Re: [time-nuts] Trimble copy of Z3801
All the the Nortel Tbolts had DOCXO but not the regular Tbolts or the 1/2 Tbolts that have been purchased through time-nuts (though they are nice too). A few lucky people got the ATT bolts (VERY RARE) which have the nice OCXO too but with extra stuff on the board. These nortel tbolts are much nicer because of the DOCXO which is a much taller package than what's found in the standard Tbolt and the 911 Tbolts. The Oak/McCoy are the same as the Corning which eventually became the Vectron OC-050 (because of buyouts) which is what this one up for auction probably is relabeled as trimble of course. I'm not sure about this one but I know some of these nortel Tbolts talk SCPI just like the Z3801 but not the same commands as the Z3801. -- From: Bob Camp li...@cq.nu Sent: Tuesday, October 27, 2009 20:48 To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Trimble copy of Z3801 Hi All of them had double ovens. They came from a variety of suppliers. Vectron / Norwalk was the original source. At various times they came from Oak / McCoy, PTI, and possibly CMAC. Bob On Oct 27, 2009, at 12:31 PM, theinfamousfla...@hotmail.com wrote: It's a double oven oscillator (vectron I believe) as opposed to the 1/2 tbolts that only have a single oven that everyone else has from the 911 units. This one has other additional features like full power supply conditioning (just add 48v power supply) and can have firmware upgraded. They're pretty nice. There is another version that has an even nicer DOXCO. Need a rs485 convertor though. can't connect rs232 directly -- From: John Green wpxs...@gmail.com Sent: Monday, October 26, 2009 16:10 To: time-nuts@febo.com Subject: [time-nuts] Trimble copy of Z3801 There is what appears to be a Trimble copy of a Z3801 on eBay. number 370234484785. I can't seem to find any info. Is this really a Z3801 copy or just a Tbolt in a fancy case? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Trimble copy of Z3801
It's a double oven oscillator (vectron I believe) as opposed to the 1/2 tbolts that only have a single oven that everyone else has from the 911 units. This one has other additional features like full power supply conditioning (just add 48v power supply) and can have firmware upgraded. They're pretty nice. There is another version that has an even nicer DOXCO. Need a rs485 convertor though. can't connect rs232 directly -- From: John Green wpxs...@gmail.com Sent: Monday, October 26, 2009 16:10 To: time-nuts@febo.com Subject: [time-nuts] Trimble copy of Z3801 There is what appears to be a Trimble copy of a Z3801 on eBay. number 370234484785. I can't seem to find any info. Is this really a Z3801 copy or just a Tbolt in a fancy case? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Double-Oven Thunderbolt on Ebay
Does anyone have a double-oven thunderbolt like the one that's now listed on ebay? If so, do you have any phase-noise or other performance data on it? -Flavio ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Dranetz meter
Where did you get the batteries? - Original Message - From: Stanley Reynolds [EMAIL PROTECTED] To: time-nuts@febo.com Sent: Friday, May 16, 2008 14:11 Subject: [time-nuts] Dranetz meter Found what I considered a deal on a 646 Dranetz meter, it has plenty of inputs, 3 phase, single phase A/C, and one each 200VPK A/C, 100VDC inputs. Dial-in modem, RS232, and Printer interfaces for logging. It appears to be working well but I had to look inside, found 3 leaking AA nicad cells on the CPU board and 12 more in a battery pack that needed to be replaced. This is just a reminder to look for leaky batteries inside all your older stuff like computers and desktop digital multi-meters before you have a toxic mess. 15 batteries at $1.25 each not too bad to keep acid off the circuit boards. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] WIRED Time Nuts, NPR
I think you did great! It's too bad you didn't have more time (ironically) to talk about other stuff. I never heard these Bryant Park people before but they sound more like ipod techies more than, true, engineering techies-- it's all good though. - Original Message - From: Tom Van Baak [EMAIL PROTECTED] To: John Ackermann N8UR [EMAIL PROTECTED]; Rick Karlquist [EMAIL PROTECTED] Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, December 18, 2007 15:20 Subject: Re: [time-nuts] WIRED Time Nuts, NPR Following the WIRED article, here's an NPR time nuts interview: http://www.npr.org/templates/story/story.php?storyId=17345235 Not sure it came out quite right; I can see now that talking live with off-the-wall questions is a bit more difficult than slowly composing/editing email or web pages. Also next time I'll get them to pronounce my name right! /tvb (Van Baak: rhymes with JS Bach, or clock). - Original Message - From: Tom Van Baak [EMAIL PROTECTED] To: John Ackermann N8UR [EMAIL PROTECTED]; Rick Karlquist [EMAIL PROTECTED] Cc: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, December 10, 2007 11:20 PM Subject: [time-nuts] WIRED Time Nuts Hi John Rick, Looks like Quinn's WIRED magazine time-nuts article was just released... Article: http://www.wired.com/science/discoveries/news/2007/12/time_hackers Photos: http://www.wired.com/science/discoveries/multimedia/2007/12/gallery_time_hackers Index: http://www.wired.com/science/discoveries /tvb http://www.LeapSecond.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 5087As for sale
How much do you want for each and/or all three? -Flavio - Original Message - From: Chuck Norton [EMAIL PROTECTED] To: Time Nuts List Time-nuts@febo.com Sent: Saturday, March 31, 2007 00:06 Subject: [time-nuts] HP 5087As for sale I have 3 of the HP 5087A Distribution amplifiers that I am going to sell. I thought I would offer them to the list members first. All are in really nice condition. They were excessed from one of the Colorado Agilent sites that has been down sizing. All three have the single input board, 12 output boards and are made for 10Mhz distribution. That would be option 033. All 3 of them work great. I have not tested all of the specs but have input a 1.247V, 10Mhz from my cesium and measured the output on all jacks. I have rack ears for each of them if you want them. If you are interested, contact me offline at the email address above and I will get you the details on them. I am located in Colorado Springs, Colorado USA Thanks Chuck Norton ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Government Liquidation
Like jshank, it is a real buyer beware sort of deal even if you can inspect things in person. If you have a problem, the customer service is the worst! You have to wait two weeks for an answer sometimes. Even if your dispute is serious, you may not even have a chance to appeal their decision. The last I checked, you'll loose 25% of what you pay (which is 10% to 18% higher than what your winning bid is because of taxes and auction fees) if you show up and the lot isn't what you thought it was and you decide not to take it. Another time, I've seen their employees remove items from a lot AFTER the auction closed but before the winning bidder picked them up. When I questioned them about it, they said that some pieces were incorrectly classified and had to be removed. So I asked them what they would do when the buyer sees those items missing, the guy actually told me that IF the buyer sees them missing, that they would work out some sort of deal! (IF buyer noticed) There is all sorts of paperwork that's a pain if you buy classified sales where the stuff they get is from classified projects. Many of the items have been sitting on the shelves for years. I bought one piece a while ago, it was classified as a working item, but when I opened it up, everything inside was corroded from exposure to salty sea air. Another big thing to watch out for is if something is listed in one place in the auction but not in the auction title, it may not necessarily be in that lot! My advise to the brave at heart, real ALL the contract docs and fine print all over the website to understand the fees and auction rules. AND you MUST inspect the pieces. They keep a log of who inspected what lot, and if you didn't inspect that lot in person and you have a problem--you won't have a leg to