Re: [time-nuts] Best Rubidium Frequency Standard

Poul-Henning wrote: At least some of the firmware versions do not allow you to change the PPSIN offset second by second, so you cannot compensate for the "negative sawtooth", and the resulting "hanging bridges" means that you have to us a very unoptimal PLL time constant. The cure for that is

Re: [time-nuts] Best Rubidium Frequency Standard

In message , Bob Camp writes: >Even if they do take the correction, do they want it before or after the >PPS comes along? If you have a destination device that wants it before >the pps and a GPS that gives it to you after the PPS ... that's

Re: [time-nuts] Best Rubidium Frequency Standard

Hi Even if they do take the correction, do they want it before or after the PPS comes along? If you have a destination device that wants it before the pps and a GPS that gives it to you after the PPS … that’s a bit of a problem. Bob > On Mar 13, 2016, at 12:07 PM, Poul-Henning Kamp

Re: [time-nuts] Best Rubidium Frequency Standard

In message <1e2b85.da47c0.4416d...@aol.com>, KA2WEU--- via time-nuts writes: >what is wrong with the Standford Research Rubidium standard with a 1 >sec sync pulls form a GPS satellite ?" At least some of the firmware versions do not allow you to change the PPSIN offset second by

Re: [time-nuts] Best Rubidium Frequency Standard

Hi > On Mar 13, 2016, at 10:22 AM, ka2...@aol.com wrote: > > Good morning , > > what is wrong with the Standford Research Rubidium standard with a 1 sec > sync pulls form a GPS satellite ?” The second to second variation in the pps from a normal GPS receiver is in the > 20 ns range. If

Re: [time-nuts] Best Rubidium Frequency Standard

Hi > On Mar 13, 2016, at 4:37 AM, Iain Young wrote: > > Hi, > > OK, so I'm about to show the limitations of my knowledge :) > > Bob Wrote: > > On 11/03/16 22:51, Bob Camp wrote: > >> If your target is something like a microwave radio, many Rb’s are > > “challenged” in terms

Re: [time-nuts] Best Rubidium Frequency Standard

Hi Ok, so I can spend $2,500 on a working 5065A if I can find one. I can spend the same money on five working FRK’s at $500 (if I can find them). I can spend the same money on 10 working PRS-10’s (if they show up). I can spend that money on 40 working with a warranty telecom Rb’s right at $125

Re: [time-nuts] Best Rubidium Frequency Standard

Good morning , what is wrong with the Standford Research Rubidium standard with a 1 sec sync pulls form a GPS satellite ?" Ulrich In a message dated 3/13/2016 10:16:11 A.M. Eastern Daylight Time, kb...@n1k.org writes: Hi With “real” (who knows how real) Rb based GPSDO’s selling

Re: [time-nuts] Best Rubidium Frequency Standard

Hi With “real” (who knows how real) Rb based GPSDO’s selling below $250, it’s not clear that running an Rb in a lash up that makes it look like a TBolt is a worthwhile exercise. Unless you can get the time constants out into the “several days” range, a manual adjust is a much better way to go.

Re: [time-nuts] Best Rubidium Frequency Standard

Hi, OK, so I'm about to show the limitations of my knowledge :) Bob Wrote: On 11/03/16 22:51, Bob Camp wrote: If your target is something like a microwave radio, many Rb’s are > “challenged” in terms of phase noise and/or spurs. Some sort of > cleanup will be needed for almost all of them.

[time-nuts] Best Rubidium Frequency Standard

In many ways the 5065A is the probably the most repairable of all the units (closely followed by the FRK family and the M100). They all use parts that are mostly still available and the circuitry is accessible. You can assume that the lamp (and maybe some of the microwave parts) in any Rb

Re: [time-nuts] Best Rubidium Frequency Standard

I'd be curious in knowing what the correct settings to discipline a prs 10 are, even pointers and hints would be very welcome. I was never very happy with the performance of mine in that configuration vs simply letting it free run and periodically re syncing it (via the one pps input.) All

Re: [time-nuts] Best Rubidium Frequency Standard

I wrote: With the right settings, a PRS10 *does* work extremely well with the PPS input from a GPS. They do generally take several days or more to lock, because of the long time constants involved. Bob replied: I would call having to wait a few days for it to lock a bit of a disadvantage.

Re: [time-nuts] Best Rubidium Frequency Standard

Bert, Bob, Charles, Corby, Eric, Luciano, Mark, Rob, . . . Thanks for the excellent advice. It has been very helpful. Let me see if I can summarize what different people are saying. 1. The absolute best rubidium standard is the HP 5065A. It has excellent short term stability. The only

Re: [time-nuts] Best Rubidium Frequency Standard

jerry wrote: Is there any model-suffix or other identifier that would inform whether a used PRS-10 has the PPS sync input feature?? Not that I am aware of. Not even the "customer part number" is a reliable guide -- I have had several examples each of various CPNs, and some did have the

Re: [time-nuts] Best Rubidium Frequency Standard

Hi > On Mar 12, 2016, at 6:11 PM, Charles Steinmetz wrote: > > jerry wrote: > >> Is there any model-suffix or other identifier that would inform whether a >> used PRS-10 has the PPS sync input feature?? > > Not that I am aware of. Not even the "customer part number"

Re: [time-nuts] Best Rubidium Frequency Standard

Hi If you dig into the modern GPS Rb’s they put the 5065 to shame. They are also don’t seem to show up on eBay …. Bob > On Mar 12, 2016, at 4:50 PM, Bruce Griffiths > wrote: > > The ultimate solution to this conundrum is to roll ones own Rubidium standard > to

