Tektronix 1503c schematic

User Manual

1503C Metallic Time-Domain Reflectometer

070-7323-05

This document applies to firmware version 5.04 and above.

www.tektronix.com

Copyright © T ektronix, Inc. All rights reserved. T ektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes

that in all previously published material. Specifications and price change privileges reserved. T ektronix, Inc., P.O. Box 500, Beaverton, OR 97077 TEKTRONIX and TEK are registered trademarks of T ektronix, Inc.

WARRANTY

T ektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment. If a product proves defective during this warranty period, T ektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in exchange for the defective product.

In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for packaging and shipping the defective product to the service center designated by T ektronix, with shipping charges prepaid. T ektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the T ektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any other charges for products returned to any other locations.

This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate maintenance and care. T ektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting from attempts by personnel other than T ektronix representatives to install, repair or service the product; b) to repair damage resulting from improper use or connection to incompatible equipment; c) to repair any damage or malfunction caused by the use of non-T ektronix supplies; or d) to service a product that has been modified or integrated with other products when the effect of such modification or integration increases the time or difficulty of servicing the product.

THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO REP AIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY . TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT , SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

List of Figures iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of Tables vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Information vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installation and Repacking viii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Contacting T ektronix x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Safety Summary xiii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Instructions 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overview 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preparing to Use the 1503C 1–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Display 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Front-Panel Controls 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Menu Selections 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T est Preparations 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cable T est Procedure 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Additional Features (Menu Selected) 1–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operator Tutorial 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

What is the Tektronix 1503C? 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

How Does It Do It? 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

You, the Operator 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Menus and Help 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Getting Started 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The Waveform Up Close 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A Longer Cable 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Noise 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Set Ref (∆ Mode) 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VIEW INPUT 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

STORE and VIEW STORE 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VIEW DIFF 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1503C MTDR User Manual

Table of Contents

Menu-Accessed Functions 2–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TDR Questions and Answers 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Options and Accessories 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 04: YT–1 Chart Recorder 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 05: Metric Default 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 06: Ethernet) 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 07: YT–1S Chart Recorder 3–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 08: T oken Ring Adapter 3–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 09: Universal Service Ordering Code 3–18. . . . . . . . . . . . . . . . . . . . . . . . . . .

Option 10: T oken Ring Interface 3–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power Cord Options 3–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Accessories 3–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix A: Specifications A–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical Characteristics A–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Environmental Characteristics A–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Certifications and Compliances A–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Physical Characteristics A–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix B: Operator Performance Checks B–1. . . . . . . . . . . . . .

Appendix C: Operator Troubleshooting C–1. . . . . . . . . . . . . . . . . .

Error Messages C–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Appendix D: Application Note D–1. . . . . . . . . . . . . . . . . . . . . . . . . .

Glossary Glossary–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Index Index–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1503C MTDR User Manual

List of Figures

Table of Contents

Figure 1–1: Rear Panel Voltage Selector, Fuse, AC Receptacle 1–1. . . . . . . .

Figure 1–2: Display Showing Low Battery Indication 1–3. . . . . . . . . . . . . . .

Figure 1–3: 1503C Front-Panel Controls 1–4. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–4: Display and Indicators 1–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–5: Vp Set at .30, Cursor Beyond Reflected Pulse

(Setting Too Low) 1–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–6: Vp Set at .99, Cursor Less Than Reflected Pulse

(Setting Too High) 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–7: Vp Set at .66, Cursor on Rising Edge of Reflected

Pulse (Set Correctly) 1–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–8: 20-ft Cable at 5 ft/div 1–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–9: Short in the Cable 1–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–10: Open in the Cable 1–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–11: 455-ft Cable 1–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–12: 455-ft Cable with 20 ft/div, Cursor Off Screen 1–15. . . . . . . . . .

Figure 1–13: Return Loss 1–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–14: Reflection Adjusted to One Division in Height 1–16. . . . . . . . . .

Figure 1–15: Display with VIEW INPUT Turned Off 1–17. . . . . . . . . . . . . . .

Figure 1–16: Display of a Stored Waveform 1–18. . . . . . . . . . . . . . . . . . . . . . .

Figure 1–17: Display of a Stored Waveform and Current Waveform 1–18. . . .

Figure 1–18: Display of a Stored Waveform, Current Waveform,

and Difference Waveform 1–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–19: Waveform Moved to Top Half of Display 1–19. . . . . . . . . . . . . .

Figure 1–20: Current Waveform Centered, Stored

Waveform Above 1–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–21: Current Waveform Center, Stored Waveform

Above, Difference Below 1–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–22: Waveform of Three-Foot Lead-in Cable 1–21. . . . . . . . . . . . . . .

Figure 1–23: Cursor Moved to End of Three-Foot Lead-in Cable 1–22. . . . . .

Figure 1–24: Cursor Moved to End of Three-Foot Lead-in Cable 1–22. . . . . .

Figure 1–25: Cursor Moved to 0.00 ft 1–23. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–26: Incident Pulse at Four Divisions, FILTER at

Desired Setting 1–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 1–27: Waveform Viewed in Normal Operation 1–24. . . . . . . . . . . . . . .

Figure 1–28: Waveform Showing Intermittent Short 1–25. . . . . . . . . . . . . . . .

Figure 1–29: Waveform Display with No Outgoing Pulses 1–25. . . . . . . . . . .