stand on when trying to file a complaint. Like jshank says, this was a good deal a few years ago, but people are willing to pay way too much for stuff they have no idea if it works -Flavio - Original Message - From: jshank [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, March 19, 2007 12:24 Subject: Re: [time-nuts] Government Liquidation Hi, I have bought items from this site on and off over the years as well as directly form military DRMO. You really need to go to the site to preview the item prior to purchase. You will be surprised how good the items looks in the picture as opposed to what it actually looks like in person. Be prepared to spend several hours getting into and out of some bases with the current security in place. On a recent purchase of two 2465b which were advertised as powering up I found that neither would display a trace, in fact one was completely gutted of all the hybrid chips. Even if I would have previewed these scopes I would have been unable to look inside as usually when viewing items you are escorted by a security personal, look but don't touch. It is incredible how high these items go when consideration all of the risks of buying. As little as ten years ago you could regularly pick up bargains and if the unit worked it was a great deal and if it did not it was a fair price for a parts unit. Hope my experiences help. Jeff - Original Message - From: Jason Rabel [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Monday, March 19, 2007 11:12 AM Subject: [time-nuts] Government Liquidation This is kind of on the same topic as the government surplus chit-chat... Just curious but has anyone bought stuff from the website: www.govliquidation.com I just started looking at it last night, they have a ton of stuff and right now everything has zero bids. I don't know if people all snipe at the last second or what. Thoughts / Opinions? Jason ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Need some help with Motorola Oncore VP Back in Binarymode
I don't think an 8 channel board will work with a Z3801A. -Flavio - Original Message - From: Don Garlick [EMAIL PROTECTED] To: time-nuts@febo.com Sent: Friday, March 09, 2007 17:37 Subject: [time-nuts] Need some help with Motorola Oncore VP Back in Binarymode Hello I need a little help I bought a Oncore VP board with 8 channels for my Z3801 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemitem=250082966589sspagena me=ADME:L:RTQ:US:1 Motorola P/N: B8221Z1116 This has a battery in it. It was tested by the seller by placing in the NMEA mode and left it in NMEA mode. Now the board he used to talk to it has failed so he cannot change it back. After I could not get it to work I tried draining the battery down to .07 volts. I still could not get it to work in the Z3801 Put the old 6 channel back in and it works again http://gps.garlickfamily.org Can anyone tell me how to get it out of NMEA and back to binary? Thank You Don ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 5087A manual -- or gain adjustment instructions?
Think it's up on Agilent's website. - Original Message - From: John Ackermann N8UR [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, March 03, 2007 10:04 Subject: [time-nuts] HP 5087A manual -- or gain adjustment instructions? Hi -- Anyone have a manual for the 5087A distribution amplifier? Failing that, I'm looking for information on how to set the input and channel gain -- mainly, the balance between the two. Thanks, John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Thunderbolt
Actually, from what I understand there is no power conditioning board. A regular Thunderbolt has two boards. A processing board and a power conditioning board stacked on top of each other. The power condition board is whole bunch more that just a DC-DC converter. These 1/2 Thunderbolts need alot of external conditioning. You cannot just hookup a switching power supply from Lamda or whatever. You need to spend alot of time and money to get these boards powered up with clean, stable power. That's just the power. I don't even want to think about other issues this things might have. A standard Thunderbolt is worth much more than one of these. I wouldn't think of buying one of these unless I was willing to spend a long time (and money) building the power supplies. Remember it's got to be stable as well as clean-- a couple of hijacked computer power adapters ain't gonna cut it. -Flavio - Original Message - From: Jason Rabel [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Saturday, March 03, 2007 22:28 Subject: Re: [time-nuts] Thunderbolt TVB bought one of the units off eBay and was going to report in once he got a chance to test it out. I think we have decided to put the purchase 'on-hold' until the seller decides to drop the price significantly. The biggest issue seems to be the missing DC-DC converter board, which provides a lot of line filtering and power stability for the rest of the unit. Without it the asking price is too high considering we are the main market demand, the unknown condition of the units, and most people seem to just want one to 'tinker' with. I just looked on eBay, and the seller has 20 units with zero purchases. He is including a DC-DC unit, but it appears to be for powering more than just the thunderbolt as the amp ratings are very high and the box is like twice the size of the thunderbolt (not exactly compact). If I'm stepping out of line, please someone speak up and feel free to smack me upside the head. Jason Is the group purchase of the thunderbolt GPSDO still in the works? WA4DFS Ed ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Important RTFG interface information
Pins 1 and 5 on each unit control the failover functionallity. If you disconnect them entirely on both the XO and RB units, both units will be in ON mode. But it will be interesting to see what happens when it goes only one way. - Original Message - From: John Ackermann N8UR [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, February 27, 2007 17:27 Subject: [time-nuts] Important RTFG interface information I just acquired the mysterious interface cable that goes between the RTFG-m-XO and RTFG-m-RB units. I have suspected that it wasn't a simple crossover cable, because the results I've seen with my homemade crossover haven't made a lot of sense. Here's the scoop: the interface cable is a simple DB-9 to DB-9 ribbon cable with the ribbon flipped -- the striped side goes to pin 1 on the RB end, and to pin 5 on the XO end. We pretty much knew that. However, the conductor on the other edge of the ribbon (between pin 5 on the RB end, and pin 1 on the XO end) is BROKEN in the middle. So, there is NO CONNECTION between XO pin 1 and RB pin 5. (It goes without saying, but I'll say it anyway, that this means the cable ends are not interchangeable -- there is an XO end and an RB end.) Hope this is helpful. I got a few more interesting bits and pieces along with this cable, but I think this is the important news for those of us trying to interface these units at home. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request
1. Same test with a Fluke 6680 yeilds 10MHz mean exactly. 2.Tried different length cables and swapping the cables. Same result. 3. Autocal was done (a few times) - Original Message - From: Tom Van Baak [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 22, 2007 00:12 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request I have an SR620 counter that I set up with a Z3801A as an external reference. If I put a bnc T connector at the output of the Z3801A and use two equal length bnc cables, one to the ext. ref input on the back and the other to channel A then do a frequency measurement, I get a mean that is about .0015 Hz below 10,000,000.Hz. Does any know why this might be happening? I would expect it to read 10,000,000. exactly give or take a couple on the last digit. Three comments that may help. (1) 0.0015 Hz out of 10 MHz is 1.5e-10 which seems a little high but not too bad. But do not expect exactly 10 MHz with this sort of test. What you are giving to the channel A input is the most highly phase correlated signal you can imagine relative to the internal clock and the interpolators. This won't happen in real life with real input frequencies. (2) Try different lengths of the channel A cable and see if the number changes. My prediction is it will. (3) Run the setup menu self-calibration if you haven't in a while. /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request
