TrueTime Symmetricom XL-DC GPS OCXO 10Mhz GPSDO Oscillator LCD Clock ** READ** [Used]

*** MILITARY SPEC. VERSION - READ BELOW *** • Upgraded OCXO Oscillator • Large Left Backlit LCD Time Display • 5V Antenna Power • GPS Disciplined 10MHz Oscillator • Atomic Clock Timecode Receiver • 10Mhz 5Mhz 1MHz Frequency Outputs • IRIG-B / 1PPS • 115V or 230V Power

Actual item for sale

Description

Here's a lightly used TrueTime/Symmetricom XL-DC GPS time receiver/timecode generator in good cosmetic condition. It is equipped with an upgraded OCXO oscillator. It has been tested for acquisition of GPS Time Sync and for good GPS Time, Date, Timecode and Frequency outputs.

I believe that this may be a military variant of the XL-DC clock/Frequency Generator/Timecode Source. The main differences are:

1. Normally the XL-DC defaults to UTC time and can be set to GPS time as an option. This unit seems to have been ordered with the time locked to GPS time and I could not find a way of changing that (Function 01 is garbled on the display and Function 69 is missing). GPS time is 18 seconds ahead of UTC. The fact that the unit displays GPS time does not affect the accuracy of the disciplined 1PPS,10, 5 and 1 MHz outputs.
   
   
2. I was unable to send and receive data using the DB9 RS-232 serial port using my test PC's Hyperterminal application. That may indicate that the device has been optioned with the RS-422 serial protocol or that hardware flow control is needed, so my PC's 3-wire serial card can't communicate, but I have not explored this further. It may indicate that this capability was not provisioned at the request of the original purchaser. In any case, all the important parameters for the device are accessible via the front panel keypad, so the serial I/O is probably unnecessary for most applications. Please proceed on the basis that the serial I/O port is inoperative.
   
   
3. The unit has a couple of expansion cards installed (86-729-15 and 86-383-5) which I presume are for a military application. I have not explored their features for lack of available documentation, but I do see some config options coming up on the front panel so I assume they are working as they should, but this is not guaranteed.

The internal Lithium memory back-up battery has just been replaced so that should not need further attention for some years. Both LCD displays have a backlight; both are bright and even - see photos which show the actual item for sale.

A basic test antenna is included to get you started - so you may need to take both receiver and antenna into the open air to test the device. The Antenna voltage is 5V so almost any good quality GPS antenna should work, but try and have at least 26dB of antenna gain if you want to replicate my test results. A Symmetricom AT575 type is recommended and I usually have some listed separately. Rack ears are included as shown. No printed manual is included but a copy may be downloaded from https://www.prostudioconnection.net/1112/xl-dc-manual.pdf. No unpictured cables, accessories or documents are included.

So if you're looking for a very affordable GPSDO with a cool display and the time offset isn't a concern then this may be a very attractive purchase. Alternatively if you have a spare XL-DC CPU module and want to try a swap then it would seem that the OCXO module, chassis, power supply and display boards are all good. Note that there's a little corrosion at the right end of the rear panel. This appears to have been caused by coming into contact with something outside the case and not a leak inside the case - see photo.

Actual item for sale

Features

• Less Than 40 Nanoseconds rms Accuracy to UTC
• Better Than 1x10-12 Frequency Accuracy
• Versatile and Modular Architecture
• Supports Many Different Output Options
• 10Mhz, 5Mhz and 1MHz Sine Wave Outputs
• 1 PPS Output
• IRIG B Time Code Output