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Figure 1–30: A Captured Single Sweep 1–26. . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–1: Display Showing 10-ft Cable in Start-Up Conditions 2–2. . . . . .

Figure 2–2: Cursor of Rising Edge of Reflected Pulse 2–3. . . . . . . . . . . . . . .

Figure 2–3: Waveform with VERT SCALE Increased Showing

an Open 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–4: Waveform with Short 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–5: 10-foot Cable with Cursor at Far Left 2–4. . . . . . . . . . . . . . . . . .

Figure 2–6: 10-foot Cable with Cursor at Incident Pulse 2–5. . . . . . . . . . . . .

Figure 2–7: 10-foot Cable with Cursor at Incident Pulse, Vertical

Scale at 25 dB 2–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–8: Cursor on End of Longer Cable 2–6. . . . . . . . . . . . . . . . . . . . . . .

Figure 2–9: Scrolling Down the Cable 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–10: Pulse Width at 2 ns 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–11: Pulse Width at 10 ns 2–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–12: Pulse Width at 100 ns 2–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–13: Pulse Width at 1000 ns, Longer than the Cable

Being Tested 2–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–14: Noise on the Waveform. 2–9. . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–15: Noise Reduced. 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–16: Noise Reduced to Minimum 2–10. . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–17: Incident and Reflected Pulses with Cursor at 0.00 ft 2–11. . . . . .

Figure 2–18: Incident and Reflected Pulses with Cursor at 10.0 ft 2–12. . . . . .

Figure 2–19: New Zero Set at End of Test Cable 2–12. . . . . . . . . . . . . . . . . . .

Figure 2–20: Display with 10-ft Cable and NOISE FILTER turned to

VERT SET REF 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–21: VERT SCALE adjusted to Make Pulse Two Divisions

High 2–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–22: Filter Returned to Desired Setting 2–14. . . . . . . . . . . . . . . . . . . .

Figure 2–23: Display with VIEW INPUT Turned Off 2–15. . . . . . . . . . . . . . .

Figure 2–24: Display with VIEW INPUT Turned On 2–15. . . . . . . . . . . . . . .

Figure 2–25: Waveform Moved to Upper Portion of the Display 2–16. . . . . . .

Figure 2–26: Waveform with Cable Shorted 2–16. . . . . . . . . . . . . . . . . . . . . . .

Figure 2–27: Waveform with Both Current and Stored Waveforms 2–17. . . . .

Figure 2–28: Stored, Current, and Difference Waveforms 2–17. . . . . . . . . . . .

Figure 2–29: Display with VIEW STORE and VIEW DIFF Disabled. 2–19. .

Figure 2–30: Short and Open Viewed via Max Hold 2–19. . . . . . . . . . . . . . . .

Figure 2–31: Waveform Strobed Down Display in Max Hold 2–19. . . . . . . . .

Figure 2–32: Display with Pulse Turned Off 2–21. . . . . . . . . . . . . . . . . . . . . .

1503C MTDR User Manual

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Figure 2–33: Test Cable 2–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–34: Shorted Test Cable with a Captured Single Sweep 2–22. . . . . . .

Figure 3–1: A Typical Ethernet System 3–3. . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–2: N-Type Male T-Connector 3–5. . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–3: N-Type Female T-Connector 3–6. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–4: System 1 – Tap Hidden by Traffic

(1 avg, 50 ft/div. 35 dB) 3–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–5: System 1 – Traffic and Tap Nearly Identical

(4 avg, 50 ft/div, 35 dB) 3–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–6: System 1 – Tap Becoming Visible

(16 avg, 50 ft/div, 35 dB) 3–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–7: System 1 – Tap Quite Visible

(128 avg, 50 ft/div, 35 dB) 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–8: System 1 – No Traffic

(1 avg, 50 ft/div, 35 dB) 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–9: System 1 – Tap Expanded, No Traffic

(1 avg, 2 ft/div, 35 dB) 3–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–10: System 2 – Cable w/ Revision One Repeater

(1 avg, 200ft/div, 2.25dB) 3–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–11: System 2 – First Tap, No Traffic

(1 avg, 1 ft/div, 44.5 dB) 3–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–12: System 2 – Same Tap with 5% Traffic

(1 avg, 1 ft/div, 44.5 dB) 3–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–13: System 2 – Same Tap, Increased Averaging

(16 avg, 1 ft/div, 44.5 dB) 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–14: System 2 – Farther Out, More Gain

(128 avg, 10 ft/div, 53.5 dB) 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–15: System 2 – 1000-ft Cable at 10 ns

(128 avg, 100 ft/div, 43.75 dB) 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–16: System 2 – Previous Waveform Expanded

(128 avg, 20 ft/div, 54.75 dB) 3–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–17: System 2 – Next Group of Taps

(128 avg, 20 ft/div, 54.75 dB) 3–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–18: System 2 – Group of Taps Expanded

(128 avg, 10 ft/div, 54.75 dB) 3–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–19: System 2 – Another Group of Taps

(128 avg, 10 ft/div, 54.75 dB) 3–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–20: System 2 – End of Cable (128 avg, 20 ft/div, 61.25 dB) 3–16. . . Figure 3–21: Typical Frequency Response Curve with Ethernet

Option 06 3–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1503C MTDR User Manual

Table of Contents

Figure B–1: Start-up Measurement Display B–2. . . . . . . . . . . . . . . . . . . . . . .

