Cable and antenna systems have a direct effect on wireless network performance.

A radio can be working properly, but the system may still perform poorly if the feed line, connectors, jumper cables or antenna path are damaged, mismatched or losing too much signal.

That is why field technicians use cable and antenna analyzers.

The source JM Test article explains that degradation or failure in the cable and antenna system can lead to poor voice quality, dropped calls and reduced base station performance. It also notes that field technicians use portable cable and antenna analyzers, such as Anritsu Site Master instruments, to analyse, troubleshoot, characterize and maintain the communication system.

For Canadian telecom, utility, public-safety, broadcast, mining, transportation, industrial and private radio networks, the practical question is simple:

Is the RF path healthy enough for the system to perform as expected?

Why Cable and Antenna Analysis Matters

The cable and antenna path is not always easy to replace.

A radio unit may be swapped quickly, but a tower feed line, rooftop coax run, antenna path, waveguide section or distributed antenna system may involve access planning, site safety, weather delays, tower crews, shutdown windows and customer approval.

That makes early troubleshooting important.

Cable and antenna analysis helps identify issues such as:

• Poor antenna match
• Excessive reflected power
• Loose connectors
• Corroded connectors
• Water ingress
• Damaged coaxial cable
• Dented or crushed feed line
• Faulty jumper cables
• Defective antennas
• Poor installation workmanship
• Incorrect frequency-band performance
• Excessive cable loss
• Damaged lightning arrestors
• Filter or duplexer issues
• System changes that affect RF performance

The source article identifies poorly installed connectors, dented or damaged coaxial cables and defective antennas as common failure trends in antenna systems.

What Measurements Are Used in Cable and Antenna Analysis?

The core measurements covered in the source article are:

• Return Loss
• VSWR
• Cable Loss
• Distance-to-Fault, or DTF

Part 1 focuses mainly on Return Loss, VSWR and Cable Loss. Part 2 continues into DTF and deeper interpretation.

Anritsu also describes common line sweep measurements for transmission feed line systems as including Return Loss, Cable Loss and DTF.

Each measurement answers a different question.

A complete RF troubleshooting process should not depend on only one trace.

Frequency Domain Reflectometry

Most modern cable and antenna analyzers use Frequency Domain Reflectometry, or FDR.

FDR uses swept RF frequencies to analyse the antenna and feed line system. The source article explains that this helps locate small changes and degradations at the system’s operating frequency, which can help prevent severe system failures.

This is one of the main reasons FDR is useful in real antenna systems.

It allows technicians to test the system at frequencies that matter to the actual network, instead of only checking the cable with a simple DC continuity test.

FDR-based testing can help identify:

• Reflections
• Mismatches
• Cable degradation
• Connector issues
• Frequency-dependent problems
• Filter and duplexer behaviour
• Changes compared with baseline traces
• Problems that simple continuity testing may miss

The source article also notes that RF sweeps can pass through frequency-selective devices such as filters, quarter-wave lightning arrestors and duplexers, which are common in cellular antenna systems.

Return Loss

Return Loss is one of the most important cable and antenna measurements.

It tells you how much signal is reflected back toward the source.

A well-matched antenna system reflects less energy.

A poorly matched antenna system reflects more energy.

The source JM Test article explains that Return Loss and VSWR show the match of the system and help determine whether it conforms to system engineering specifications. It also explains that a poorly matched antenna reflects RF energy that is no longer available for transmission and can affect transmitted power efficiency and coverage area.

Return Loss is expressed in dB.

In general:

• Higher Return Loss is better.
• Lower Return Loss is worse.
• 0 dB is very poor.
• A high dB value means less reflected power.

The source article gives a practical example: a 20 dB system Return Loss means about 1% of the power is returned and 99% is transmitted, while 10 dB Return Loss means about 10% of the power is returned. It also notes that acceptable limits vary by system, but 15 dB or better is a common system limit for cable and antenna systems.

Why Return Loss Matters

Return Loss matters because reflected RF energy does not help coverage.

If too much energy is reflected:

• Less power reaches the antenna.
• System efficiency drops.
• Coverage can be reduced.
• Transmitter performance may be affected.
• Site acceptance testing may fail.
• Faults may remain hidden until the system is under load.
• Customers may see poor voice quality, weak signal or dropped calls.

The source article connects poor antenna system performance with poor voice quality and dropped calls, and explains that reflected RF energy can distort the signal and affect transmitted power efficiency.

VSWR

VSWR stands for Voltage Standing Wave Ratio.

It is another way of expressing how well the system is matched.

Return Loss and VSWR both describe reflected energy, but they display it differently.

The source article explains that Return Loss displays the ratio of reflected power to reference power in dB, while VSWR displays the system match linearly by comparing voltage peaks and valleys.

