HI There are a few possible variations:
1) Different power supply voltages 2) Cheating RS-232 versus a proper RS-422 converter 3) The “right” interface cable (what ever it’s pinout is) versus a VGA cable ( or no cable at all…) 4) The HP interface versus the Lucent one 5) Windows 3.11 versus Windows 10 beta (or maybe something in-between). I’m only observing that some have had more luck with these than others. Since they are all NOS, they should all work. That suggests one or another hookup issue. I don’t think there is any need for ultra long detail lists. Stu took care a lot of that. I don’t have one, so at this point I’m just an observer on the sidelines. Bob > On Oct 29, 2014, at 7:33 PM, Tom Miller <[email protected]> wrote: > > Hi Bob, > > Most of the answers were covered with Stu Cobb's original message from > 10/20/14 copied below. > > > > > ----- Original Message ----- From: "Bob Camp" <[email protected]> > To: "Discussion of precise time and frequency measurement" > <[email protected]> > Sent: Wednesday, October 29, 2014 6:55 PM > Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, > Z3810A,Z3811A, Z3812A GPSDO system > > >> Hi >> >> One thing that might help others who are having issues with these units: >> >> Which pins did power go to? >> >> Which pins do you see RX (and maybe TX) data on? >> >> Which cables went where (and their pinout) to interconnect this or that? >> >> What software are you using? >> >> Yes, One could make some pretty quick guesses at most of this. It’s often a >> quick guess gone wrong that messes people up … >> >> Bob >> > ____________________________________ > > Fellow time-nuts, > > This (long) post is a review of the HP/Symmetricom Z3810A (or Z3810AS) > GPSDO system built for Lucent circa 2000. I wrote it because I looked > for more information before I bought one, and couldn't find much. > It's relevant because (as of this writing), you can buy a full system > on the usual auction site for about $150 plus shipping. For those of > you lamenting the dearth of cheap Thunderbolts, this looks like one of > the best deals going. The description of these objects does not > include "GPSDO", so time-nuts may have missed it. Search for one of > the part numbers in the subject line and you should find it. > > So what is it? It's a dual GPSDO built by HP as a reference > (Redundant Frequency and Time Generator, or RFTG) for a Lucent > cell-phone base station, built to Lucent's spec KS-24361. Internally, > it's a close cousin of a later-model Z3805A. Externally, it looks to > be almost a drop-in replacement for the earlier RFTG system built to > Lucent's spec KS-24019. That was a redundant system containing one > rubidium (LPRO, in the one I have) and one OCXO in two > almost-identical boxes. That spec went through several revisions with > slightly different nameplates and presumably slightly different > internals. You can generally find one or two examples on the auction > site (search for RFTG or KS-24019). > > This system is similar, but the two boxes each contain a Milliren > (MTI) 260-0624-C 5.000MHz DOCXO, and neither contains a rubidium. The > Milliren DOXCO is the same one used in the later models of the HP > Z3805A / 58503A. It's a very high-performance DOCXO, in the same > class as the legendary HP 10811, and better than the one in most > surplus Thunderbolts. The 5 MHz output is multiplied up to 10 MHz in > at least one unit, and 15 MHz in both units. I don't have the ability > to measure phase noise on these outputs, but I'd be interested to see > the results if someone could. > > Nomenclature: The Z3810AS (there always seems to be an "S" at the > end) is a system consisting of the Z3811A (the unit containing a GPS > receiver), the Z3812A (the unit with no GPS receiver), and the Z3809A > (a stupid little interconnect cable). The GPS receiver inside the > Z3811A is a Motorola device, presumably some version of an OnCore. > Where the Z3811A has a TNC GPS antenna input, the Z3812A has an SMA > connector labeled "10MHz TP". That is indeed a 10 MHz output. It > comes active as soon as power is applied to the unit, and its > frequency follows the warmup curve of the OCXO. The two units have > identical PCBs (stuffed slightly differently), and I have no doubt > that someone can figure out how to add a 10 MHz output to the Z3811A > as well. > > Operation: From the outside, these units are broadly similar to > earlier units in the Lucent RFTG series. The (extremely valuable) > website run by Didier, KO4BB, has a lot of information on those > earlier units, much of which still applies here. The purpose of these > units was to provide a reliable source of frequency and timing > information to the cell-site electronics. The 15 MHz outputs from > both units were connected to a power combiner/splitter and directed to > various parts of the transmitter. The units negotiate with each other > so that only one 15 MHz output is active at a time. The outputs > labeled "RS422/1PPS" contained a 4800 baud (?) serial time code as > well as the PPS signal, which were sent to the control computer. > > Power is applied to the connector labeled "+24VDC" and "P1", in > exactly the same way as the earlier RFTG units. Apply +24V to pin 1 > and the other side of the power supply (GND or RTN) to pin 2. In > these units, that power supply goes directly to an isolated Lucent > DC/DC converter brick labeled "IN: DC 18-36, 1.9A". Presumably you > can run both units with a 4-amp supply. > > Once you have applied power, connect the Z3809A cable between the > jacks labeled "INTERFACE J5" on each unit. The earlier RFTG units > used a special cable between two DE-9 connectors, and it mattered > which end of the cable connected to which unit. The interconnect for > these units is a high-density DE-15 connector (like a VGA plug). The > Z3809A cable is so short that the two units need to be stacked one > above the other, or the cable won't reach. It doesn't seem to matter > which end of the cable goes to which unit. I don't know whether it's > a straight-through cable, or whether you could use a VGA cable as a > substitute. > > When you apply power, all the LEDs on the front