I read the same spec on pg 63 but I read it as a fluctuation not an offset. I'm curious if you try the test Bruce suggested and set the gate time to 0.1s and then 0.01s and see if the offset increase by a factor of 10 for each change? I'm finding it hard to believe that this top of the line instrument can't handle this rudimentary task when my old Fluke 6680 with 500ps one shot precision (25 times slower than the SR620) handles it perfectly. I'm still not buying this offset is correct. - Original Message - From: Robert Crawford [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, February 21, 2007 23:13 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request I ran into this same problem with my first SR620. I thought it was defective, so I sent it to SRS for a cal and refurbishment. It got better, but still had an offset of 0.0004 Hz. Later I bought a second one, and it, too, had an offset similar to yours. A careful reading of the manual, page 63, Performance Tests, Accuracy (where the 10 MHz output from the back panel is measured at the A input) reveals that a +/- 0.0035 Hz offset on a 10 MHz input is acceptable and within spec. I think this also applies to your test configuration. I have a photograph of my two SR620s, both using an external clock (PRS-10/GPS from an FS710 Distribution Amp), and both measuring the same signal on their A inputs. One reads 10,000,000.00096 Hz and the other reads 9.999,999.99827 Hz. I used a gate time of 1 second averaged for 100 readings. Both SR620s had fresh factory calibrations. Bob Crawford [EMAIL PROTECTED] wrote: I have an SR620 counter that I set up with a Z3801A as an external reference. If I put a bnc T connector at the output of the Z3801A and use two equal length bnc cables, one to the ext. ref input on the back and the other to channel A then do a frequency measurement, I get a mean that is about .0015 Hz below 10,000,000.Hz. Does any know why this might be happening? I would expect it to read 10,000,000. exactly give or take a couple on the last digit. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request
Ulrich wrote that even with an external time base connected this calibration byte stays active and that you have to set it by hand I tried it, but on my unit calbyte 4 does not have an effect when the external timebase is connect, unlike yours. -thank Flavio - Original Message - From: Ulrich Bangert [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Thursday, February 22, 2007 11:24 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request Dear ???, I encountered pretty much the same effect when I bought my second hand SR620. As you, I have been extremly surprised by the fact that the counter did not display exactly 10.0 MHz under the conditions that you describe. However, the answer is in the software: The built in time base has a coarse gain adjustment screw (electronic adjustment) and the fine gain adjustment is done by calibration byte number 4 in the software. Please note that this calibration byte (in fact it is 12 bits) is NOT influenced by the autocal procedure so no wonder that autocal brought you no changes. It seems, that even with an external time base connected this calibration byte stays active and that you have to set it by hand to its most correct value as explained under point 5 of Calibration Procedure / Clock Oscillator Calibration on page 77 of the handbook. If you don't have the handbook available: You may download it (but missing the schematics) from the SRS web site. Best regards Ulrich Bangert, DF6JB -Ursprüngliche Nachricht- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von [EMAIL PROTECTED] Gesendet: Mittwoch, 21. Februar 2007 23:57 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] SRS SR620 External Source Issue -- Help Request I have an SR620 counter that I set up with a Z3801A as an external reference. If I put a bnc T connector at the output of the Z3801A and use two equal length bnc cables, one to the ext. ref input on the back and the other to channel A then do a frequency measurement, I get a mean that is about .0015 Hz below 10,000,000.Hz. Does any know why this might be happening? I would expect it to read 10,000,000. exactly give or take a couple on the last digit. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi- bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request
Bob, I see what your saying about the frequency error spec on pg vii, but I'm still reading as a fluctuation not an offset of the mean. In my mind, I don't see why there should be some sort of adjustment for this. I really doesn't make sense that the would make a counter that doesn't display a mean that is accurate. -Flavio - Original Message - From: Robert Crawford [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 22, 2007 11:58 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request Flavio, Your experience exactly parallels my surprise and disappointment when I bought my first SR620. In fact, that's why I bought my second one: I just couldn't believe the results, even though it had been freshly calibrated by the factory. However, the Specifications on page vii of the manual tells the story. The Frequency Error is listed as +/- ((100 ps typ) [350 ps max])/Gate + Timebase Error) x Frequency. If you make timebase error zero and use a 1 second gate, for a 10 MHz signal you get +/- 0.001 Hz, or +/- 0.0035 Hz max. For a 0.1 second gate, the typical error goes up to 0.01 Hz, which is exactly what you are seeing. I haven't played with the CALBYTE 4 value since I sent both of mine to SRS for calibration. If I remember right you need to move a jumper inside the unit to enable adjustment of this value, and I didn't want to break the factory calibration stickers. I thought this was simply the internal time base frequency adjustment. Bob Crawford [EMAIL PROTECTED] wrote: I read the same spec on pg 63 but I read it as a fluctuation not an offset. I'm curious if you try the test Bruce suggested and set the gate time to 0.1s and then 0.01s and see if the offset increase by a factor of 10 for each change? I'm finding it hard to believe that this top of the line instrument can't handle this rudimentary task when my old Fluke 6680 with 500ps one shot precision (25 times slower than the SR620) handles it perfectly. I'm still not buying this offset is correct. - Original Message - From: Robert Crawford [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, February 21, 2007 23:13 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request I ran into this same problem with my first SR620. I thought it was defective, so I sent it to SRS for a cal and refurbishment. It got better, but still had an offset of 0.0004 Hz. Later I bought a second one, and it, too, had an offset similar to yours. A careful reading of the manual, page 63, Performance Tests, Accuracy (where the 10 MHz output from the back panel is measured at the A input) reveals that a +/- 0.0035 Hz offset on a 10 MHz input is acceptable and within spec. I think this also applies to your test configuration. I have a photograph of my two SR620s, both using an external clock (PRS-10/GPS from an FS710 Distribution Amp), and both measuring the same signal on their A inputs. One reads 10,000,000.00096 Hz and the other reads 9.999,999.99827 Hz. I used a gate time of 1 second averaged for 100 readings. Both SR620s had fresh factory calibrations. Bob Crawford [EMAIL PROTECTED] wrote: I have an SR620 counter that I set up with a Z3801A as an external reference. If I put a bnc T connector at the output of the Z3801A and use two equal length bnc cables, one to the ext. ref input on the back and the other to channel A then do a frequency measurement, I get a mean that is about .0015 Hz below 10,000,000.Hz. Does any know why this might be happening? I would expect it to read 10,000,000. exactly give or take a couple on the last digit. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Possible Solution
