MG-73A [10 MHZ REFERENCE & DIS - MERCURY UNITED ELECTRONICS

Mercury United Electronics, Inc.

10823 Edison Court

Rancho Cucamonga, California 91730 U.S.A.

TEL: (909) 466-0427, 1-888-310-8382

Fax: (909) 466-0762

e-mail: sales-us@mercury-crystal.com

www.mercury-crystal.com

GPS FREQUENCY REFERENCE

RECEIVER AND DISTRIBUTOR

MODEL: MG73-A

USE’R GUIDE

Version 1.1, October 2004

CERTIFICATION

Mercury United certifies that this instrument was thoroughly tested and inspected and

found to meet its published specifications when it was shipped from the factory.

WARRANTY AND ASSISTANCE

Products manufactured by Mercury United are warranted against defects in material and

workmanship. This warranty applies for one year from the date of shipment. OEM products

used in Mercury United systems are warranted as indicated by the respective

manufacturer. During the warranty period, Mercury United will, at its option, either repair

or replace products that prove to be defective. The repaired or replaced product will be

warranted for a period of 90 days from the date of return equipment, or for the balance of

the original warranty, whichever is longer.

To obtain repair under this warranty, the buyer must obtain a RMA (Return Authorization)

number from Mercury United and return the equipment to a designated repair location.

In the USA, all warranted shipments by UPS ground track will be paid by Mercury United.

All other shipping methods will be billed to the customer. In the case of equipment

returned from a country other than the United States of America, the buyer shall pay all

applicable duties or taxes required and freight charges both ways.

No other warranty is expressed or implied. In no event will Mercury United or any person

involved in the creation, production, or distribution of the Mercury United products be

liable for any direct, indirect, special, incidental, or consequential damages resulting from

the buyer’s use of this equipment or software supplied by Mercury United. It is the buyer’s

sole responsibility to determine the suitability of this product for the intended use prior to

purchase. Some states do not allow limitations on warranties, so some or all of the above

limitation may apply to you.

The software supplied is to be used by the purchasing customer only. Providing this

software to other potential system users will void any warranty and assistance. Software

included with this equipment is intended (but not guaranteed) to run on any Windows95®

(or higher)-based computer, and is provided solely for the convenience of the buyer. It is

supplied as-is, and is expressly excluded from any warranty.

There are no user-serviceable parts inside the system.

Remove the cover will void the warranty.

This warranty shall not apply to defects caused by improper or inadequate maintenance,

calibration, modification, repair and unauthorized alteration and unreasonable use by the

user. Also, abuse, neglect, accident, damage in shipment to Mercury United for repair and

operation outside the environmental specifications of the product are not applied. Mercury

United shall make the evaluation of the unit and shall be the sole determiner of it eligibility

for or exclusion from warranty coverage.

SAFETY SUMMARY

The following general safety precaution must be observed during all phases of operation,

service, and repair of this equipment. Failure to comply with these precautions or with

specific warnings elsewhere in this manual violates safety standards of design,

manufacture and intended use of the instrument. Mercury United assumes no liability for

the customer’s failure to comply with these requirements.

GROUNDING THE INSTRUNMENT

To minimize the shock hazard, the instrument chassis and cabinet must be connected to an

electrical ground. The power cable must be plugged into either an approved receptacle or

adaptor with the grounding wire (green or green/yellow) firmly connected to an electrical

ground (safety ground) at the power outlet.

DO NOT OPERATE IN AN EXPLOSIVE ATMOSHPERE

Do not operate the instrument in the presence of flammable gases or fumes. Operation of

any electrical instrument in such an environment constitutes a definite safety hazard.

KEEP AWAY FROM LIVE CIRCUIT

Operating personnel must not remove instrument covers. Component replacement and

internal adjustments must be made by qualified maintenance personnel. Do not replace

components with power connected. Under certain conditions, dangerous voltages may

exist even with the power cable removed. To avoid injuries, always disconnect power and

discharge circuits before touching them.

