[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...

[Tom Miller]

I am surprised the schematics for these have not surfaced yet. Are they not 
out of support now?
I got a set and am awaiting on a power supply and some connectors. Anyone 
have a source for the latches for the D connectors?

Tom



----- Original Message ----- 
From: "Anthony Roby" <aroby at antamy.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday, October 23, 2014 10:39 PM
Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, 
Z3811A, Z3812...


> My curiosity got the better of me so I ordered these earlier this week and 
> received them today.
>
> I've powered both up and quickly measured the 10MHz output.  I don't yet 
> have a GPS antenna feed that I can connect, so couldn't check that out. 
> And I need to look into why both of the units have the Fault and StdBy 
> lights illuminated.  I was surprised how compact they are and they weight 
> next to nothing.  And they are very nicely made.  I took the tops off both 
> and took some photos (see http://goo.gl/87e8GG), but have not ventured 
> into unscrewing everything to get to the bottom of the boards.  From the 
> top, I didn't immediately spot anything extra on the board for the 10MHz 
> out.  All the extras appear to be for the GPS, but the underside of the 
> boards may tell a different story.
>
> Anthony
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Bob 
> Stewart
> Sent: Thursday, October 23, 2014 12:20 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, 
> Z3811A, Z3812...
>
> My units came in today. What I got appears to be new-in-box. It's probably 
> the only thing I'll ever get with a blue Agilent sticker on the box. =) It 
> has a yellow Symmetricom notice inside the box.
> The circuit board appears to be the same on both units, but that says 
> nothing about the firmware, of course. The REF-1 has an Oncore receiver 
> labeled TM-AB - whichever one that is, small parts to support it, and a 
> TNC connector for the GPS receiver.
>
> The REF-0 is missing everything related to the receiver, and has an SMA 
> for the 10MHz output in the space where the REF-1 has the TNC along with a 
> few extra small parts. This is a shared space with both SMA and TNC pads, 
> though they don't seem to share the same electrical path. Since the SMA 
> and TNC share the same physical space, even if the 10MHz is available 
> somewhere, you'd have to do some surgery on the case before you could 
> bring it out. Probably by adding a hole in the case for the GPS antenna 
> and using the pad space for the SMA.
>
> It will be a day or two before I have the bits to apply power and connect 
> an antenna. So, that's what I know. I'd probably just break something if I 
> tried to find and bring out the 10MHz, so I'll have to leave that to 
> someone else. But, the appropriate signals need to get between the boards, 
> so I wonder what's on the Interface pins? Maybe just arbitration, 1PPS, 
> and sawtooth comms?
> In my case, I do need the 10MHz, so I'm just as happy to have bought both 
> units at this point. Maybe, down the road, someone will come up with the 
> mods to convert a REF-1 into a REF-0, and vice versa, unless the firmware 
> prevents that.
>
> Bob
>     From: GandalfG8--- via time-nuts <time-nuts at febo.com>
> To: time-nuts at febo.com
> Sent: Tuesday, October 21, 2014 5:59 AM
> Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, 
> Z3811A, Z3812...
>
> It seems from the auction revision table that this seller has been 
> offering  these for some time, so perhaps another "hidden" gem:-), but 
> it's perhaps also worth noting that if this system functions on similar 
> principles to earlier RFTG kit then the GPS conditioning is only applied 
> to the unit actually containing the GPS module, with the other unit 
> intended as a standby should the first one fail.
>
> In other words, unless the system redundancy is really required most users 
> would probably only need the GPS based unit, or would at least be better 
> off buying two of those for the same money that the "matched" pair would 
> cost.
>
> The only advantage, as far as I'm aware anyway, of the non-GPS unit is 
> that  it contains a 10MHz output.
> However, Skip Withrow published modification details in January 2013 
> showing how straightforward it was to add the the 10MHz output, to the 
> RFTGm-II-XO module, the PCB location for the socket was already available, 
> so I would suspect it wouldn't be too difficult on these either.
>
> Regards
>
> Nigel
> GM8PZR
>
>
> In a message dated 20/10/2014 05:53:29 GMT Daylight Time, 
> stewart.cobb at gmail.com writes:
>
> 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
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