Figure B–2: Measurement Display with 10-foot Cable B–2. . . . . . . . . . . . . .

Figure B–3: Cursor at End of 10-foot Cable B–3. . . . . . . . . . . . . . . . . . . . . . .

Figure B–4: Cursor at End of 10-foot Cable, Vp Set to .30 B–3. . . . . . . . . . .

Figure B–5: Flatline Display Out to 50,0000+ Feet B–4. . . . . . . . . . . . . . . . .

Figure B–6: Waveform Off the Top of the Display B–4. . . . . . . . . . . . . . . . . .

Figure B–7: Waveform at the Bottom of the Display B–4. . . . . . . . . . . . . . . .

Figure B–8: Waveform with Gain at 57 dB B–5. . . . . . . . . . . . . . . . . . . . . . . .

Figure B–9: Distance at –2.00 ft B–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure B–10: Pulse Adjusted to Four Major Divisions in Height B–7. . . . . . .

Figure B–11: Waveform Centered, Cursor at 10.00 ft B–8. . . . . . . . . . . . . . .

Figure B–12: Pulse Adjusted to Four Major Divisions in Height B–8. . . . . . .

Figure B–13: Aberrations Less Than Four Divisions Out to 30.00 ft B–9. . . .

Figure B–14: Pulse Adjusted to Four Major Divisions in Height B–9. . . . . . .

Figure B–15: Aberrations Less Than Four Divisions Out to 300.00 ft B–10. . .

Figure B–16: Pulse Adjusted to Four Major Divisions in Height B–10. . . . . . .

Figure B–17: Aberrations Less Than Four Divisions Out to

3000.00 ft B–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of Tables

Shipping Carton Test Strength ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fuse and Voltage Ratings 1–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vp of Various Dielectric Types 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Impedance of Various Cable Types 1–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Suggested Pulse and Ft/Div for Cable Lengths 1–13. . . . . . . . . . . . . . . . . . . . . . . . . .

Option 06 Electrical Characteristics 3–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical Characteristics A–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Environmental Characteristics A–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Certifications and Compliances A–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Physical Characteristics A–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1503C MTDR User Manual

General Information

Product Description

Battery Pack

Options

The Tektronix 1503C Metallic-cable Time-Domain Reflectometer (MTDR) is a cable test instrument that uses radar principles to determine the electrical characteristics of metallic cables.

The 1503C generates a half-sine wave signal, applies it to the cable under test, and detects and processes the reflected voltage waveform. These reflections are displayed in the 1503C liquid crystal display (LCD), where distance measurements may be made using a cursor technique. Impedance information may be obtained through interpreting waveform amplitude.

The waveform may be temporarily stored within the 1503C and recalled or may be printed using the optional dot matrix strip chart recorder, which installs into the front-panel Option Port.

The 1503C may be operated from an AC power source or an internal lead-acid battery that supply a minimum of five hours operating time (see the Specifications appendix for specifics).

Options available for the 1503C are explained in the Options and Accessories chapter of this manual.

Standards, Documents,

and References Used

Changes and History

Information

1503C MTDR User Manual

Terminology used in this manual is in accordance with industry practice. Abbreviations are in accordance with ANSI Y1.1–19722, with exceptions and additions explained in parentheses in the text. Graphic symbology is based on ANSI Y32.2–1975. Logic symbology is based on ANSI Y32.14–1973 and manufacturer’s data books or sheets. A copy of ANSI standards may be obtained from the Institute of Electrical and Electronic Engineers, 345 47th Street, New York, NY 10017.

Changes that involve manual corrections and/or additional data will be incorporated into the text and that page will show a revision date on the inside bottom edge. History information is included in any diagrams in gray.

vii

General Information

Installation and Repacking

Unpacking and InItial

Inspection

Power Source and Power

Requirements

Before unpacking the 1503C from its shipping container or carton, inspect for signs of external damage. If the carton is damaged, notify the carrier. The shipping carton contains the basic instrument and its standard accessories. Refer to the replaceable parts list in the Service Manual for a complete listing.

If the contents of the shipping container are incomplete, if there is mechanical damage or defect, or if the instrument does not meet operational check requirements, contact your local T ektronix Field Office or representative. If the shipping container is damaged, notify the carrier as well as Tektronix.

The instrument was inspected both mechanically and electrically before shipment. It should be free if mechanical damage and meet or exceed all electrical specifications. Procedures to check operational performance are in the Performance Checks appendix. These checks should satisfy the requirements for most receiving or incoming inspections.

The 1503C is intended to be operated from a power source that will not apply more than 250 volts RMS between the supply conductors or between either supply conductor and ground. A protective ground connection, by way of the grounding conductor in the power cord, is essential for safe operation.

The AC power connector is a three-way polarized plug with the ground (earth) lead connected directly to the instrument frame to provide electrical shock protection. If the unit is connected to any other power source, the unit frame must be connected to earth ground.

viii

Power and voltage requirements are printed on the back panel. The 1503C can be operated from either 115 VAC or 230 VAC nominal line voltage at 45 Hz to 440 Hz, or a battery pack.

Further information on the 1503C power requirements can be found in the Safety Summary in this section and in the Operating Instructions chapter.