DO NOT SERVICE OR ADJUST ALONE

Do not attempt internal service or adjustment unless another person capable of rendering

first aid and resuscitation is present.

DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT

Because of the danger of the introducing additional hazards, do not install substitute parts

or perform any unauthorized modification to the instrument. Return the instrument to

Mercury United for service and repair to ensure that safety features are maintained.

ESD STATEMENT

Electro-static discharge can damage electronic equipment. All components, system parts,

and equipment are carefully handled while at Mercury United factory. Ensure that all ESD

precautions are implemented, including but not limited to: ESD stations, ESD wrist-bands,

ESD mats, etc.

Do not operate or store near strong electrostatic, electromagnetic, magnetic or radioactive

fields.

Mercury United makes every effort to insure that the information in this document is

accurate, but makes no claim to that effect and does not guarantee accuracy. This

information is offered as-is, and Mercury United cannot be held responsible for any

inaccuracies. Specifications, features and operational characteristics of the described

product are subject to change without notice.

copied, photocopied, reproduced, translated, or reproduced to any electronic medium or

machine-readable form without prior written consent from Mercury United Electronics, Inc.

Trademarks

ThunderBolt, TSIP and TSIPCHAT are trademarks of Trimble Navigation Limited. IBM is a

registered trademark of International Business Machines, Inc. MS-DOS and Windows are

trademarks of Microsoft Corporation. Pentium is a trademark of Intel Corporation. All other

brand names are trademarks of their respective holders.

Printed in the United States of America.

WARNING

This equipment is primarily designed to provide precise time and

frequency reference at a fixed site. Although it has GPS position

location capability, using this equipment for navigation is not

recommended. The users understand that GPS receiver can be affected

by numerous sources of error such as satellite geometry, selective

availability, satellite condition, receiver location and electromagnetic

interference. Published accuracy specifications are to be used as a

guide and are not guaranteed.

All GPS receivers are subject to degradation of position and velocity

accuracies under Department of Defense imposed Selective Availability

(SIA)

TABLE OF CONTENTS

SECTION 1: PRODUCT OVERVIEW ------------------------------------------------------------ 1

1.1 The Front Panel at a Glance ------------------------------------------------- 2

1.2 The Rear Panel at a Glance ------------------------------------------------- 3

SECTION 2: UNPACKING ------------------------------------------------------------------------ 4

2.1 Packing list --------------------------------------------------------------------- 4

SECTION 3: INSTALLATION -------------------------------------------------------------------- 5

3.1 Antenna Installation ----------------------------------------------------------- 5

3.2 GPS Frequency Reference Receiver and Distributor Installation ------- 6

3.3 Connection to a Personal Computer ---------------------------------------- 6

3.4 Power Input -------------------------------------------------------------------- 6

3.5 Cable Connections ------------------------------------------------------------ 7

3.6 Software Installation ---------------------------------------------------------- 7

SECTION 4: SYSTEM EXPANSION ------------------------------------------------------------- 9

4.1 If More than 6 Frequency References Are Required---------------------- 9

SECTION 5: MAINTENACE ---------------------------------------------------------------------- 10

SECTION 6: IN CASE OF DIFFICULTY --------------------------------------------------------- 10

6.1 Contacting Mercury United --------------------------------------------------- 10

6.2 Returning Equipment for Repair --------------------------------------------- 11

APPENDIX A – SPECIFICATIONS --------------------------------------------------------------- 12

Receiver ------------------------------------------------------------------------- 12

10.0 MHz Outputs (Output Channel 1 ~ Channel 6) ----------------------- 12

1 PPS Output -------------------------------------------------------------------- 12

GPS Antenna -------------------------------------------------------------------- 12

RS-232 Serial Communications --------------------------------------------- 13

Environmental Specifications ------------------------------------------------- 13

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SECTION 1: PRODUCT OVERVIEW

Mercury MG73-A GPS Frequency Reference Receiver and Distributor is a complete

GPS time and frequency system offering multiple 10 MHz outputs all locked to the U.S. Naval