In VSWR terms:

• 1:1 is an ideal match.
• A higher VSWR means worse match.
• Around 1.43:1 corresponds to about 15 dB Return Loss.
• Antenna manufacturers often specify match in VSWR.

The source article notes that a realistic match for a cable and antenna system may be around 1.43 VSWR, corresponding to 15 dB Return Loss.

Return Loss vs VSWR

Return Loss and VSWR show the same system behaviour in different formats.

Return Loss is usually easier to compare across a wide range because it uses a logarithmic dB scale.

VSWR is often familiar to antenna manufacturers and radio technicians because many antenna specifications use VSWR.

The source article explains that Return Loss is often preferred because logarithmic displays make it easier to compare small and large values, while VSWR shows the match linearly.

Return Loss to VSWR Conversion

The common conversion formulas are:

VSWR = (1 + 10^(-RL/20)) / (1 - 10^(-RL/20))

Return Loss = 20 log10((VSWR + 1) / (VSWR - 1))

The source article includes the Return Loss and VSWR relationship and gives an example where 8.84 dB Return Loss corresponds to about 2.15 VSWR.

Simple Return Loss / VSWR Reference

Use this table as a practical guide only. The acceptable limit depends on the system design, band, owner specification, carrier requirement and equipment manufacturer guidance.

Cable Loss

Cable Loss measures how much signal is lost as RF energy travels through the cable and connected components.

The source article explains that as a signal travels through the transmission path, some energy is dissipated in the cable and components. It also says Cable Loss measurement is commonly made during installation to confirm that cable loss is within manufacturer specification.

Cable Loss can come from:

• Cable length
• Cable type
• Cable diameter
• Operating frequency
• Connector loss
• Adapter loss
• Jumper loss
• Ageing cable
• Water ingress
• Corrosion
• Damage
• Poor installation
• Tight bends
• Crushed cable
• Frequency-selective components

Higher Cable Loss means less signal reaches the antenna or receiver.

Why Cable Loss Matters

Cable Loss affects both transmit and receive performance.

On transmit, Cable Loss reduces the power that reaches the antenna.

On receive, Cable Loss reduces the signal that reaches the receiver.

That can affect:

• Coverage
• Uplink and downlink performance
• Link margin
• Receiver sensitivity at the system level
• Data throughput
• Voice quality
• Dropped calls
• Public-safety radio reliability
• Microwave link reliability
• Site acceptance testing
• Troubleshooting accuracy

The source article explains that increasing RF frequency and cable length increases insertion loss, and that larger-diameter cables generally have less insertion loss and better power-handling capability than smaller-diameter cables.

How Cable Loss Is Measured

Cable Loss can be measured using different methods.

The source article notes that Cable Loss can be measured with a portable vector or scalar network analyzer, a power meter, or through the Return Loss measurement available in a cable and antenna analyzer. It explains that by placing a short at the end of the cable, the signal is reflected back and the energy lost in the cable can be computed.

A practical Cable Loss setup may include:

1. Disconnect the antenna or load according to the approved procedure.
2. Inspect and clean connectors.
3. Connect a phase-stable test port cable.
4. Calibrate the analyzer at the correct reference plane.
5. Connect the short or required termination at the far end.
6. Sweep across the required frequency range.
7. Read the average Cable Loss.
8. Save the trace and test setup notes.
9. Compare the result to manufacturer specifications, design limits or previous baseline data.

Many modern cable and antenna analyzers include a Cable Loss mode that calculates average loss automatically. The source article says this is usually preferred because it removes the need for manual math.

Cable Loss Mode vs Return Loss Mode

The source article explains that average cable loss can be estimated by adding the peak and valley of the trace and dividing by two in Cable Loss mode, or by four in Return Loss mode to account for the signal travelling out and back.

This matters because a reflected measurement includes a two-way trip:

• The signal travels down the cable.
• It reflects at the far end.
• It travels back through the cable.

That means the measured loss can include the cable path twice.

Modern analyzers simplify this by displaying Cable Loss directly.

Still, technicians should understand what the instrument is doing so they do not misread the trace.

Frequency Matters

Cable Loss is not fixed across all frequencies.

The same cable will usually have more loss at higher frequencies.

The source article explains that increasing RF frequency increases insertion loss.

This matters for systems such as:

• VHF
• UHF
• 700 MHz public safety
• 800 MHz radio systems
• Cellular systems
• LTE
• 5G
• Microwave links
• Distributed antenna systems
• Utility SCADA radio
• Private wireless systems

A cable path that looks acceptable at one frequency may not be acceptable at another.

Always test across the operating band that matters for the system.

Cable Diameter Matters

Cable diameter also affects loss.

The source article notes that larger-diameter cables usually have less insertion loss and better power handling than smaller-diameter cables.