1503C MTDR User Manual

General Information

Repacking for Shipment

When the 1503C is to be shipped to a T ektronix Service Center for service or repair, attach a tag showing the name and address of the owner, name of the individual at your firm who may be contacted, the complete serial number of the instrument, and a description of the service required. If the original packaging is unfit for use or is not available, repackage the instrument as follows:

1. Obtain a carton of corrugated cardboard having inside dimensions that are at

least six inches greater than the equipment dimensions to allow for cushioning.

The test strength of the shipping carton should be 275 pounds (102.5 kg). Refer

to the following table for test strength requirements:

SHIPPING CARTON TEST STRENGTH

Gross Weight (lb) Carton Test Strength (lb)

0 – 10 200

11 – 30 275

31 – 120 375 121 – 140 500 141 – 160 600

2. Install the front cover on the 1503C and surround the instrument with

polyethylene sheeting to protect the finish.

3. Cushion the instrument on all sides with packing material or urethane foam

between the carton and the sides of the instrument.

4. Seal with shipping tape or an industrial stapler. If you have any questions, contact your local Tektronix Field Office or

representative.

1503C MTDR User Manual

General Information

Contacting Tektronix

Phone 1-800-833-9200*

Address Tektronix, Inc.

Department or name (if known) 14200 SW Karl Braun Drive P.O. Box 500 Beaverton, OR 97077 USA

Web site www.tektronix.com

Sales support 1-800-833-9200, select option 1*

Service support 1-800-833-9200, select option 2*

Technical support Email: support@tektronix.com

1-800-833-9200, select option 3* 1-503-627-2400

6:00 a.m. – 5:00 p.m. Pacific time

* This phone number is toll free in North America. After office hours, please leave a

voice mail message. Outside North America, contact a Tektronix sales office or distributor; see the Tektronix web site for a list of offices.

1503C MTDR User Manual

General Safety Summary

Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it. To avoid potential hazards, use this product only as specified.

Only qualified personnel should perform service procedures.

To Avoid Fire or Personal Injury

Power Source

Use Proper Power Cord. Use only the power cord specified for this product and

certified for the country of use. Use Proper V oltage Setting. Before applying power, ensure that the line selector is

in the proper position for the power source being used.

This product is intended to operate from a power source that will not apply more than 250 volts RMS between the supply conductors or between the supply conductor and ground. A protective ground connection, by way of the grounding conductor in the power cord, is essential for safe operation.

Ground the Product. This product is grounded through the grounding conductor of the power cord. To avoid electric shock, the grounding conductor must be connected to earth ground. Before making connections to the input or output terminals of the product, ensure that the product is properly grounded.

The standard power cord (161-0288-00) is rated for outdoor use. All other optional

power cords are rated for indoor use only.

Observe All Terminal Ratings. To avoid fire or shock hazard, observe all ratings and markings on the product. Consult the product manual for further ratings information before making connections to the product.

Do not apply a potential to any terminal, including the common terminal, that exceeds the maximum rating of that terminal.

1503C MTDR User Manual

Replace Batteries Properly. Replace batteries only with the proper type and rating specified.

Recharge Batteries Properly. Recharge batteries for the recommended charge cycle only.

Use Proper AC Adapter. Use only the AC adapter specified for this product. Do Not Operate Without Covers. Do not operate this product with covers or panels

removed.

Use Proper Fuse. Use only the fuse type and rating specified for this product. Avoid Exposed Circuitry. Do not touch exposed connections and components

when power is present.

General Safety Summary

Do Not Operate With Suspected Failures. If you suspect there is damage to this product, have it inspected by qualified service personnel.

Do Not Operate in an Explosive Atmosphere.

Symbols and Terms

T erms in this Manual. These terms may appear in this manual:

WARNING. Warning statements identify conditions or practices that could result in injury or loss of life.

CAUTION. Caution statements identify conditions or practices that could result in damage to this product or other property.

T erms on the Product. These terms may appear on the product: DANGER indicates an injury hazard immediately accessible as you read the

marking. WARNING indicates an injury hazard not immediately accessible as you read the

marking. CAUTION indicates a hazard to property including the product.

Symbols on the Product. The following symbols may appear on the product:

xii

Battery Recycling

CAUTION

Refer to Manual

WARNING

High Voltage

Double

Insulated

Protective Ground

(Earth) Terminal

This product contains a Nickel Cadmium (NiCd) battery, which must be recycled or disposed of properly. For the location of a local battery recycler in the U.S. or Canada, please contact:

RBRC (800) BATTERY Rechargeable Battery Recycling Corp. (800) 227-7379 P.O. Box 141870 www.rbrc.com Gainesville, Florida 32614

1503C MTDR User Manual

Operating Instructions

Overview

Handling

Powering the 1503C

The 1503C front panel is protected by a watertight cover, in which the standard accessories are stored. Secure the front cover by snapping the side latches outward. If the instrument is inadvertently left on, installing the front cover will turn off the POWER switch automatically.

The carrying handle rotates 325° and serves as a stand when positioned beneath the instrument.

The 1503C can be stored in temperatures ranging from –62° C to +85° C if a battery is not installed. If a battery is installed and the storage temperature is below –35° C or above +65° C, the battery pack should be removed and stored separately (see 1503C Service Manual for instructions on removing the battery). Battery storage temperature should be between –35° C to +65° C.

