a fantastic oscillator if you get a well-working one. > > If you want something low-cost with reasonable performance, brand new with > warranty, antenna, and accessories, Jackson Labs Technologies, Inc. has > the GPSTCXO eval kit for Time-Nuts special academic pricing of $300, which > we > believe is the lowest-cost true GPSDO (not NCO) in current production. > Disclaimer: I work for them. > > bye, > Said > > > > > In a message dated 9/7/2012 13:09:24 Pacific Daylight Time, > [email protected] writes: > > Welcome aboard, > yes, there is no FAQ about how to start in this hobby... should I try to > implement one? Anyway, start with a Trimble Thunderbolt (aka TBolt), later > you will know why it is highly recommended (direct OCXO disciplining and > LH > software support, mainly). I have a Z3815A with the famous (or infamous) > E1938A "hockey puck" OCXO. They are all GPSDOs and there should not be any > difference among them but, yes, there are differences in their performance > and being a time-nut means test and find out. Then there are GPS > disciplined Rubidiums, but take this step after the first GPSDO is > correctly installed and stabilized. Start with the antenna: find a > suitable > place, with a 360 deg clear view of the sky, a satellite TV cable (sounds > unusual, but works great). > > On Fri, Sep 7, 2012 at 8:52 PM, Robert Darlington > <[email protected]>wrote: > > > You want to start with a GPSDO. I like the Trimble Thunderbolt. The > > price is right and they're readily available. I have no experience > > with the HP units but they seem to be highly regarded. > > > > Rb oscillators are great for some things, but need to be calibrated. > > That's where the GPSDO comes in. > > > > Also, don't forget the antenna. You'll want something along these > > lines: > > > > http://www.ebay.com/itm/lucent-GPS-Timing-Reference-Antenna-antenne-40db-N-/230848464732?pt=GPS_Antennas&hash=item35bfa4075c#ht_2199wt_1404 > > > > Welcome aboard, and I'm apologizing in advance for how much money > > you'll be spending on new toys. > > > > -Bob > > _______________________________________________ > 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. > _______________________________________________ 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.