Observatory via the NAVSTART Global Positioning System (GPS) for the purpose of equipment

frequency calibration. GPS disciplined clock compares the 1 pulse per second (1 PPS) from

the GPS receiver to the 1 PPS derived from a high stability internal SC-cut 10 MHz OCXO

(Oven zed Crystal Clock Oscillator). This instantaneous reference signal is used to provide

continual automatic frequency offsetting, compensating for aging and temperature drift. When

the OCXO is locked to the GPS signal, the frequency accuracy of the 10 MHz signal is better

than 1x10-11 per day, and the 1 PPS signal is synchronized to GPS or UTC within 100 ns.

Its outputs include a 10 MHz frequency reference 1 PPS signal, all synchronized to

GPS (Globe Positioning System) or UTC (Universal Coordinated Time) time. A microprocessor

performs the GPS navigation and a unique algorithm is used for OCXO disciplining. To ensure

the signal integrity, satellites tracking and frequency offset results are displayed on a PC

monitor through RS-232 interface.

The calibrated 10 MHz signal is fed into the distribution system. Through amplification

and filtering circuitry, additional 6 outputs with BNC connectors can be conveniently accessed.

These signals serve as external references for up to 6 different equipments to be calibrated. To

obtain even more reference signals, any 10 MHz output of MG73A can be fed into the input of

a Mercury MG73-B GPS Frequency Reference Distributor; additional six references from the

MG73-B become available. This means the whole facility requires only one unit of MG73-A

and as many of MG73-B as required. All these signals have identical traceability to the original

GPS disciplined 10 MHz reference.

Features

► GPS-disciplined OCXO (Oven Controlled Crystal Oscillator) with very

low phase noise.

►High spectral-purity 10 MHz sine wave output

►Standard one pulse-per-second (1 PPS) output

►Self-Survey Mode

►RS-232 control interface

►Windows®-based display software

►Front panel LED indicators for power and RF status.

►The system enters holdover mode when GPS is lost.

Applications

►Standards Labs;

►Frequency Calibration for counters, timers and all frequency-related instrumentation.

►Telecoms synchronization and timescale correction to UTC.

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System Architecture

1.1 The Rear Panel at a Glance

Channel 1

Channel 2

Channel 3

Channel 4

Channel 5

Channel 6

GPS Receive

Micro

rocesso

RS-232

D / A

10 MHz OCXO

10 MHz

Distribution

1 PPS output

GPS Antenna Serial I/O

Ventilation grid

Input Power Entry

Module with fuse

and s

are fuse

- 3 -

1.2 The Front Panel at a Glance

n: Power LED s: 10 MHz Output from the GPS receiver

o: R F Detect t: Antenna In

p: 10 MHz Input u: 10 MHz outputs from the frequency distributor

q: RS-232

r: 1 PPS Output

- 4 -

SECTION 2: UNPACKING

Every system includes a packing list showing the contents of the shipment. Upon

receiving the system, the packing list should be checked to make sure that all the

items listed are present and undamaged.

Packing List for Model MG73-A

Item Description Quantity Mercury

Part

Number

√

1 GPS Frequency Reference

Receiver and Distribution unit

1 MG73-A

2 4 ¾ ” coaxial cable with BNC

connector on each end

1 625001

3 Serial cable with DB9

(10’)

1 625002

4 3 ½” floppy disk (Thunderbolt

Monitor software)

1 625003

5 Active GPS antenna 1 625004

6 3 plug power cord 1 625005

7 MG-73A user’s guidel 1 625006

Other items required for complete installation by not supplied with the MG73-A system

1. RG-59 antenna cable with F connector on each end: Keep total length under 75

feet (22.5 meters).

2. Antenna pole: Threaded ¾” pipe

3. Antenna mounting base. Threaded pipe flange

4. Personal computer. 100 MHz or faster Pentium-II (or higher) based PC with at least

16 bit color.

- 5 -

SECTION 3: INSTALLATION

3.1 Antenna Installation

Choose an Antenna Location

To obtain the best performance possible form the unit, the location of the antenna is critical.