In the field, the 1503C can be powered using the internal battery . For AC operation, check the rear panel for proper voltage setting. The voltage selector can be seen through the window of the protective cap. If the setting differs from the voltage available, it can be easily changed. Simply remove the protective cap and select the proper voltage using a screwdriver.

1503C MTDR User Manual

REMOVE

CAP TO SELECT

VOLTAGE

REMOVE CAP TO

REPLACE

FUSE

Voltage

Selector

Line Fuse

AC Power

Cord Receptacle

Figure 1–1: Rear Panel Voltage Selector, Fuse, AC Receptacle

1–1

Operating Instructions

The 1503C is intended to be operated from a power source that will not apply more than 250 V RMS between the supply conductors or between either supply conductor and ground. A protective ground connection by way of the grounding conductor in the power cord is essential for safe operation.

The AC power connector is a three-way polarized plug with the ground (earth) lead connected to the instrument frame to provide electrical shock protection. If the unit is connected to any other power source, the unit frame must be connected to an earth ground. See Safety and Installation section.

CAUTION. If you change the voltage selector, you must change the line fuse to the appropriate value as listed near the fuse holder and in the table below.

Care of the Battery Pack

Battery Charging

FUSE RATING

250 V NOMINAL RANGE

0.3 A T 115 VAC (90 – 132 VAC)

0.15 A T 230 VAC (180 – 250 VAC)

CAUTION. Read these instructions concerning the care of the battery pack. They contain instructions that reflect on your safety and the performance of the instrument.

The 1503C can be powered by a rechargeable lead-gel battery pack that is accessible only by removing the case from the instrument. When AC power is applied, the battery pack is charged at a rate that is dependent on the battery charge state.

The battery pack will operate the 1503C for a minimum of eight continuous hours (including making 30 chart recordings) if the LCD backlight is turned off.

The battery pack will charge fully in 16 hours when the instrument is connected, via the power cord, to an AC power source with the instrument turned off. The instrument may be turned on and operated while the batteries are charging, but this will increase the charging time. For longest battery life, a full charge is preferred over a partial charge.

VOLTAGE RATING

1–2

For maximum capacity , the batteries should be charged within a temperature range of +20° C to +25° C. However, the batteries can be charged within a temperature range of 0° C to +40° C and operated in temperatures ranging from –10° C to +55° C.

1503C MTDR User Manual

Operating Instructions

CAUTION. Do not charge battery pack below 0° C or above +40° C. Do not discharge battery pack below –10° C or above +55° C. If r emoving the battery pack during or after exposure to these extreme conditions, turn the instrument off and remove the AC power cord.

The battery pack should be stored within a temperature range of –35° C to +65° C. However, the self-discharge rate will increase as the temperature increases.

If the instrument is stored with the battery pack installed, the battery pack should be charged every 90 days. A fully charged battery pack will lose about 12% of its capacity in three to four months if stored between +20° C and +25° C.

Low Battery

If the battery is low, it will be indicated on the LCD (bat/low). If this is the case, protective circuitry will shut down the 1503C within minutes. Either switch to AC power or work very fast. If the instrument is equipped with a chart recorder, using the recorder will further reduce the battery level, or the added load might shut down the instrument.

bat/low 0.00 ft

O N

O F F

50 W 2 ns

1 avg

0.00 dB 5000 ft

Low Battery

Indicator

Figure 1–2: Display Showing Low Battery Indication

Protection circuits in the charger prevent deep discharge of the batteries during instrument operation. The circuits automatically shut down the instrument whenever battery voltage falls below approximately 10 V. If shutdown occurs, the batteries should be fully recharged before further use.

Low Temperature

Operation

1503C MTDR User Manual

NOTE. Turn the POWER switch off after instrument shutdown to prevent continued discharge of the batteries.

When the instrument is stored at temperatures below –10° C, voids might develop in the liquid crystal display (LCD). These voids should disappear if the instrument is placed in an ambient temperature w +5° C for 24 hours.

1–3

Operating Instructions

When operating the 1503C in an environment below +10° C, a heater will activate. The element is built into the LCD module and will heat the display to permit normal operation. Depending on the surrounding temperature, it might take up to 15 minutes to completely warm the crystals in the LCD. Once warmed, the display will operate normally.

Preparing to Use the 1503C

Check the power requirements, remove the front cover, and you are ready to test cables. The following pages explain the front-panel controls.

Tektronix

VIEW

INPUT

VIEW

STORE

VIEW DIFF

STORE

INPUT PROTECTED

400 V PEAK MAX

CABLE

1 3 4 5 6 7

ac 0.00 ft

O N

O F F

50 Ω

IMPEDANCE

1 avg

NOISE FILTER VERT SCALE DIST/DIV

HORZ

SET REF

VERT

1503C

0.00 db

METALLIC TDR

CABLE TESTER

1 ft

2 ns

POSITION

PULSE WIDTH

.03

.02

.01

.04

.05

.06

.07

.08

.09

.00

POWER

(PULL ON)

910

Figure 1–3: 1503C Front-Panel Controls

CAUTION. Do not connect to circuits or cables with live voltages gr eater than 400 V peak. Voltages exceeding 400 V might damage the 1503C front-end circuits.