I have been able to correct the offset problem. The solution fixed the offset problem for both channels A and B and all gate times. I've have written to SRS tech support to ask them if my solution is correct. I will post the solution once they reply-- I don't want people to start playing with there SR620's and then find out they are just screwing them up because of my solution Thanks for everyone's input, especially Bruce's gate time observation! - Original Message - From: [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 22, 2007 14:32 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request Bob, I see what your saying about the frequency error spec on pg vii, but I'm still reading as a fluctuation not an offset of the mean. In my mind, I don't see why there should be some sort of adjustment for this. I really doesn't make sense that the would make a counter that doesn't display a mean that is accurate. -Flavio - Original Message - From: Robert Crawford [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 22, 2007 11:58 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request Flavio, Your experience exactly parallels my surprise and disappointment when I bought my first SR620. In fact, that's why I bought my second one: I just couldn't believe the results, even though it had been freshly calibrated by the factory. However, the Specifications on page vii of the manual tells the story. The Frequency Error is listed as +/- ((100 ps typ) [350 ps max])/Gate + Timebase Error) x Frequency. If you make timebase error zero and use a 1 second gate, for a 10 MHz signal you get +/- 0.001 Hz, or +/- 0.0035 Hz max. For a 0.1 second gate, the typical error goes up to 0.01 Hz, which is exactly what you are seeing. I haven't played with the CALBYTE 4 value since I sent both of mine to SRS for calibration. If I remember right you need to move a jumper inside the unit to enable adjustment of this value, and I didn't want to break the factory calibration stickers. I thought this was simply the internal time base frequency adjustment. Bob Crawford [EMAIL PROTECTED] wrote: I read the same spec on pg 63 but I read it as a fluctuation not an offset. I'm curious if you try the test Bruce suggested and set the gate time to 0.1s and then 0.01s and see if the offset increase by a factor of 10 for each change? I'm finding it hard to believe that this top of the line instrument can't handle this rudimentary task when my old Fluke 6680 with 500ps one shot precision (25 times slower than the SR620) handles it perfectly. I'm still not buying this offset is correct. - Original Message - From: Robert Crawford [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, February 21, 2007 23:13 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request I ran into this same problem with my first SR620. I thought it was defective, so I sent it to SRS for a cal and refurbishment. It got better, but still had an offset of 0.0004 Hz. Later I bought a second one, and it, too, had an offset similar to yours. A careful reading of the manual, page 63, Performance Tests, Accuracy (where the 10 MHz output from the back panel is measured at the A input) reveals that a +/- 0.0035 Hz offset on a 10 MHz input is acceptable and within spec. I think this also applies to your test configuration. I have a photograph of my two SR620s, both using an external clock (PRS-10/GPS from an FS710 Distribution Amp), and both measuring the same signal on their A inputs. One reads 10,000,000.00096 Hz and the other reads 9.999,999.99827 Hz. I used a gate time of 1 second averaged for 100 readings. Both SR620s had fresh factory calibrations. Bob Crawford [EMAIL PROTECTED] wrote: I have an SR620 counter that I set up with a Z3801A as an external reference. If I put a bnc T connector at the output of the Z3801A and use two equal length bnc cables, one to the ext. ref input on the back and the other to channel A then do a frequency measurement, I get a mean that is about .0015 Hz below 10,000,000.Hz. Does any know why this might be happening? I would expect it to read 10,000,000. exactly give or take a couple on the last digit. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___
[time-nuts] SRS SR620 External Source Issue -- Help Request
I have an SR620 counter that I set up with a Z3801A as an external reference. If I put a bnc T connector at the output of the Z3801A and use two equal length bnc cables, one to the ext. ref input on the back and the other to channel A then do a frequency measurement, I get a mean that is about .0015 Hz below 10,000,000.Hz. Does any know why this might be happening? I would expect it to read 10,000,000. exactly give or take a couple on the last digit. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request
Your SR620 is well within its specifications, the tolerance for this test is -0.0035 Hz to + 0.0035 Hz. The readings fluctuate by that amount, but the mean is still off by -0.00150 Hz. Changing cable length... Tried it, no difference. 25Ohm load with two terms Tried all variations of with and without term. No difference. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request -- A thought
Here's a thought. Perhaps there is a problem with the rear reference input; A and B channels are fine since they read the same error. The question is Is there a way of adjusting the Reference Input so that it correctly read the 10Mhz input? I tried the same setup with my other counter and it read 10,000,000. or thereabouts correctly. So rule out the GPSDO and the cables. - Original Message - From: Dr Bruce Griffiths [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, February 21, 2007 19:47 Subject: Re: [time-nuts] SRS SR620 External Source Issue -- Help Request Hej Magnus The Frequency measurement logic (before the interpolators) appears to use a pair of 2 bit synchonisers, one for the rising edge and one for the falling edge of the internally generated frequency gate. The synchronisers synchronise the respective transitions of the frequency gate signal to the external frequency being measured. One synchroniser uses U508A + U509A the other uses U508B + U509B, so that any mismatch in propagation delays between U509A And U509B will result in a small error in the time interval. Even for ECL flipflops a propagation delay difference between U50(A and U509B of 150ps wouldn't be unusual. As far as I can tell the calibration procedures do not address this issue. The uncalibrated differential delay through the interpolation circuit source selection multiplexer will also contribute an offset. Perhaps a better assignment of propagation delay differences may be U509A and U509B 50ps, multiplexer and wiring delay mismatches 100ps. Bruce ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] SRS SR620 External Source Issue -- Help Request -- A thought
...if my model is correct the apparent offset in the mean will be increased by a factor of 10 over that for a a 1 second gate time. Bruce Looks like you're right Bruce. I did both 1, 0.1 and 0.01 gate times and the error increased by a factor of 10. And it doesn't sound like this is a fixable in any easy sort of manner, right? ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Some additional RTFG learnings
