https://urgentcomm.com/wp-content/themes/ucm_child/assets/images/logo/footer-logo.png
  • Home
  • News
  • Multimedia
    • Back
    • Multimedia
    • Video
    • Podcasts
    • Galleries
  • Commentary
    • Back
    • Commentary
    • Urgent Matters
    • View From The Top
    • All Things IWCE
    • Legal Matters
  • Resources
    • Back
    • Resources
    • Events
    • Webinars
    • White Papers
    • Reprints & Reuse
  • IWCE
    • Back
    • IWCE
    • Conference
    • Special Events
    • Exhibitor Listings
    • Premier Partners
    • Floor Plan
    • Exhibiting Information
    • Register for IWCE
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Terms of Service
    • Privacy Statement
    • Cookies Policy
  • Related Sites
    • Back
    • American City & County
    • IWCE
    • Light Reading
    • IOT World Today
    • Mission Critical Technologies
    • Microwave/RF
    • T&D World
    • TU-Auto
  • In the field
    • Back
    • In the field
    • Broadband Push-to-X
    • Internet of Things
    • Project 25
    • Public-Safety Broadband/FirstNet
    • Virtual/Augmented Reality
    • Land Mobile Radio
    • Long Term Evolution (LTE)
    • Applications
    • Drones/Robots
    • IoT/Smart X
    • Software
    • Subscriber Devices
    • Video
  • Call Center/Command
    • Back
    • Call Center/Command
    • Artificial Intelligence
    • NG911
    • Alerting Systems
    • Analytics
    • Dispatch/Call-taking
    • Incident Command/Situational Awareness
    • Tracking, Monitoring & Control
  • Network Tech
    • Back
    • Network Tech
    • Interoperability
    • LMR 100
    • LMR 200
    • Backhaul
    • Deployables
    • Power
    • Tower & Site
    • Wireless Networks
    • Coverage/Interference
    • Security
    • System Design
    • System Installation
    • System Operation
    • Test & Measurement
  • Operations
    • Back
    • Operations
    • Critical Infrastructure
    • Enterprise
    • Federal Government/Military
    • Public Safety
    • State & Local Government
    • Training
  • Regulations
    • Back
    • Regulations
    • Narrowbanding
    • T-Band
    • Rebanding
    • TV White Spaces
    • None
    • Funding
    • Policy
    • Regional Coordination
    • Standards
  • Organizations
    • Back
    • Organizations
    • AASHTO
    • APCO
    • DHS
    • DMR Association
    • ETA
    • EWA
    • FCC
    • IWCE
    • NASEMSO
    • NATE
    • NXDN Forum
    • NENA
    • NIST/PSCR
    • NPSTC
    • NTIA/FirstNet
    • P25 TIG
    • TETRA + CCA
    • UTC
Urgent Communications
  • NEWSLETTER
  • Home
  • News
  • Multimedia
    • Back
    • Video
    • Podcasts
    • Galleries
  • Commentary
    • Back
    • All Things IWCE
    • Urgent Matters
    • View From The Top
    • Legal Matters
  • Resources
    • Back
    • Events
    • Webinars
    • White Papers
    • Reprints & Reuse
    • UC eZines
  • IWCE
    • Back
    • Conference
    • WHY ATTEND
    • Exhibitor Listings
    • Floor Plan
    • Exhibiting Information
    • Registration Opens April 2019-Join Our Mailing List
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Terms of Service
    • Privacy Statement
    • Cookies Policy
  • Related Sites
    • Back
    • American City & County
    • IWCE
    • Light Reading
    • IOT World Today
    • TU-Auto
  • newsletter
  • In the field
    • Back
    • Internet of Things
    • Broadband Push-to-X
    • Project 25
    • Public-Safety Broadband/FirstNet
    • Virtual/Augmented Reality
    • Land Mobile Radio
    • Long Term Evolution (LTE)
    • Applications
    • Drones/Robots
    • IoT/Smart X
    • Software
    • Subscriber Devices
    • Video
  • Call Center/Command
    • Back
    • Artificial Intelligence
    • NG911
    • Alerting Systems
    • Analytics
    • Dispatch/Call-taking
    • Incident Command/Situational Awareness
    • Tracking, Monitoring & Control
  • Network Tech
    • Back
    • Cybersecurity
    • Interoperability
    • LMR 100
    • LMR 200
    • Backhaul
    • Deployables
    • Power
    • Tower & Site
    • Wireless Networks
    • Coverage/Interference
    • Security
    • System Design
    • System Installation
    • System Operation
    • Test & Measurement
  • Operations
    • Back
    • Critical Infrastructure
    • Enterprise
    • Federal Government/Military
    • Public Safety
    • State & Local Government
    • Training
  • Regulations
    • Back
    • Narrowbanding
    • T-Band
    • Rebanding
    • TV White Spaces
    • None
    • Funding
    • Policy
    • Regional Coordination
    • Standards
  • Organizations
    • Back
    • AASHTO
    • APCO
    • DHS
    • DMR Association
    • ETA
    • EWA
    • FCC
    • IWCE
    • NASEMSO
    • NATE
    • NXDN Forum
    • NENA
    • NIST/PSCR
    • NPSTC
    • NTIA/FirstNet
    • P25 TIG
    • TETRA + CCA
    • UTC
acc.com

content


Technically speaking: Troubleshooting techniques 101

Technically speaking: Troubleshooting techniques 101

Over the years the requirements of a land mobile radio technician have changed considerably. In spite of all the changes, one thing still separates the
  • Written by Urgent Communications Administrator
  • 1st September 1996