1–4

1503C MTDR User Manual

Display

Power

Type Cursor Waveform

Operating Instructions

Front-Panel to Cursor

Distance Window

Front-Panel Controls

IMPEDANCE

View Input

Indicator

View Store

Indicator

View Difference

Indicator

Store

Indicator

F O

50 W 2 ns

Selected

Impedance

1 avg

Selected

Noise Filter

0.00 dB 5000 ft

Selected Selected Selected

Vertical Scale Distance per

Division

0.00 ft

Pulse Width

Figure 1–4: Display and Indicators

1. CABLE: A female BNC connector for attaching a cable to the 1503C for

testing.

2. IMPEDANCE: A four-position rotary switch that selects the output impedance

of the cable test signal. Available settings are 50, 75, 93, and 125 Ohms. The selected value is displayed above the control on the LCD.

Grid

NOISE FILTER







VERT SCALE

DIST/DIV

1503C MTDR User Manual

3. NOISE FILTER: If the displayed waveform is noisy, the apparent noise can

be reduced by using noise averaging. A veraging settings are between 1 and 128. The time for averaging is directly proportional to the averaging setting chosen. A setting of 128 might take the instrument up to 35 seconds to acquire and display a waveform. The first two positions on the NOISE FILTER control are used for setting the vertical and horizontal reference points. The selected value or function is displayed above the control on the LCD.

4. VERT SCALE: This control sets the vertical gain, displayed in dB, or the

vertical sensitivity, displayed in mr per division. Although the instrument defaults to dB, you may choose the preferred mode from the Setup Menu. The selected value is displayed above the control on the LCD.

5. DIST/DIV: Determines the number of feet (or meters) per division across the

display . The minimum setting is 1 ft/div (0.25 meters) and the maximum setting is 5000 ft/div (1000 meters). The selected value is displayed above the control on the LCD.

1–5

Operating Instructions

A standard instrument defaults to ft/div. A metric instrument (Option 05) defaults to m/div, but either may be changed temporarily from the menu. The default can be changed by changing an internal jumper (see 1503C Service Manual and always refer such changes to qualified service personnel).

.4 .5

POWER

(PULL ON)

.03

.02

.01

.9 .00

PULSE WIDTH

POSITION

.04 .05

6. Vp: The two Velocity of Propagation controls are set according to the

.06

.07

.08

.09

propagation velocity factor of the cable being tested. For example, solid polyethylene commonly has a Vp of 0.66. Solid polytetraflourethylene (T eflon ) is approximately 0.70. Air is 0.99. The controls are decaded: the left control is the first digit and the right control is the second digit. For example, with a Vp of 0.30, the first knob would be set to .3 and the second knob to .00.

7. POWER: Pull for power ON and push in for power OFF . When the front cover

is installed, this switch is automatically pushed OFF.

8. PULSE WIDTH: This is a five-position rotary switch that selects the pulse

width of the cable test signal. The available settings are: 2, 10, 100, 1000 nanoseconds, and AUTO. The selected value is displayed on the LCD adjacent to the control. The AUTO setting sets the pulse width according to the distance registered at the right side of the LCD. The selected value is displayed to the left of this control on the LCD.

POSITION: This is a continuously rotating control that positions the

displayed waveform vertically, up or down the LCD.

10.

POSITION: This is a continuously rotating control that moves a vertical

cursor completely across the LCD graticule. In addition, the waveform is also moved when the cursor reaches the extreme right or left side of the display. A readout (seven digits maximum) is displayed in the upper right corner of the LCD, showing the distance from the front panel BNC to the current cursor location.

1–6

VIEW INPUT

VIEW STORE

VIEW

DIFF

STORE

11. MENU: This pushbutton provides access to the menus and selects items chosen

from the menus.

12. VIEW INPUT: When pushed momentarily, this button toggles the display of

the waveform acquired at the CABLE connector. This function is useful to stop displaying a current waveform to avoid confusion when looking at a stored waveform. This function defaults to ON when the instrument is powered up.

13. VIEW STORE: When pushed momentarily, this button toggles the display of

the stored waveform.

14. VIEW DIFF: When pushed momentarily , this button toggles the display of the

current waveform minus the stored waveform and shows the difference between them.

15. STORE: When pushed momentarily, the waveform currently displayed will be

stored in the instrument memory . If a waveform is already stored, pushing this

1503C MTDR User Manual

Menu Selections

Operating Instructions

button will erase it. The settings of the stored waveform are available from the first level menu under View Stored Waveform Settings.

There are several layers of menu, as explained below.

Main Menu

The Main Menu is entered by pushing the MENU button on the front panel.

1. Return to Normal Operations puts the instrument into normal operation

mode.

2. Help with Instrument Controls explains the operation of each control. When

a control or switch is adjusted or pushed, a brief explanation appears on the LCD.

3. Cable Information has these choices: a. Help with Cables gives a brief explanation of cable parameters. b. Velocity of Propagation V alues displays a table of common dielectrics and

their Vp values. These are nominal values. The manufacturer’s listed specifications should be used whenever possible.

c. Impedance Values displays impedances of common cables. In some cases,

these values have been rounded off. Manufacturer’s specifications should be checked for precise values.

d. Finding Unknown Vp Values describes a procedure for finding an

unknown Vp.