In practical terms:

• A short jumper may be acceptable with smaller cable.
• A long tower feed line may need lower-loss cable.
• Higher-power systems may need cable with better power handling.
• Higher-frequency systems may need lower-loss design.
• Old or damaged cable may no longer meet the original specification.

Cable selection should match the system design, frequency, power, distance and environmental exposure.

Return Loss and Cable Loss Should Be Interpreted Together

Return Loss tells you about match.

Cable Loss tells you how much energy is lost in the path.

Both matter.

A system can fail because:

• The antenna is mismatched.
• The cable has too much loss.
• The connectors are poor.
• The feed line is damaged.
• The antenna and cable are both contributing to the issue.
• Cable loss is masking another problem.

Part 2 of the original JM Test series goes deeper into how cable loss can make system Return Loss look better than the antenna actually is. For Part 1, the key point is that Return Loss and Cable Loss should not be treated as the same measurement.

Use both when the system performance does not match expectations.

Distance-to-Fault Overview

Although Part 1 only introduces the core fundamentals, DTF is part of the overall cable and antenna analysis workflow.

DTF helps locate where a fault or reflection occurs along the transmission line.

Anritsu describes Site Master, Cell Master and VNA Master handheld products as tools that measure DTF, Return Loss and VSWR on coax and waveguide transmission lines.

DTF is useful when Return Loss, VSWR or Cable Loss results suggest a problem.

It can help locate:

• Bad connectors
• Damaged cable sections
• Water ingress
• Cable kinks
• Crushed cable
• Poor jumpers
• Open or shorted ends
• Discontinuities
• Faults near antennas or equipment rooms

Return Loss and VSWR tell you whether the system match is acceptable.

DTF helps find where the fault may be.

Typical Cable and Antenna Analyzer Workflow

A practical field workflow may look like this:

1. Confirm the site, system and frequency band.
2. Review previous baseline traces.
3. Inspect the cable path and connectors.
4. Confirm the correct analyzer model and frequency range.
5. Confirm calibration kit, adapters and test port cable.
6. Calibrate the analyzer at the correct reference plane.
7. Measure Return Loss or VSWR.
8. Measure Cable Loss where needed.
9. Run DTF if the system fails or if fault location is needed.
10. Save all traces.
11. Record test setup notes.
12. Compare against specification and historical results.
13. Repair or escalate based on findings.
14. Retest after correction.

The source article emphasizes that cable and antenna analyzers are used to analyse, troubleshoot, characterize and maintain the communication system.

What Problems These Tests Can Find

Cable and antenna analysis can help uncover:

Poorly Installed Connectors

Loose, poorly torqued, contaminated or incorrectly installed connectors can create reflections and loss.

Dented or Damaged Coaxial Cable

Physical cable damage can change impedance and increase loss.

Defective Antennas

An antenna that is not matched properly can reflect RF energy back toward the source.

Water Ingress

Moisture can change cable characteristics and increase loss or reflections.

Wrong Cable or Jumper

A cable that is too lossy for the band or distance can reduce performance even if it is not physically damaged.

Frequency-Dependent Failures

Some problems appear only in certain bands, which is why sweeping the correct operating frequency matters.

The source article specifically identifies poorly installed connectors, dented or damaged coaxial cables and defective antennas as common antenna-system failure trends.

Canadian RF and Antenna System Context

Cable and antenna analysis is mainly a performance and troubleshooting activity.

But RF systems also exist inside a Canadian regulatory and safety environment.

Health Canada’s Safety Code 6 sets recommended safety limits for human exposure to radiofrequency electromagnetic fields in the frequency range from 3 kHz to 300 GHz.

Health Canada explains that ISED regulates wireless communication equipment, including cell towers, and oversees licensing and placement of cell phone towers while ensuring compliance with regulatory standards for human exposure limits under Safety Code 6.

A cable and antenna analyzer does not prove Safety Code 6 compliance by itself.

It helps troubleshoot RF path performance.

RF exposure compliance requires the correct site information, access controls, calculations, survey methods and regulatory process.

Canadian Field Safety Considerations

Cable and antenna analysis can involve more than an analyzer and a cable.

Testing may happen on:

• Towers
• Rooftops
• Industrial sites
• Mines
• Utilities
• Rail corridors
• Ports
• Remote sites
• Public-safety communication sites
• Data centres
• Telecommunication shelters
• Broadcast facilities

Before testing, confirm:

• Site access authorization
• RF exposure controls
• Whether transmitters must be shut down
• Lockout or transmitter control procedure
• Rooftop or tower fall protection
• Weather conditions
• Lightning risk
• Electrical hazards
• Working alone rules
• Public access control
• Antenna sector awareness
• Cable and connector handling procedure
• Required PPE
• Customer or carrier requirements

Do not treat RF testing as low risk only because the instrument is handheld.

The environment and active RF sources may be the real hazard.