panel will flash. The > "NO GPS" light will continue flashing until you connect a GPS antenna. > Once it sees a satellite, the light will stop flashing and remain on. > The unit will conduct a self-survey for several hours. Eventually, if > all is well, the Z3812A ("REF 0" on its front panel) will show one > green "ON" light and the Z3811A ("REF 1") will show one yellow "STBY" > light. This means that the Z3812A is actually transmitting its 15MHz > output, and the other one is silently waiting to take over if it > fails. > > Most time-nuts want to see more than a pretty green light. The old > RFTG series allowed you to hook up a PC to the "RS422/PPS" port and > peek under the hood with a diagnostic program. The program is > available on the KO4BB website. It is written for an old version of > Windows, and I had no luck getting it to run under Windows 7. It does > run under WINE (the Windows emulator for Linux) on Ubuntu 12.04 LTS. > To use it, you need to make an adapter cable to connect the oddball > RS-422 pinout to a conventional PC RS-232 pinout. The adapter cable > looks like this: > > RFTG PC > > DE-9P DE-9S > > 7 <----------> 5 > > 8 <----------> 3 > > 9 <----------> 2 > > (According to the official specs, this is cheating, because you're > connecting the negative side of the differential RS-422 signals to the > RS-232, and ignoring the positive side of the differential signals. > However, it's a standard hack, and it's worked every time I've tried > it.) > > With that adapter, you can see the periodic timetag reports from the > unit. The RFTG program will interpret these timetags when it starts > up in "normal mode". However, when I try to use any of the diagnostic > features built into the program, it crashes WINE. The timetag output > was required for compatibility, but I suspect that HP didn't bother to > implement the Lucent diagnostics. > > Instead, they added a connector which is not on the previous RFTG > series. That connector is labeled, logically enough, "J8-DIAGNOSTIC". > It too is wired with RS-422, so you need to use the same adapter cable > as before. Once you do, you'll find that this connector speaks the > usual HP SCPI command set (Hooray!). I used the official SATSTAT > program (again under WINE on 12.04 LTS), but I'm sure that other > programs written for this command set will work as well. The default > SATSTAT serial port settings of 9600-8-N-1 worked for me. > > After about 24 hours, with a poorly-sited indoor GPS antenna, my > system has converged to TFOM=3, FFOM=0 (the best possible numbers), > and a "predicted 24-hour holdover uncertainty" of 5.2 microseconds, > which is not too shabby. It found the correct day and year without > any assistance, so if it has a "GPS week number rollover" problem, > it's still in the future. I don't currently have the ability to > compare the 10 MHz output to anything else. Again, if someone else > can, I'd be interested to see the results. > > Additional Notes: The parts on the boards all have date codes of 1998 > or 1999. The Motorola GPS receiver has a firmware label that reads > "02/04/00". The SCPI error logs inside the HP units were virgin when > I first got them. They had 84 and 94 power cycles, respectively. > Before the GPS receiver acquired time, the error log timestamps read > "2000-05-09 00:00:00", which I interpret as a firmware release date. > > The PCB has an interesting feature. Next to each soldered-in pin of > the Milliren OCXO is a single-pin socket soldered into the board. I'm > guessing this was used in manufacturing, to temporarily install a > Milliren and confirm that the system worked before permanently > soldering it in. (At production prices, the Milliren would have cost > far more than the rest of the PCB.) You might be able to use this in > reverse, if you have a set of Millirens to test from another source. > > The Z3809A interconnect cable has three of the 15 pins on each end > clipped a bit shorter than the rest. Not so short that they won't > eventually make contact, but short enough to make contact later than > the rest. Don't know why, but it's clearly deliberate. A lot of > hot-plug connectors are built that way, including USB connectors. I > have no idea what the pinout of the interconnect is. > > The redundant system slaves both DOCXOs to the same GPS reference. > Inside the GPS loop bandwidth, the two oscillators will have almost > the same frequency and will differ only by phase noise and short-term > stability. This is almost a perfect setup for experimenting with > certain kinds of time-nut measurements, assuming someone can figure > out how to get 10MHz out of the Z3811A unit. If you then command both > units into holdover, you could measure longer-term stability as well. > > The units are described as "new in factory sealed box". After an > archeological investigation of the various strata of labels and tape > on the boxes, I would say that's probably accurate. My set seems to > have been shipped from the Agilent factory in Korea to Symmetricom in > Sunnyvale, CA sometime in August, 2000, shortly after it was built, > and remained untouched until I opened it. I'm guessing it was built > and saved as part of a spares program for Lucent, and kept until > Lucent decided they didn't need spares any more. > > I have no connection with the current seller of these units (or any > other sellers, for that matter) except as a satisfied customer. I > think I'll order another set as a spare, before the feeding frenzy > hits. > > Request for help: Both the SatStat and RFTG programs run under WINE > on stock Ubuntu 12.04 LTS (32-bit) without any tricks or special > configuration. Neither seems to run under WINE on Ubuntu 14.04 LTS > (64-bit). I am a WINE novice. Any hints from WINE experts would be > appreciated. Also, I've been able to run TimeLab under WINE, but I > can't connect it to my USB-to-488 interface, so I can't take data. If > anyone can tell me how to set that up, I'd be extremely grateful. > > Cheers! > --Stu > _______________________________________________ > > _______________________________________________ > 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.