4. Setup Menu controls the manner in which the instrument obtains and displays its test results.

1503C MTDR User Manual

a. Acquisition Control Menu has these choices:

i. Max Hold Is: On/Off. Turn Max Hold on by pushing MENU then

STORE. In this mode, waveforms are accumulated on the display . Max Hold can be deactivated by pushing STORE or the mode exited by using the Setup Menu.

ii. Pulse Is: On/Off. T urns the pulse generator of f so the 1503C does not

send out pulses.

iii. Single Sweep Is: On/Off. This function is much like a still camera; it

will acquire one waveform and hold it.

b. Vertical Scale Is: dB/mr. This offers you a choice as to how the vertical

gain of the instrument is displayed. You may choose decibels or millirho. When powered down, the instrument will default to decibels when powered back up.

1–7

Operating Instructions

c. Distance/Div Is: ft/m. Offers you a choice of how the horizontal scale is

displayed. You may choose from feet per division or meters per division. When powered up, the instrument will default to feet unless the internal jumper has been moved to the meters position. Instructions on changing this default are contained in the 1503C Service Manual.

d. Light Is: On/Off. This control turns the electroluminescent backlight

behind the LCD on or off.

5. Diagnostics Menu lists an extensive selection of diagnostics to test the

operation of the instrument.

NOTE. The Diagnostics Menu is intended for instrument repair and calibration. Proper instrument setup is important for correct diagnostics results. Refer to the 1503C Service Manual for more information on diagnostics.

a. Service Diagnostics Menu has these choices:

i. Sampling Efficiency Diagnostic displays a continuous efficiency

diagnostic of the sampling circuits.

ii. Noise Diagnostic measures the internal RMS noise levels of the

instrument.

iii. Impedance Diagnostic tests the output impedance circuits in the

instrument.

iv. Offset/Gain Diagnostic reports out-of-tolerance steps in the program-

mable gain stage. This can help a service technician to quickly isolate the cause of waveform distortion problems.

v. RAM/ROM Diagnostics Menu performs tests on the RAM (Random

Access Memory) and the ROM (Read Only Memory).

vi. Timebase Is: Normal - Auto Correction / Diagnostic - No

Correction. When in Normal - Auto Correction, the instrument

compensates for variations in temperature and voltage. This condition might not be desirable while calibrating the instrument. While in Diagnostic - No Correction, the circuits will not correct for these variations.

b. Front Panel Diagnostics aids in testing the front panel. c. LCD Diagnostics Menu has these choices:

i. LCD Alignment Diagnostic generates a dot pattern of every other

pixel on the LCD. These pixels can be alternated to test the LCD.

1–8

ii. Response Time Diagnostic generates alternate squares of dark and

light, reversing their order. This tests the response time of the LCD and

1503C MTDR User Manual

Operating Instructions

can give an indication of the effectiveness of the LCD heater in a cold environment.

iii. LCD Drive Test Diagnostic generates a moving vertical bar pattern

across the LCD.

iv. Contrast Adjust allows you to adjust the contrast of the LCD. It

generates an alternating four-pixel pattern. The nominal contrast is set internally . When in Contrast Adjust mode, VERT SCALE is used as the contrast adjustment control. This value ranges from 0 to 255 units and is used by the processor to evaluate and correct circuit variations caused by temperature changes in the environment.

d. Chart Diagnostics Menu offers various tests for the optional chart

recorder. i. LCD Chart allows adjusting the number of dots per segment and the

number of prints (strikes) per segment.

ii. Head Alignment Chart generates a pattern to allow mechanical

alignment of the optional chart recorder.

6. View Stored W aveform Settings displays the instrument settings for the stored waveform.

7. Option Port Menu contains three items. T wo items allow configuration of the option port for communicating with devices other than the optional chart recorder and one item test the option port.

a. Option Port Diagnostic creates a repeating pattern of signals at the option

port to allow service technicians to verify that all signals are present and working correctly.

b. Set Option Port Timing allows adjustment of the data rate used to

communicate with external devices. The timing rate between bytes can be set from about 0.05 to 12.8 milliseconds.

c. Option Port Debugging Is Off/On. Off is quiet, On is verbose. This

chooses how detailed the error message reporting will be when communicating with an external device.

It is possible to connect the instrument to a computer through a parallel interface with a unique software driver. Because different computers vary widely in processing speed, the instrument must be able to adapt to differing data rates while communicating with those computers. With user-developed software drivers, the ability to obtain detailed error messages during the development can be very useful. For more information, contact your T ektronix Customer Service representatives. They have information describing the option port hardware and software protocol and custom development methods available.

1503C MTDR User Manual

1–9

Operating Instructions

The SP-232, a serial interface product, also allows for connection of the 1503C to other instrumentation, including computers, via the option port. SP-232 is an RS-232C-compatible interface. For more information, contact your Tektronix Customer Service Representative. They can provide you with additional details on the hardware and software protocol.

8. Display Contrast (Software Version 5.02 and above) a. Press the MENU button firmly once. If the display is very light or very dark,

you might not be able to see a change in the contrast.

b. T urn the VER TICAL SCALE knob slowly clockwise to darken the display

or counterclockwise to lighten the display . If you turn the knob far enough, the contrast will wrap from the darkest to lightest value.

c. When the screen is clearly readable, press the MENU button again to return

to normal measurement operation. The new contrast value will remain in effect until the instrument is turned off.

Test Preparations

The Importance of Vp

(Velocity of Propagation)

Vp of Various Dielectric

Types

Vp is the speed of a signal down the cable given as a percentage of the speed of light in free space. It is sometimes expressed as a whole number (e.g., 66) or a percentage (e.g., 66%). On the 1503C, it is the percentage expressed as a decimal number (e.g., 66% = .66). If you do not know the velocity of propagation, you can get a general idea from the following table, or use the Help with Cables section of the Cable Information menu. You can also find the Vp with the procedure that follows using a cable sample.