Over the years the requirements of a land mobile radio technician have changed considerably. In spite of all the changes, one thing still separates the “men from the boys”–the troubleshooting ability of the technician, not age or experience. Of course, age and experience certainly tend to enhance the ability of the seasoned technician, but one must have the potential to begin.

You have probably seen “technicians” come and go who could never seem to properly diagnose problems effectively. The “hunt and miss” techniques they used just didn’t cut it in the busy land mobile radio shop where turning out work on a timely basis is survival.

There is no single “right” way to troubleshoot a given piece of communication equipment. Two technicians, given the same arsenal of test equipment, may proceed differently in troubleshooting the same problem. The best method would be the one that leads to the fastest repair of the malfunctioning equipment. In this series we will look at some of the proven methods of troubleshooting that have evolved over the years, and some of the unorthodox methods as well.

The workbench To troubleshoot efficiently, the workbench must be properly organized and equipped. The workbench should have all the test equipment that is commonly used in troubleshooting land mobile equipment. The equipment should be within easy reach from the technician’s normal working position. The center piece of the equipment arsenal is the service monitor. The service monitor normally contains virtually all of the basic test equipment requirements in an integrated package for convenience and accessibility. Other test equipment should include a high-quality bench power supply with voltage and current metering, including adjustable foldback-current-limiting to protect both the supply and the equipment under test.

The workbench should provide sufficient space to place the service manual without taking up all the needed work space. The workbench should be kept uncluttered and should be cleaned between each service job. A cluttered workbench leads to confusion, resulting in inefficiency and, thus, longer service time. A complete set of interconnecting test cables should be nearby and kept in good repair. A bad or intermittent test cable can send the best technician on an occasional wild goose chase!

Of course, good lighting is a must. In addition, a lighted magnifier should be attached to the workbench. The age of microminiaturization necessitates this. Sometimes, a fluorescent light fixture can generate lots of noise, which may interfere with receiver sensitivity tests. Still, fluorescent lighting is desired–just make sure the lighting isn’t causing noise to appear in the receiver.

Talk to the customer The way a customer describes a problem may be confusing, and the technician should make an effort to confirm weird complaints. Remember, the customer is not familiar with technical terms and may describe a problem in an unusual manner. Quiz the customer until you gain an understanding of the problem. It may be a case of the customer not operating the equipment properly.

The equipment should be removed to the workbench only when it is determined that the problem does not lie in the installation or improper operation. Once the equipment is on the workbench, all complaints should be verified through external test and measurement procedures.

Confirming the symptoms When faced with a malfunctioning piece of equipment, often the most difficult part of troubleshooting is deciding where to begin. Let the symptoms be your guide.

Suppose you are handed a transceiver, and you are told that the receiver is inoperative. That complaint is not definitive and, therefore, will require some “external” tests to provide a more definitive answer as to what type of problem exists within the receiver.

The logical step is to hook up the transceiver on the test bench and test the controls, such as squelch and volume. Also, when using the ammeter on the bench power supply, check to make sure the transceiver is drawing the proper amount of current. A large current drain in the receive standby mode would indicate a probable short circuit in the transceiver.

Run a sensitivity check on the receiver. Use both the SINAD and the 20dB-quieting method, and compare results with receiver specifications. If the sensitivity is poor with both methods, then one or more stages of the receiver apparently are malfunctioning.

If you cannot force a high-level signal through the receiver, it is likely that one of the local oscillators (first or second) is not working (assuming the audio section is working). Usually, unless a local oscillator is dead, you will be able to force a high-level (1,000 microvolts or greater) signal through the receiver. It may not sound good, but you should be able to hear it in the speaker.

Operation of the local oscillator(s) can be determined through the use of a spectrum analyzer with a “sniffer” probe held near the oscillator or mixer. In synthesized receivers, the local oscillator will be a voltage-controlled oscillator (VCO). Some sets are single-conversion–there will be no second oscillator. Crystal oscillator failure is most often caused by a defective crystal. In synthesized sets, if the synthesizer is “out of lock,” the entire transceiver usually is disabled by the lock detector. An out-of-lock condition can be caused by a variety of problems within the synthesizer–missing reference oscillator, missing VCO signal, alignment problems, programmable divider problems and a host of other ills.