Re: [time-nuts] Best Rubidium Frequency Standard

The ultimate solution to this conundrum is to roll ones own Rubidium standard to achieve performance beyond the HP5065A e.g.: https://doc.rero.ch/record/32317/files/2318.pdf Bruce On Saturday, March 12, 2016 01:46:29 PM Bob Camp wrote: > Hi > > Another example of the “stored in magic

Re: [time-nuts] Best Rubidium Frequency Standard

To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Best Rubidium Frequency Standard Mike wrote: >4. The PRS-10 can handle the GPS synchronization simply by feeding the > GPS 1 pps signal to it. That eliminates a lot of secondary > effort needed to &g

Re: [time-nuts] Best Rubidium Frequency Standard

Hi Another example of the “stored in magic memory” issues on some modern Rb’s: To improve the yield of Rb’s cells, a DDS can be used to tune a bit one way or the other off of the normal resonance frequency. The reasons why they are off are a bit involved, the fact is they do get manufactured

Re: [time-nuts] Best Rubidium Frequency Standard

Corby the M100 have conformal coatings but non of the M100's that I have tested had potted Lamp modules. Conformal coating is a pain but so far all we have worked on is the coil section and scraper and brass brush did do the job. will send you off list pictures of a bad disassembled lamp

Re: [time-nuts] Best Rubidium Frequency Standard

Any one have any experience with the Symmetricom Militarized 8130A Rubidium? An update to a M100? Thanks. Jim Robbins N1JR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

Re: [time-nuts] Best Rubidium Frequency Standard

Having used FRK for over 35 years I am partial to FRK/M100. More later. We have had some bad experience with PRS-10 failing lamp module and others have shared the same observation. Clear sign of oxidation and we know the unit has never been exposed to water! Back to FRK. Previously mentioned

[time-nuts] Best Rubidium Frequency Standard

Mike, If you are planning to buy "suspect units" with the intent to repair I would steer clear of the PRS10. It is true you can pay for a factory repair but having the schematics and theory of operation only helps for particular repairs. This is because a lot of the alignment parameters are

Re: [time-nuts] Best Rubidium Frequency Standard

Hi The PRS-10 generally shows up in versions that do not have the external pps input working. Even on the ones that *do* have a pps, it is not one that works well with the pps from a GPS. Simply put, that option is not worth spending money on. Manually adjusting an Rb against a GPS is a bit

Re: [time-nuts] Best Rubidium Frequency Standard

Joseph, There are a few data points that lead to this conclusion... 1. Look at the images on eBay for various PRS-10 and TSD-12 auctions. You will see that they all have the same customer part number 143-44101-xx where xx is 04, 08 or 10. Further, you will find a PRS-10 and a

Re: [time-nuts] Best Rubidium Frequency Standard

Mike wrote: 4. The PRS-10 can handle the GPS synchronization simply by feeding the GPS 1 pps signal to it. That eliminates a lot of secondary effort needed to get the disciplining up and running. That would minimize both the cost and effort. Control of both the PRS-10 and

Re: [time-nuts] Best Rubidium Frequency Standard

> Or, perhaps not. The two working TSD12s that I see on eBay (apparently > the same as the PRS-10 except the lock flag is set to 3 instead of 1 and > which can be reset) Would you elaborate on this? I Googled for TSD12 and except for the auction listings, found nothing. Joe

Re: [time-nuts] Best Rubidium Frequency Standard

Bob, After all of the excellent feedback here, my current thinking is that I can get a parts / repair PRS-10 for somewhere near $150. There are several reasons that this might be the best option... 1. It appears to be about the best that I can afford from what I have seen of the testing

Re: [time-nuts] Best Rubidium Frequency Standard

HI None of this is a simple slam dunk. The 5065 has great ADEV numbers. In “as delivered” condition It has horrid TC and pressure sensitivity. It also is > 10X more expensive than a lot of the other devices. The units that *can* be disciplined are rarely set up to do so properly off of a

[time-nuts] Best Rubidium Frequency Standard

Mark's Law of Rubidium Goodness... the bigger the box, the better it is. The HP5065A is one of the best units ever made. It can rival a cesium beam unit. The X72 is a horrid little creature. I would also go with the M100 / FRK units. The LPRO an FE56xx units were designed for telecom use

Re: [time-nuts] Best Rubidium Frequency Standard

I have been running an M100 for over 15 years. It was NOS when I purchased it for $300. Runs 24x7, and just keeps chugging along. Rob NC0B Sent from my iPad > On Mar 11, 2016, at 10:01 AM, "time...@metachaos.net" > wrote: > > > > Luciano, > > Why? Why the Efratom

Re: [time-nuts] Best Rubidium Frequency Standard

Luciano, Why? Why the Efratom FRK or M100 over the Efratom LPRO-101? The M100 appears to be manufactured in '91. Given the limited lifespan, why such an older choice? I didn't list the HP5065A because I didn't see it on eBay. What makes it better than the others? Why not one of the Symnmetricom

Re: [time-nuts] Best Rubidium Frequency Standard

I'd never heard of the SRS TSD-12 until I saw it on your list. It looks like a SRS PRS-10 with the connector in a different location but I don't know if they are close in performance or not. you might want to take a look at the PRS-10 anyhow since it appears to have excellent performance numbers;

Re: [time-nuts] Best Rubidium Frequency Standard

Hi Mike, You have not mentioned the best Rubidium available, the HP5065A. Last week two of them are sold on ebay. Second chose can be the Efratom FRK or M100, than all the others. Luciano On Fri 11/03/16 12:02 , time...@metachaos.net wrote: > Hi, > > In looking at eBay, I current see

[time-nuts] Best Rubidium Frequency Standard

Hi, In looking at eBay, I current see quite a few different types of rubidium frequency standards. I have seen some of these mentioned here, but no real comparisions. The question, is what are the pros and cons of these specific models? Which ones are best or most reliable? Which ones cannot be