NOTE. If you do not know the Vp of your cable, it will not prevent you fr om finding a fault in your cable. However, if the Vp is set wrong, the distance readings will be affected.

All Vp settings should be set for the cable under test, not the supplied jumper cable.

Dielectric Probable Vp

Jelly Filled .64 Polyethylene (PIC, PE, or SPE) .66 PTFE (Teflon R) or TFE .70 Pulp Insulation .72 Foam or Cellular PE (FPE) .78 Semi-solid PE (SSPE) .84 Air (helical spacers) .98

1–10

1503C MTDR User Manual

Impedance of Various

Cable Types

Finding an Unknown Vp

Operating Instructions

50 W 75 W 93 W 125 W

RG-4 RG-6/U RG-7/U RG-23/U RG-8/U RG-11/U RG-22/U RG-63/U RG-9/U RG-12/U RG-62/U RG-79/U RG-58/U RG-13/U RG-71/U RG-89/U RG-62/U RG-59/U RG-111/U Flat Lead RG-81 RG-124/U Twisted Pair Twisted Pair RG-93 RG-140/U RG-142B/U RG-179/U RG-225/U 75  Video RG-303B/U RG-316/U RG-393/U Vertebrae Helix

1. Obtain a known length of cable of the exact type you wish to test. Attach the

cable to the CABLE connector on the front panel.

2. Pull POWER on.

3. Turn the DIST/DIV to an appropriate setting (e.g., if trying to find the Vp of a

three-foot cable, turn the DIST/DIV to 1 ft/div).

4. Turn the

POSITION control until the distance reading is the same as the

known length of this cable.

5. Turn the Vp controls until the cursor is resting on the rising portion of the

reflected pulse. The Vp controls of the instrument are now set to the Vp of the cable.

The following three illustrations show settings too low, too high, and correct for a sample three-foot cable.

ac 3.00 ft

O N

O F F

Figure 1–5: Vp Set at .30, Cursor Beyond Reflected Pulse (Setting Too Low)

1503C MTDR User Manual

1–11

Operating Instructions

ac 3.00 ft

O N

O F F

Figure 1–6: Vp Set at .99, Cursor Less Than Reflected Pulse (Setting Too High)

ac 3.00 ft

O N

O F F

Cable Test Procedure

Distance to the Fault

O F F

Figure 1–7: Vp Set at .66, Cursor on Rising Edge of Reflected Pulse (Set Correctly)

Be sure to read the previous paragraphs on Vp.

1. Set the 1503C controls:

POWER On CABLE Cable to BNC IMPEDANCE 50  NOISE FILTER 1 avg DIST/DIV (see below) Vp (per cable) PULSE WIDTH (per cable)

2. If you know approximately how long the cable is, set the DIST/DIV appropriately (e.g., 20-ft cable would occupy four divisions on the LCD if 5 ft/div was used). The entire cable should be displayed.

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Operating Instructions

ac 0.00 ft

O N

O F F

Figure 1–8: 20-ft Cable at 5 ft/div

If the cable length is unknown, set DIST/DIV to 5000 ft/div and continue to decrease the setting until the reflected pulse is visible. Depending on the cable length and the amount of pulse energy absorbed by the cable, it might be necessary to increase the VERT SCALE to provide more gain to see the reflected pulse.

The best pulse width is dependent on the cable length. A short pulse can be completely dissipated in a long cable. Increasing the pulse width will allow the reflected pulse to be more visible when testing long cables. AUTO will select the pulse width for you, depending on the distance on the right side of the LCD.

CABLE LENGTH

SUGGESTED PULSE SUGGESTED ft/div

0 to 100 ft 2 ns 10 ft/div 51 to 500 ft 10 ns 50 ft/div 501 to 5000 ft 100 ns 500 ft/div 5001 to 50,000 ft 1000 ns 5000 ft/div

When the entire cable is displayed, you can tell if there is an open or a short. Essentially, a drop in the pulse is a short and a rise in the pulse is an open. Less catastrophic faults can be seen as hills and valleys in the waveform. Bends and kinks, frays, water, and interweaving all have distinctive signatures.

ac 0.00 ft

O N

O F F

Short

O F F

Figure 1–9: Short in the Cable

1503C MTDR User Manual

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Operating Instructions

ac 20.00 ft

O N

O F F

Open

Figure 1–10: Open in the Cable

3. To find the distance to the fault or end of the cable, turn the

POSITION control until the cursor rests on the leading edge of the rising or falling reflected pulse (see Figure 1–10). Read the distance in the distance window in the upper right corner of the display.

A more thorough inspection might be required. This example uses a longer cable:

4. When inspecting a 455-foot cable, a setting of 100 ft/div allows a relatively fast

inspection. If needed, turn VERT SCALE to increase the gain. The higher the gain, the smaller the faults that can be detected. If noise increases, increase the NOISE FILTER setting.

ac 455.00 ft

O N

O F F

Figure 1–11: 455-ft Cable

5. Change DIST/DIV to 20 ft/div . The entire cable can now be inspected in detail

on the LCD. Turn the

POSITION control so the cursor travels to the far right side of the LCD. Keep turning and the cable will be “dragged” across the display.

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