Ideal antenna location is in a good location where the antenna can “see” clear or have the best

possible view of the sky to view the most satellites. Be sure that satellite signal reception is not

interfered by the radio transmission, noise sources or building structure. Roof top is

recommended. Getting the maximum number of satellites in view will get the best performance

of the system.

The GPS active antenna is designed primarily for stationary applications and to be mounted

permanently at roof-top or a high point of a fixed-site. If a full view of the sky is not possible,

mount the antenna aiming towards the equator to maximize the southern view of the sky, in

Southern Hemisphere choose a northern view. The antenna is weatherproof and waterproof

and can withstand exposure to extreme temperatures. Antenna mounting can be a flush

mounting or pole mounting. Mounting standoffs can be found at most marine stores. If

standoffs are not available, the antenna can be mounted on a ¾” pipe with 14 threads per inch.

The ¾” pipe can then be mounted on a pipe flange. The ¾” pipe and flange can be found at

most of hardware stores.

Recommended hardware for antenna assembly:

1. RG-59 antenna cable with male “F” connectors attached to both ends (not provided):

Keep the cable length less than 75 feet (22.5 meters). Be sure that the center

conductor is solid type as opposed to stranded type. When sizing the length of the

cable make sure to include enough slack for a service loop.

2. Antenna pole (not provided): Threaded ¾” pipe

3. Threaded pipe flange (not provided).

Step 1: Route the cable inside the pole (for extra protection and reliability) and connect

the cable to the threaded socket in the base of the antenna.

Step 2: Connect the end of the antenna cable (with “F” connector) to the “ANT. IN”

male connector located on the front panel of the GPS Frequency Reference Receiver

and Distributor.

- 6 -

An example of a finished antenna assembly is shown below

3.2 GPS Frequency Reference Receiver and Distributor Installation

There are no special requirements for the location of the unit itself. Keep the unit away

from electromagnetic interference, strong radio frequency energy such as radio transmitter

cable and antennas. Also, provide adequate clearance around the unit. Do not block the

ventilation grid. The internally generated heat can be dissipated by natural air convection.

3.3 Connection to a Personal Computer

The unit is connected to a personal computer by means of the HD-9 D-sub connector

located on the front of the unit. You can use a longer serial cable (up to 50 feet), but make sure

that is fully shielded in order to prevent unwanted radiation from the cable. If the serial port on

your computer has a DB25 connector in stead of a DB9 connector, use a DB9 to DB25 adaptor.

Use a gender changer if necessary. If you plan to use a port other than COM1, make a note of

the port you choose so that you can set the software to match.

The default serial port configuration is 9600 baud, no parity, 8 bit and 1 stop/start bit.

3.4 Power Input

Use the 3 prong power cord provided to provide 100 to 120 VAC±10% 50 or 60 Hz to

the power entry module on the back panel of the system.

The “PWR” green color LED is on. If not, check the fuse inside the power entry module.

A spare fuse is provided inside the same module. Leave the power on unless you are not going

to be using the equipment for an extended period of time.

- 7 -

3.5 Cable Connection (all connectors are at front panel)

Step 1: Make sure the antenna cable is connected to “ANT. IN” and the “RF

Det.” red color LED is on. If not, check the antenna assembly.

Step 2: Connect the 4 3/4” short coaxial

cable with BNC connectors from

“ANT. OUT” to “10 MHz IN”.

Step 3: Connect the serial cable from “RS 232” to the serial port of the

computer.

3.6 Software Installation

Install the “ThunderBolt Monitor Program” to monitor the performance of the GPS

receiver. PC requirement: Windows 95 (or later) or NT

Step 1: Turn on your personal computer and open Windows® Explorer.

Step 2: Insert the 3 ½” floppy disc in the drive “A” of your computer

Step 3: Select drive A and copy Tboltmon.exe file to a directory of your choice

in your hard disc. To launch the software, go to that directory and click

Tboltmon.exe. Serial Port Selection window is displayed.