I got similar results in that the rb oscillators are not GPS disciplined after a 72 hr run. I started off by manually offsetting the frequency of a warmed up rb unit by doing a manual adjustment to the rb oscillator via the manual adjustment pot so that it would be approximately 0.0050Hz off of my GPSDO. Then I let it run for 72hrs and no change to the oscillator. A few interesting things I discovered: 1. there is the unit is putting voltage to the electronic cfield connector of the rb oscillator. I discoved this when I tried adjusting the oscillator when it was outside of the case. When I put it back in the case an entirely different frequency displayed then when I put it back in the case. When I manually adjusted the cfield pot on the rb oscillator, the unit did NOT compinsate for the manual change...which lead me to believe that there is no disciplining happening on the RB unit side. Although there might be potential for it to happen because of the voltage to the cfield pin ... perhap some sort of initialization command is needed. 2. Both the XO and the RB unit can be in operational mode simulataneously. On the Interface xover cable, I simply disconnected pins 1 and 5 (the outside pins of the top row). A simple +seems to control the A/B behavior of the XO and RB units. So both units display NO GPS off and ON lit. 3. There a little BCA shorting wires a few places on both RB and XO units. The RB unit has BC jumped at each of these locations and the XO unit has AC jumped. W201 determines from which points the unit takes the signal from to and from the oscillator. W202 and W203 determine the to and from for the GPS receivers TX and PPS signal at the interface. 4. You can xover the interface with only pins 2 and 6 on the XO to pins 4 and 9 on the RB. This simply send the GPS receiver's TX and PPS in the XO to the RB unit. By doing this both units will have 'NO GPS' off and 'ON' on. 5. Grounding the CPURESET doesn't seem to make a difference. Does anyone have an idea of what PLDENB might mean? - Original Message - From: John Ackermann N8UR [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, February 20, 2007 10:00 Subject: Re: [time-nuts] Some additional RTFG learnings I started data gathering of XO vs. XO about three minutes after yanking the interconnects as described below (but after the units had been running in GPS locked mode for well over a day). There is definitely a stabilization period required after the XO becomes operational; on this measurement, the one second tau is around 4x10e-9! I'll try to get an idea how long it takes to stabilize and report back. John John Ackermann N8UR wrote: Hi -- I'm doing some stability comparisons of the RTFG-m-RB and RTFG-m-XO units. I fired up two RTFG pairs (thanks to Jim Miller for lending me his units) with the 10 MHz and cross-over interface cables in place. The units fired up normally. I did a 24 hour frequency stability run of the RB units measured against each other, and all I learned in that time is that either (a) the RBs are not actually GPS disciplined, or (b) the loop time constant is longer than a 24 hour data collection will show. After doing the XO run, I will rerun the RBs for a longer period to see if there is any sign of discipline. Then, I disconnected the RB units so I could activate the XOs to run the same test. I thought the behaviour on doing that was worth noting: 1. Disconnect the 10 MHz reference cable. RB stays in ON mode, XO goes to FAULT. 2. Disconnect crossover interface cable. RB stays in ON mode, XO stays in FAULT and NO GPS comes on. But there is signal at the RF OUT connector. 3. In about 30 seconds, XO FAULT and NO GPS go off, ON comes on. So, the XO is definitely testing for the presence of the 10 MHz reference input signal, and becomes unhappy when it goes away. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Some additional RTFG learnings
It is not unlikely that there is a DAC for that voltage so that factory and field calibrations can be done from a remote location. I'm not sure in this case. Lucent put an awful lot of stuff in the RB unit for it to be just green light. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Some additional RTFG learnings
I traced out where most of the interface connections went to. I don't remember exactly what I found out, but I remember it was rather straight foward so I'm leaning towards it being a simple cross over. What I'm not sure about is the logic that selects the XO or the RB to be ON. But I'm not so sure that's important. What is curious is that on the daughter board, the is another jumper W202 right next to the U203 eeprom. My guess is that U203 controls the GPS stuff and the U103 has the disciplining data for the particluar oscillator. BTW you can get the RB unit to go ON with NO GPS turned off you just take an Oncore TX and PPS to the interface...no XO unit needed. - Original Message - From: John Ackermann N8UR [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, February 20, 2007 14:42 Subject: Re: [time-nuts] Some additional RTFG learnings I believe that there is more to the interface cable than a simple crossover -- I wonder if there are any pins that are jumped on one or the other of the connectors. By the way, in the experiment I reported on earlier, the XOs seem to be running undisciplined as well, and are about 1 Hz off nominal frequency. There's definitely something else needed to make these things work properly. John [EMAIL PROTECTED] said the following on 02/20/2007 02:33 PM: I got similar results in that the rb oscillators are not GPS disciplined after a 72 hr run. I started off by manually offsetting the frequency of a warmed up rb unit by doing a manual adjustment to the rb oscillator via the manual adjustment pot so that it would be approximately 0.0050Hz off of my GPSDO. Then I let it run for 72hrs and no change to the oscillator. A few interesting things I discovered: 1. there is the unit is putting voltage to the electronic cfield connector of the rb oscillator. I discoved this when I tried adjusting the oscillator when it was outside of the case. When I put it back in the case an entirely different frequency displayed then when I put it back in the case. When I manually adjusted the cfield pot on the rb oscillator, the unit did NOT compinsate for the manual change...which lead me to believe that there is no disciplining happening on the RB unit side. Although there might be potential for it to happen because of the voltage to the cfield pin ... perhap some sort of initialization command is needed. 2. Both the XO and the RB unit can be in operational mode simulataneously. On the Interface xover cable, I simply disconnected pins 1 and 5 (the outside pins of the top row). A simple +seems to control the A/B behavior of the XO and RB units. So both units display NO GPS off and ON lit. 3. There a little BCA shorting wires a few places on both RB and XO units. The RB unit has BC jumped at each of these locations and the XO unit has AC jumped. W201 determines from which points the unit takes the signal from to and from the oscillator. W202 and W203 determine the to and from for the GPS receivers TX and PPS signal at the interface. 4. You can xover the interface with only pins 2 and 6 on the XO to pins 4 and 9 on the RB. This simply send the GPS receiver's TX and PPS in the XO to the RB unit. By doing this both units will have 'NO GPS' off and 'ON' on. 5. Grounding the CPURESET doesn't seem to make a difference. Does anyone have an idea of what PLDENB might mean? - Original Message - From: John Ackermann N8UR [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, February 20, 2007 10:00 Subject: Re: [time-nuts] Some additional RTFG learnings I started data gathering of XO vs. XO about three minutes after yanking the interconnects as described below (but after the units had been running in GPS locked mode for well over a day). There is definitely a stabilization period required after the XO becomes operational; on this measurement, the one second tau is around 4x10e-9! I'll try to get an idea how long it takes to stabilize and report back. John John Ackermann N8UR wrote: Hi -- I'm doing some stability comparisons of the RTFG-m-RB and RTFG-m-XO units. I fired up two RTFG pairs (thanks to Jim Miller for lending me his units) with the 10 MHz and cross-over interface cables in place. The units fired up normally. I did a 24 hour frequency stability run of the RB units measured against each other, and all I learned in that time is that either (a) the RBs are not actually GPS disciplined, or (b) the loop time constant is longer than a 24 hour data collection will show. After doing the XO run, I will rerun the RBs for a longer period to see if there is any sign of discipline. Then, I disconnected the RB units so I could activate the XOs to run the same test. I thought the behaviour on doing that was worth noting:
Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences
I saw the vendor put up new pictures of the Thunderbolt that he has hundreds of up in his auction . The pictures aren't very clear but it looks as though HALF of the Thunderbolt is missing. There doesn't seem to be any power conditioning board. Am I wrong about this? - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED]; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 15, 2007 16:04 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences Take note that it is a very short auction-- 3 day. I would interpret this as the seller trying to do a quick test of the waters--possible nervousness. Note, no minimum bid yet. I still contend there is no market for these items at this price. Only people who don't follow this group will be the ones who rush in. Beleive me I even felt it and I have zero need for one -- just a curiousity. The same thing is happening, as I'm sure NUTS in this group have noticed, with the Symmetricom Smartsplitters on ebay. The vendor most likely has dozens if not hundreds of these, they started out selling for high prices and if it wasn't for one buyer who keeps jacking up the bids on virtually every one so far ( I think this is illegal, I'm supprised no one has reported him to ebay yet) the price would be alot lower. It's been as high as $130 and now it isn't for the one shiller, the price would be in the $20-30 range. Unless of course he is a legitimate buyer, the he can keep'em! But if ebay gets wind of it, the vendor and he will have a LONG discussion. - Original Message - From: Connie Marshall [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 15, 2007 14:27 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - PerformanceDifferenences I don't mind waiting if we can get good price. Be interesting to see if he sell any at the new $375 price. Connie K5CM -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Thursday, February 15, 2007 1:04 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences John, Once again, all due respect, I think alot time-nuts on this list would pefer to buy 2 or 3 of them for $200 or $300 than to buy one for the same price. That way we could all tinker with these things till the cows come home. A gang tinker if you like. But the only way that would happen is if everybody pulled there name from the list or made the held out for or demanded a lower price. The vendor might take one in the fist vs two in the bush (birds that is). I'm starting to sound like an anarchist... that's not my intent though. - Original Message - From: John Miles [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 15, 2007 13:28 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - PerformanceDiffereneces I think a lot of the people on the list are just looking for a good deal on a spare GPS clock. That's my situation, anyway... I'd buy one at $250, maybe a couple at $200 each just for the heck of it, but at more than $250 I wouldn't bother with any. Hopefully the seller doesn't think he has a captive/desperate market. And you're right, it would be a good idea to make sure that these units actually work before getting too excited... -- john, KE5FX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Thursday, February 15, 2007 10:18 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differeneces Actually John, I just realized the same thing happened with the RFTG units from the other vendor. (Both of my XO units did NOT work btw :-( ) The vendor was tipped off... ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences
**That's a big problem if there is no power conditioning board. ** The DC-DC converter is very expensive itself and there is A LOT of filtering before it AND that's all after a DC input!!! I saw somebody suggested a cheap switching power supply as a power source, but that will not be sufficient. There is a reason for an expensive DC-DC converter and all that filtering... Garbage in, Garbage out. The precision of the circuitry, antenna, 10Mhz and cpu all require a very clean and stable power source for good performance. Anyone who knows switching power supplies will know that they are sensitive and noisy. They are cheap and small but not good enough to feed directly into the processor board. The DC-DC stabilizes the input signal, switching power supplies, especially the cheap ones, are extremely sensitive the power anomalies on the input side and load variation on the output side (like the OCXO oven turning on and off). Take a look at the Z3801A's power conditioning board, that's after the dc input! Take look at all the conditioning that the other Thunderbolt board on ebay has on it (which is more than a regular Thunderbolt too). There is a reason for that...clean and stable power to all the components. That's why the industrial versions of the Thunderbolts like the Z3801A clone have more filtering and higher quality parts then your standard Thunderbolt. .the cleaner the power, the better the performance i.e. Garbage in, garbage out. I just feel sorry for that person who has already bid on the one for $250. After realizing the whole power conditioning board is gone, the price I'm willing to pay has gone down to $50-$75 even with the splitter and pretty cables. - Original Message - From: Didier Juges [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, February 17, 2007 11:51 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences [EMAIL PROTECTED] wrote: I saw the vendor put up new pictures of the Thunderbolt that he has hundreds of up in his auction . The pictures aren't very clear but it looks as though HALF of the Thunderbolt is missing. There doesn't seem to be any power conditioning board. Am I wrong about this? I believe you are correct. Someone stated there was no DC/DC converter board, so you need to provide +5 and +/-12. The Thunderbolt data sheet is very confusing about power consumption. It states the unit needs about 10W, but lists the current draw as 300mA on the +5V and 25mA on the +/-12V. Where is the oven power coming from? My Thunderbolt with DC/DC converter draws about 400mA from +24V, so the 10W stabilized sounds about right. I wish the pictures were clearer, and that there were a picture of the front of the unit. It's hard to believe the seller has 100's of those units which he tries to sell for $250 or more, and can't even afford to make a couple of decent pictures of what he sells. I am not sure what is the device that looks like a coupler on the bottom, but it seems like you get a couple of cables with it. Didier KO4BB ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Thunderbolt - Shipping Outside the USA
have to pay (though I think anyone here would be willing to list a low value as a gift to help minimize those costs). The problem is that if your sending that many at once, customs will get suspicious about the cost AND do you really want to send that many without being properly insured . If you send one at a time, I imagine that's a lot of paperwork that somebody is going to spend a lot of time filling out. Best to keep it on the up and up. Hopefully the price of the item will be low enough that it will offset the price of proper shipping. Another reason for holding out for a lower price. - Original Message - From: Jason Rabel [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Friday, February 16, 2007 12:24 Subject: Re: [time-nuts] Thunderbolt - Shipping Outside the USA Peter (and others), I talked to my guy about shipping UPS internationally. The UPS Expedited service (cheapest they offer) is one to three days but the rates are obscene! You can figure about 25% off the book rate for the discount he gets, but you still have to add in the fuel surcharge and such. However, USPS rates are a LOT cheaper (1/2 to 1/4) for the airmail parcel, it just takes a little longer (I don't think anyone would want surface parcel). So I think USPS would be the way to go. And don't forget about any tax / duties / customs fees that you guys would have to pay (though I think anyone here would be willing to list a low value as a gift to help minimize those costs). Jason Yes, I agree - particularly when considering the cost and difficulty of shipping out of the USA. At that price, though, I would certainly consider two units to play with, but over $200 each seems unreasonable. Peter ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] Thunderbolt - Hardware Versions - Performance Differneces
