[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812A GPSDO system

Tom Miller tmiller11147 at verizon.net
Tue Oct 28 23:41:42 EDT 2014


Until you have the two units tied together and GPS ok and the Fault light 
out, you won't see the 15 MHz signal. You should see a 5 volt pp square wave 
of sorts coming out of the 10 MHz port.

I found a clean 10 MHz signal on the collector of Q208 and several other 
points. These are on the back side of the board, near the 15 MHz connector.

I am trying to find out how they triple the 5 MHz to get 15 MHz. Maybe it 
can be changed to just double to 10 MHz. There are a few inductors on the 
board and that may make for a filter.

I don't yet have a computer connected. Does the SatStat program run under 
windows?


Regards,
Tom



----- Original Message ----- 
From: "Anthony Roby" <aroby at antamy.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, October 28, 2014 10:52 PM
Subject: Re: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, 
Z3811A, Z3812A GPSDO system


>I played around today with these interfaces and couldn't get anything out 
>of them.  I still don't have my GPS connected, but I would have thought I'd 
>see something out of one of the ports.   I tested the serial port on my PC 
>and that is working, but I don't see anything of note coming off the RFTGs. 
>I have not connected both together through J5 - maybe that's the next thing 
>to try.  Any particular reason why the -ve side of the RS422 signal is used 
>vs. the +ve?
>
> I was able also to get SatStat and the RFTG software running on Windows XP 
> under VirtualBox.  Hopefully once I get a signal out of the units, that 
> software will be stable.
>
> Anthony
>
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Stewart 
> Cobb
> Sent: Sunday, October 19, 2014 11:53 PM
> To: time-nuts at febo.com
> Subject: [time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, 
> Z3811A, Z3812A GPSDO system
>
> 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.
>
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