Step 4: Select COM 1. If COM1 port is not available, you will need to choose

another communication port that is open and available.

Step 5: The following power-up sequence occurs when the unit starts from

cold.

5.1. Com port indicator changes color from yellow to green and Tx

Rx indicators turn green and blink. The unit is now searching

for satellites. Observe the Signal Levels window and watch as

the unit finds the satellites as indicated by the green SV bars

and AMU being displayed.

- 8 -

5.2 Disciplining Status changes as more satellite signals acquired

Mode: (1) power-up Activity: (6) inactive

Mode: (1) power-up Activity: (1) Osc Warm-up

When enough satellites have been found and their ephemeris

data collected:

Mode: (1) power-up Activity: (2) Frequency Locking

Mode: (1) power-up Activity: (8) Recovery Loop

Mode: (0) Normal Activity: (4) Filter Init

Mode: (0) Normal Activity: (0) Phase Locking

Step 6: When “Critical Alarms” and “Minor Alarms all turn green and “GPS

Status” shows (0) Doing Fixes, the system is ready.

TSIPCHAT is a DOS based program using TSIP (Trimble’s Standard Interface Protocol) for the

system programmers to change the port settings, send commands and gather reports. Please

contact Mercury United if you plan to interface to the receiver. For frequency reference

application, the monitor program displays the most necessary information of the system

parameters.

- 9 -

SECTION 4: SYSTEM EXPANSION

4.1 If More than 6 Frequency References Are Required

You can obtain more frequency references by cascading MG73-A with a MG73-B. MG73-B is

just like a MG73-A without the GPS receiver capability. 10 MHz signal from any output channel

of MG73-A (channel 1 thru channel 6) can be fed into the “10 MHz IN” of the MG73-B.

Additional 6 channels become available. Furthermore, any output of MG73-B (channel 1 thru

channel 6) can also serve the same purpose to keep expanding. Lab tests have shown that no

signal degradation noticed even up to 10 cascading. This means the whole facility requires

only one unit of MG73-A but you can have as many of MG73-B units as you need. All these

signals have identical traceability to the original GPS disciplined 10 MHz reference.

- 10 -

SECTION 5: MAINTENANCE

Mercury MG73-A GPS Frequency Reference Receiver and Distributor provides years of

maintenance-free operation. Should the system experience a problem, the monitor program

and the LEDs on the front panel provide visual warning. Contact Mercury United for technical

support to remove the problem.

There are no user-serviceable parts inside the system. Remove the cover will void the warranty.

It is extremely unusual that the user needs to open the cover to service the unit.

SECTION 6 – IN CASE OF DIFFICULTY

Should you have difficulty with the installation or operation of your MG73-A, please take a few

minutes to look through this manual. You will find the answers to most of your questions here.

If you are still having difficulty after reviewing the manual, please contact us for technical

support and assistance.

6.1 CONTACTING MERCURY UNITED

If you need to contact Mercury United, please telephone, fax or write to us at

Mercury United Electronics, Inc.

10823 Edison Court

Rancho Cucamonga, California 91730 U.S.A.

Tel: (909) 466-0427

FAX: (909) 466-0762

E-mail:sales-us@mercury-crystal.com

Before you call, please have the following information available so that we may better assist

you in trying to resolve the problem immediately:

1. Model number and serial number of the unit

2. Purchase date

3. The company or store name where is the equipment was purchased from.

4. An accurate description of the problem.

- 11 -

6.2 RETURNING EQUIPMENT FOR REPAIR

Should it become necessary for you to return equipment for repair, please take the following

steps:

1. Contact us to obtain a Return Authorization (RMA) number. We can accept repair

returns that have an RMA assigned.

2. Carefully pack the equipment and clearly mark the RMA number on the outside of

the package.

3. Ship the package freight or postage prepaid to the above address. Be sure to

include any items or accessories that we have asked to have included and any

information that may be helpful in resolving the problem. Also be sure to include

your name and information on how to contact you so that we can get additional

information from you if needed and let you know when the equipment has been

repaired.