There are different hardware variations of the Thunderbolt out there. There is the commercially available Thunderbolt which available from Trimble that everyone is familiar with, and then there are the industrial versions that are made for the telecoms. The Andrews E-911 version, unfortunately, looks to be regular commercial version from what I can see from the board layout and the form factor. I'm lucky enough to own a couple of Thunderbolts as well as some of the different telecom versions and they DO NOT have the same performance. The commercially available Thunderbolt (the one comes in the little red box) has the least favorable performance when compared to the industrial versions. I've found that the industrial Thunderbolts, with their better hardware and much nicer oscillators, have a stability that is comparable to the Z3801A (if not exceeding it). My commercial Thunderbolts have more jitter and don't stabilize as quickly as the higher end boards. I don't have a cesium or hm to give hard Allan Variance numbers but I do use a counter that in it's nulling mode will show differences as small as 1.9e-9Hz ( 0.19 Hz ). Using a 10sec gate I'll watch how often the lower differences are displayed. So if I see a number displayed 1.0e-3Hz show up a lot, I'll know that the oscillator has more jitter than an oscillator that consistently displays 1.0e-3Hz. But when I have an oscillator that is very stable I will see a lot of differences in the 1e-6Hz and 1e-9Hz range. I notice that commercial Thunderbolts display readings that have greater variance than the industrial boards when referenced against one of my favorite HP Z3801A's. The industrial boards have a much tighter variance will show a lot of differences in the 1e-6Hz and 1e-9Hz range much more often. Hardware wise: The industrial versions seem to have better power supplies with more filtering (since they are not limited by space I guess). They also have to seem more components that support the cpu (possibly for added functionallity or to support different algorithms). And of course, the oscillators. The single oven in the commercial Thunderbolt does seem to even come close to the industrial boards. The industrial boards I have are the Z3801A clone with a double oven oscillator and a couple of boards with high-end Vectrons. On Trimble's Thunderbolt web page, there is a link for a Thunderbolt Performance with a Double Oven Oscillator. I think people might be mislead to believe that is the performance of the commercial Thunderbolt that they are selling, but it's not. What the are showing is the performance of what I believe to be one of the industrial boards with an older high-end Vectron double-oven (the model 330Y4472) which was available in the Z3801A clone made for Nortel. The commercial version doesn't even come close to that. I think the holy grail of Thunderbolt boards is the Nortel boards. The are still in service and have their firmware updated by Trimble unlike (the commercial version which Trimble doesn't give any info about firmware upgrading).Unfortunately, the Thunderbolt everyone want to buy from this seller who has hundreds of them, is (and I say this with 99.94% certainty) a regular, commercial Thunderbolt in a different housing. I certainly won't pay $250 for one. And if this guy has 'hundreds', he will discover there is no market for them at $250. I'll pick one up when it dips below $100. The other Thunderbolt board on ebay now, with the 5 10mhz outputs is a steal at $225 if you can get one of the last four. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Thunderbolt - Hardware Versions Performance Differences
John Miles wrote: People with Z3801As tend to fiddle with them until the cows come home in my experience, and that's fine if that's what you're into, but... wait, what list is this again? :) I put my info and experience with Thunderbolts out there for the NUTS in this mail list. I have a few and I see people are looking for the info. I'd hate to see people spend $250 on something they might think is as good as a Z3801A (or its Trimble clone) or might misread the Thunderbolt webpage and think they are getting a Double-Oven AND in a few months will cost less than $100 ( I say this only because there is no market out there for a few of hundred, used $250...actually now I see $375?!?!? mediocre 10Mhz GSPDO's. ( and I say mediocre from the NUTS perspective ;-} ) Anybody who is the least serious about 10Mhz is going to run across the mail list in a Google search. If the list group by gets to 100 people, that still leaves a couple hundred left over. I doubt that the price is going to stay above $100 let alone $200 after the initial rush, it doesn't make sense. Supply and demand. The market has now been flooded, demand will recede after the initial ooh look!! crowd rushes in, the price point will drop. My opinion of course (and Alfred Marshall's). Anyway, you're right. The commercially available Thunderbolt is good enough for a plug-n-play 10Mhz source, but if you want to be a NUT about it, get one of the industrial boards like the Nortel version if you can find it. Like I said, I'll wait till the price drops to under $100 bucks, that way I could, without fear, fiddle with it till the cows come home. - Original Message - From: John Miles [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 15, 2007 11:58 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions -PerformanceDifferneces I guess it depends on whether you are after a frequency reference or a phase reference. My (commercial) Thunderbolt has no problem delivering 1E-10 or better over 1 second (usually MUCH better). Jitter has never been a problem for me, and I couldn't care less about holdover performance, since I don't run my own cell site. If all you want is a reliable, plug-and-play source of 10 MHz, there are literally no drawbacks to these boxes. They just work, and $200-$250 is a fair price for them. People with Z3801As tend to fiddle with them until the cows come home in my experience, and that's fine if that's what you're into, but... wait, what list is this again? :) -- john, KE5FX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Thursday, February 15, 2007 7:35 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Thunderbolt - Hardware Versions - PerformanceDifferneces I'm lucky enough to own a couple of Thunderbolts as well as some of the different telecom versions and they DO NOT have the same performance. The commercially available Thunderbolt (the one comes in the little red box) has the least favorable performance when compared to the industrial versions. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences
Take note that it is a very short auction-- 3 day. I would interpret this as the seller trying to do a quick test of the waters--possible nervousness. Note, no minimum bid yet. I still contend there is no market for these items at this price. Only people who don't follow this group will be the ones who rush in. Beleive me I even felt it and I have zero need for one -- just a curiousity. The same thing is happening, as I'm sure NUTS in this group have noticed, with the Symmetricom Smartsplitters on ebay. The vendor most likely has dozens if not hundreds of these, they started out selling for high prices and if it wasn't for one buyer who keeps jacking up the bids on virtually every one so far ( I think this is illegal, I'm supprised no one has reported him to ebay yet) the price would be alot lower. It's been as high as $130 and now it isn't for the one shiller, the price would be in the $20-30 range. Unless of course he is a legitimate buyer, the he can keep'em! But if ebay gets wind of it, the vendor and he will have a LONG discussion. - Original Message - From: Connie Marshall [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 15, 2007 14:27 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - PerformanceDifferenences I don't mind waiting if we can get good price. Be interesting to see if he sell any at the new $375 price. Connie K5CM -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Thursday, February 15, 2007 1:04 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differenences John, Once again, all due respect, I think alot time-nuts on this list would pefer to buy 2 or 3 of them for $200 or $300 than to buy one for the same price. That way we could all tinker with these things till the cows come home. A gang tinker if you like. But the only way that would happen is if everybody pulled there name from the list or made the held out for or demanded a lower price. The vendor might take one in the fist vs two in the bush (birds that is). I'm starting to sound like an anarchist... that's not my intent though. - Original Message - From: John Miles [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 15, 2007 13:28 Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - PerformanceDiffereneces I think a lot of the people on the list are just looking for a good deal on a spare GPS clock. That's my situation, anyway... I'd buy one at $250, maybe a couple at $200 each just for the heck of it, but at more than $250 I wouldn't bother with any. Hopefully the seller doesn't think he has a captive/desperate market. And you're right, it would be a good idea to make sure that these units actually work before getting too excited... -- john, KE5FX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED] Sent: Thursday, February 15, 2007 10:18 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt - Hardware Versions - Performance Differeneces Actually John, I just realized the same thing happened with the RFTG units from the other vendor. (Both of my XO units did NOT work btw :-( ) The vendor was tipped off... ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] TRIMBLE GPS RECEIVER MODULE PART# B12118-13321
Someone just posted Thunderbolt type boards for $275 on ebay. Claims might have a better oscillator then stock Thunderbolt and 5 10mhz outs + power supply. Still a good deal. Only three though. - Original Message - From: Robert Deliën [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, February 13, 2007 14:50 Subject: Re: [time-nuts] TRIMBLE GPS RECEIVER MODULE PART# B12118-13321 I doubt he even paid $100 each for them. If he has a few hundred of them he probably got them on a pallet bundle in an auction or about to be junked. Exactly; If he has over 100 units it's highly unlikely he paid $100 a piece for them. Very few people would pay that kind of money for so many units. If you do, you know would know exatcly what they are, you would have a destination for them and you would be on this mailing list ;-) He might be able to sell a few at a premium price on eBay, but after that Yes, there are a number of people who are willing to $250 for them, but that number is very limited. I've seen it many times before: After selling a few at premium prices, the price rapidly drops. Remember, the highest bidder of the bunch 'wins' the auction, the bunch is more or less constant, so the next item is usually going for less than the one before. As for eBay fees... my calculations show about $16 - $20 for insertion + ending fees. PayPal takes approx another 3% of what is sent, so that's at least another $8. Assuming the price stays at $250... Any higher and of course they go up. Make him an offer of $200 @10 pieces and don't forget to remind him he's already making a huge profit on that and that it saves him a lot of hassle. For that price you can count me in too ;-) For $300 I'd probably save my money for a PRS10 diciplined by a Resolution-T. (Would that be a good idea, anyone?) Robert. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Lucent RFTG-m-XO
I had the exact same problem as yours. I discoverd that my 106B had a 6-channel board in it vs. the 8-channel that is supposed to be in there. I put a 8-channel board in and the fault and GPS lights went out. - Original Message - From: Robert E. Martinson [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Tuesday, February 06, 2007 11:27 Subject: Re: [time-nuts] Lucent RFTG-m-XO Over the weekend I left the XO unit running for 38 hours, with it installed in its house (No probing). The GPS receiver was tracking satellites at the start and also at the end of the run as verified by monitoring J5-2 w/VisualGPS. The Fault No GPS LEDs never went out. I'm about to conclude that I have a defective unit and will order another unless anyone has any further suggestions (PLEASE)? I see at least John A., Jim M., Phil S. have working XO units. I have just reviewed all the emails on the RFTG units and believe I have tried all the previous suggestions. Any additional secrets to share??? Bob Martinson, N1VQR -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Phil Staton Sent: Thursday, February 01, 2007 6:53 PM To: time-nuts@febo.com Subject: [time-nuts] Lucent RFTG-m-XO Briefly: Leave it running for at least 24hrs. The 15MHz will slowly get on freq. Countup is available on 1pps socket. more when I have time ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] RFTG on ebay
Fair enough. I just thought they're pricing strategy kind of funny (and I don't mean funny-ha-ha). It seems the price suddenly went up $100 as soon as some posts some progress on time-nuts. If you don't want me to continue this thread, I won't. It just seems they're taken advantage of your group in a way that is unfair to the group members. Thanks Flav - Original Message - From: John Ackermann N8UR [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, February 01, 2007 13:49 Subject: Re: [time-nuts] RFTG on ebay The Infamous Flavio wrote: Is it me or is kinda wierd that a vendor is posting on this list? I've been following the RFTG discussions with great interest, and wanted to buy a some boxes from that vendor on ebay but they posted a messagein this group saying the have two RB boxes left, then I look at their store this morning and they posted a bunch at REALLY high prices?!?!? I don't know but looks like that vendor is monitoring this group and jacking up the prices based on everybody's progress regarding the RFTG units. I don't want to rabble-rouse on my first post but I thought it kinda weird. From the administrator: The list is open to anyone with an interest in time and frequency topics. We have lots of folks who work in the industry, and they are all welcome. We do ask that people avoid anything beyond very occasional commercial activity on the list. i.e., one posting about a product known to be of interest to the group is OK; regular postings would be a problem. I don't have a problem with the single message that was posted yesterday; if it was repeated, I'd be somewhat concerned. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] RFTG on ebay
I saw the $20 thing, more weirdness. Anyway, that's wasn't my point. That post said that they have only two RB units left, but eleven are up on ebay?!?! - Original Message - From: Jason Rabel [EMAIL PROTECTED] To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Thursday, February 01, 2007 14:28 Subject: Re: [time-nuts] RFTG on ebay I think their prices were more of supply demand... The first lot of RFG-RB's that they sold had a BIN for $20!!! (I missed out on those or I would of bought them all), the next lot I believe had a $50 BIN (again, missed out on those too), then $125, then $185, etc... Each new lot they listed just kept going up as people were continuing to buy them all. The RFTG's were not listed until after the RFGs were already being sold for the $125/$185 area. I don't know what the MSRP would be on one of these, probably so high it would make me have a mild stroke. But for $125 that I bought my RB for, even just the LPRO-101 is worth that price. At $185 I probably would have passed on the deal. I'm waiting for the XO model to drop down to about $125, if they do then great, if they don't then I'll just have to be patient and wait for some other surplus units to hit eBay at a price I'm willing to pay. Anyhow, that post with their quantities left I found kind of informative. It let me know how many units they have left (a bunch) of the model I want. So I know I can still wait a while and hope for the price to fall some more. I'm not trying to defend that vendor, but I bet you didn't know about their initial listings that were way below value (and some people got in on killer deals). Jason Fair enough. I just thought they're pricing strategy kind of funny (and I don't mean funny-ha-ha). It seems the price suddenly went up $100 as soon as some posts some progress on time-nuts. If you don't want me to continue this thread, I won't. It just seems they're taken advantage of your group in a way that is unfair to the group members. Thanks Flav ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