What to Document in a Cable and Antenna Test Report

Good documentation makes future troubleshooting easier.

A useful report may include:

• Site name
• Location
• System name
• Sector or antenna ID
• Cable ID
• Test date
• Technician
• Analyzer model
• Analyzer serial number
• Calibration status
• Calibration kit used
• Test port cable used
• Connector adapters used
• Frequency range
• Measurement type
• Return Loss trace
• VSWR trace where required
• Cable Loss trace
• DTF trace where required
• Cable type
• Cable length where known
• Pass/fail criteria
• Limit lines
• Setup notes
• Weather or site notes
• Repairs made
• Before-and-after traces

Baseline traces are especially useful.

A cable and antenna system may not fail suddenly. It may degrade gradually. Saved traces help show whether a connector, cable or antenna path has changed over time.

Choosing the Right Cable and Antenna Analyzer

Before renting or buying a cable and antenna analyzer, confirm:

• Required frequency range
• Return Loss / VSWR requirement
• Cable Loss requirement
• DTF requirement
• Coaxial or waveguide path
• Connector types
• Calibration kit type
• Test port cable
• Required adapters
• Power meter requirement
• Spectrum analysis requirement
• PIM testing requirement
• Reporting software
• Data storage
• Battery runtime
• Current calibration certificate
• Rental duration
• Canadian availability

The source article references Anritsu Site Master S331E and S332E analyzers as examples of portable tools used by field technicians for cable and antenna system work.

JM Test Canada’s calibration services page lists RF and microwave capabilities including microwave Site Masters, PIM testers, signal sources, network analyzers, power meters, attenuators, waveguide calibration kits and cable and antenna analyzers / RF sweep gear.

Rental and Calibration Support

Cable and antenna analyzers are often needed for specific projects, site acceptance work, emergency troubleshooting or maintenance windows.

Rental can make sense when:

• The instrument is needed for one project.
• The required frequency range is unusual.
• A calibrated unit is needed quickly.
• A contractor needs extra analyzers for a rollout.
• A site failure needs urgent troubleshooting.
• The owned unit is out for calibration.
• A specific Site Master model or accessory kit is needed.

JM Test Canada’s rental page states that its rental division includes instrument and controls, electrical, communications, gas detection, utility and mechanical equipment. It also says rentals include applicable accessories and current calibration documentation.

For the Canadian page, keep exact model availability conditional.

Customers should confirm:

• Cable and antenna analyzer availability
• Site Master model
• Frequency range
• Calibration kit
• Test port cable
• Connector adapters
• Load / short / open kit
• Current calibration certificate
• Reporting software
• Rental term
• Shipping timeline
• Canadian service location

Common Cable and Antenna Analysis Mistakes

Treating Return Loss and Cable Loss as the Same Measurement

Return Loss measures reflected energy. Cable Loss measures signal lost through the transmission path.

Testing the Wrong Frequency Range

The system must be tested across the operating frequency band that matters.

Using the Wrong Adapters

Every adapter adds uncertainty and can introduce mismatch. Use the correct connector type and minimize unnecessary adapters.

Skipping Calibration

Field measurements depend on the correct calibration setup and reference plane.

Ignoring Cable Diameter and Length

Longer cable and higher frequency usually increase insertion loss. Larger-diameter cables generally have lower insertion loss than smaller-diameter cables.

Assuming a Good VSWR Means the Whole System Is Healthy

VSWR is important, but it does not tell the whole story. Cable Loss and DTF may still be needed.

Not Saving Baseline Traces

Future troubleshooting is much harder without previous trace data.

Renting the Analyzer Without Accessories

The analyzer is only one part of the kit. The calibration kit, test port cable, adapters and terminations are just as important.

Practical Takeaway

Cable and antenna analysis helps field technicians understand whether the RF path is performing correctly.

Return Loss and VSWR show how well the antenna system is matched.

Cable Loss shows how much signal is being lost through the transmission path.

DTF helps locate faults when deeper troubleshooting is needed.

The source JM Test article explains that cable and antenna analyzers are used to analyse, troubleshoot, characterize and maintain communication systems, and that Return Loss, Cable Loss and DTF are fundamental cable and antenna measurements.

For Canadian telecom, public-safety, utility, broadcast and industrial communication systems, the best approach is to:

• Test at the correct operating frequency.
• Use the correct analyzer and accessories.
• Calibrate at the correct reference plane.
• Measure Return Loss or VSWR.
• Measure Cable Loss where needed.
• Use DTF when fault location is required.
• Save traces for documentation and future comparison.
• Confirm Canadian RF exposure and site safety requirements separately from RF path testing.

JM Test Systems Canada can support RF and communications test-equipment needs where available, including rental and calibration support for communications test equipment and RF / microwave tools. Confirm exact model, frequency range, accessories, calibration certificate and Canadian availability before booking.