To find the defective component(s), troubleshooting must follow some systematic procedure. Generally speaking, the trouble must be localized to a section. Once the defective section is determined, the trouble is next localized to a stage. Then within the stage, the trouble must be localized to the defective component(s). Again, the method used to implement this process may vary from technician to technician; however, there are some general rules that can apply.

Next time we will examine several techniques for signal tracing and signal injection that are used to troubleshoot typical land mobile radio communications gear. We will look at some short cuts that can lead you to a dead or seriously impaired stage quickly.

So, until next time–stay tuned!

Tags: content

Related


  • RugGear: Contributing to the future of mission-critical broadband communication review and market vision
    As one of the leading international developers and manufacturers of rugged mobile phones, smartphones and tablets for professional use in extreme safety and working conditions RugGear is becoming an increasingly important player in the field of mission critical communications. With our high-performance mission critical flagship product RG760 we are proud to contribute to the future […]
  • Photo gallery: 2014 Communications Marketing Conference (CMC) in Tucson
    This photo gallery features scenes from the 2014 Communications Marketing Conference (CMC) in Tucson, Ariz.
  • Top 5 Stories - Week of Sept. 22
    Top 5 Stories - Week of Sept. 22
    Here’s a look at the most popular stories on IWCE’s Urgent Communications from the last week.
  • RCA plans to expand this year's Technical Symposium
    RCA plans to expand this year's Technical Symposium
    Recent presentations, given by both startups and major corporations, have included fractal antennas, LTE, emergency communications, "invisibility cloaks" using RF, disabling IEDs with RF and tropospheric ducting.

Leave a comment Cancel reply

To leave a comment login with your Urgent Comms account:

Log in with your Urgent Comms account

Or alternatively provide your name, email address below:

Your email address will not be published. Required fields are marked *

Related Content

  • Newscan: Indiana 911 dispatch-center deadline looms
  • Newscan: Texting 911 becomes an option for some Pennylvania cell-phone users
  • Newscan: Senator wants inventory of government spectrum
  • CMA conducts 40th conference this week

Commentary


Unlocking the power of ESInets: Different NG911 provisioning approaches exist; level of control is key differentiator

7th April 2021

Ransomware? Let’s call it what it really is: extortionware

21st February 2021

Redefining communications for today’s mobile workforces

18th February 2021
view all

Events


UC Ezines


IWCE 2019 Wrap Up

13th May 2019
view all

Twitter


UrgentComm

Newscan: Single sign-in for government services expands to states, localities dlvr.it/RxLQNR

9th April 2021
UrgentComm

‘Life-saving technology’: AST SpaceMobile CEO outlines capabilities of direct-to-smartphone LEO satellite service dlvr.it/RxKqvp

9th April 2021
UrgentComm

Handcuffs over AI: Solving security challenges with law enforcement dlvr.it/RxGtpD

8th April 2021
UrgentComm

Fujistsu: Cyber cretins are casing out private 5G dlvr.it/RxGnfN

8th April 2021
UrgentComm

Faster in-vehicle Wi-Fi dependent on faster connectivity dlvr.it/RxGnZL

8th April 2021
UrgentComm

Digital-health infrastructure benefits from cloud-to-edge architecture dlvr.it/RxFcjx

8th April 2021
UrgentComm

All actions monitored: The 10 most surveilled major cities in the U.S. dlvr.it/RxFZHV

8th April 2021
UrgentComm

Unlocking the power of ESInets: Different NG911 provisioning approaches exist; level of control is key differentiat… twitter.com/i/web/status/1…

7th April 2021

Newsletter

Sign up for UrgentComm’s newsletters to receive regular news and information updates about Communications and Technology.

Expert Commentary

Learn from experts about the latest technology in automation, machine-learning, big data and cybersecurity.

Business Media

Find the latest videos and media from the market leaders.

Media Kit and Advertising

Want to reach our digital and print audiences? Learn more here.

DISCOVER MORE FROM INFORMA TECH

  • American City & County
  • IWCE
  • Light Reading
  • IOT World Today
  • Mission Critical Technologies
  • Microwave/RF
  • T&D World
  • TU-Auto

WORKING WITH US

  • About Us
  • Contact Us
  • Events
  • Careers

FOLLOW Urgent Comms ON SOCIAL

  • Privacy
  • CCPA: “Do Not Sell My Data”
  • Cookies Policy
  • Terms
Copyright © 2021 Informa PLC. Informa PLC is registered in England and Wales with company number 8860726 whose registered and Head office is 5 Howick Place, London, SW1P 1WG.
This website uses cookies, including third party ones, to allow for analysis of how people use our website in order to improve your experience and our services. By continuing to use our website, you agree to the use of such cookies. Click here for more information on our Cookie Policy and Privacy Policy.
X