- 12 -

APPENDIX A: SPECIFICATIONS

The specifications and characteristics of the MG73-A GPS Frequency Reference Receiver and

Distributor are provided in this appendix.

Receiver

L1 frequency Carrier (1575.42 MHz), Coarse /Acquisition code (SpS), 8-channel continuous

tracking with C/N of 35 to 60 dB typical.

1 Hz update rate

1 PPS Accuracy : GPS or UTC 20 nano seconds (one sigma)

1 PPS Output: TTL levels into 50 ohm. 10 microseconds-wide pulses with the leading edge

synchronized to GPS or UTC within 20 nanoseconds (one sigma).

10.0 MHz Outputs (Output Channel 1 ~ Channel 6)

Output Wave Form: Sinusoidal

Output Level: 12.5 dBm±2.5 dBm. into 50 Ω.

6 channels. BNC connectors.

Output Wave Form: Sine wave

SSB Phase Noise: -120 dBc/Hz at 10 Hz offset

-135 dBc/Hz at 100 Hz offset

-135 dBc/Hz at 1 KHz offset

-145 dBc/Hz at 10 KHz offset

-145 dBc/Hz at 100 KHz offset

Harmonic Level: -40 dBc max.

Spurious: -70 dBc max.

Short Term Stability: ≤5E-12

Aging: None. Corrected by GPS

Temperature Effect: None. Corrected by GPS

Frequency Accuracy: 1E-11 or better (one-day average)

1 PPS Output

Time Format: 1 pulse / sec

Time Accuracy: ≤±100 ns relative to UTC (95%)

Output Level: TTL level

Pulse Width: 10 µs

Connector: BNC-socket

GPS Antenna

Fixed site, roof-top, stationary, jam resistant active antenna.

Weatherproof and waterproof.

Characteristic: Hemispherical

Output Impedance: 50 Ω

Connector: “F” type

Size: 3.05” D x 2.61” H (77.5 mm x 66.2mm)

- 13 -

Frequency: L1 1575.42 MHz±1.023 MHz

Polarization: Right-hand circular polarization (RHCP)

VVSWR: 2.0 max.

Axial Ratio: 90°: 4.0 dB maximum: 10°: 6 dB max.

Gain: 35 dB ±3 dB

Noise: 3.3 dB max. (25°C±5°C)

Pass-band width: 50 MHz

Azimuth Coverage: 360°(omni-directional)

Elevation Coverage: 0° to 90° elevation (hemispherical)

Power: +5.0 V D.C.. Powered via RF-coaxial cable

Mounting: ¾” pipe thread

Weight: 6 0 oz (170 grams)

Enclosure: Off-white plastic

Operating Temperature: -40°C to +85°C

Storage Temperature: -40°C to +100°C

Shock: 50 g vertical, 30 g all axes

Vibration: 10~200 Hz Log sweep 3 g (sweep time 30 minutes 3 axes

Humidity: Mil-STD-810E

Corrosion: 5% salt spray

Waterproof: Immersion to 1 meter

RS 232 Serial Communications

The default communication settings for the system are:

Baud rate: 9600

Parity: None

Data bits: 8

Stop bits: 1

Pacing: None

Echo: OFF

Connector: DB-9. Pin configuration

Pin 1, pin 4, pin 6, pin 7, pin 8 and pin 9: Not used

Pin 2: TxD. Transmit out

Pin 3: RxD. Receive in

Pin 5: Ground

Environmental Specifications

Power Supply: 115 / 125V ±10% AC

Operating Temperature: 0°C ~ +60°C

Storage Temperature: -40°C ~ +85°C

Operating Humidity: 95% non-condensing

Maximum Altitude: 18,000 m

Weight: approx. 8.5 Kgs (18.7 ib)

Physical Dimensions: 12”(W) x 8”(L) x 4 -1/4”(H); 305 mm (W) x 203 mm (L) x 108 mm (H)

Power Consumption: 16 watts at warm-up. 10 watts at steady state.