Vectronics SWR-584C User Manual

SWR-584C

HF/VHF/220MHz SWR Analyzer

Owner's Manual

CAUTION: Read All Instructions Before Operating Equipment !

300 Industrial Park Road

Starkville, MS 39759

(662) 323-5800

VERSION A2

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

1.0 Introduction

The SWR-584C is a compact battery-powered RF-impedance analyzer that covers 0.53-230 MHz in nine overlapping bands. Fully portable and self contained, it delivers a wide range of basic and advanced RF measurements to present a complete picture of your antenna systems and networks. It also measures capacitance, inductance, and serves as a discrete signal generator and frequency counter for the test bench. The SWR-584C is the latest entry in a long line of time-tested designs using proven technology and rugged construction to ensure years of reliable service. Please read through this manual carefully before powering up your

analyzer for the first time. The manual contains important safety information you'll need to

know to avoid damaging your unit. There's also valuable operating instruction to help you to take advantage of its full range of functions and features right away.

1.1 SWR-584C Control Layout

VECTRONICS

MFJ

POWER

11-28

Lower Range

0.53-1.0

GATE

MODE

GROUND

POST

ANTENNA

FREQUENCY

COUNTER

INPUT

POWER

13.8 VDC

MFJ HF/VHF SWR ANALYZER

HF/VHF/220MHz SWR Analyzer

SWR-584C

MODEL MFJ-259C

SWR

TUNE

IMPEDANCE

FREQUENCY MHz

67-113 28-67

113-155

155-230

2.1-4.7 1.0-2.1

4.7-11

1. Antenna Port: SO-239 for attaching antennas and RF devices under test.

2. Ground Post: Binding post for attaching leads to chassis ground.

3. Counter Input: BNC-female input jack for analyzer's Frequency Counter function.

4. External Power: 2.1-mm power jack accepts power adapter or supply (13.8V + center pin).

5. Power Switch: Applies power from internal batteries or external power source.

6. LCD Display: Two-line digital display presents operating frequency and measured data.

7. SWR Meter: Provides continuous analog readout of SWR measurements (Zo=50).

8. Impedance Meter: Displays impedance magnitude or reactance measurements.

9. Gate: Push button sets counter gate speed, performs other specified functions.

10. Mode: Push button selects measurement mode, performs other specified functions.

11. Tune: VFO capacitor, provides analog frequency control for the analyzer's generator.

12. Frequency: High and low-range band switches select analyzer's operating range.

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

1.2 Analyzer Measurement Functions

• SWR: LCD display and analog meter, Zo = 50Ω or Zo programmable

• Complex Impedance: Resistive and Reactive components (R ±jX)

• Vector Impedance: Z-magnitude plus Phase Angle

• Impedance (Z): Analog meter display, Zo=50 Ω

• Return Loss: Digital display, in dB

• Inductance (uH), Reactance (XL): Digital display with frequency

• Capacitance (pF), Reactance (Xc): Digital display with frequency

• Resonance: Digital and analog reactance null (X=0) with frequency

• Electrical Length: Digital, measured in feet.

• Feedline Loss: Digital, measured in dB

• Signal Frequency: Discrete counter function with three gate speeds

• Signal Generation: 20-mW (3-Vpp) output into 50 Ω, > -25 dBc suppression.

1.3 Theory of Operation: The SWR-584C has four basic electronic elements. (1.) A tunable

VFO with counter readout that generates RF signals to energize the load or device under test (DUT). (2.) A Directional Coupler (or bridge) to measure RF incident and reflected voltages sent to the load. (3.) A Central Processor that reads bridge voltages and processes them into usable data. (4.) A LCD Display and two analog meters that present all computed data visually.

The processor also performs other mathematical calculations and conversions.

Ant Jack

Bridge

Load (DUT)

LCD

Display

Tune

VFO

A/D Converter and Processor

Meters

The SWR-584C will serve as your eyes and ears when working with RF systems. However, all handheld analyzers share certain limitations, and being aware of them will help you to achieve more meaningful results.

1.4 Local Interference

: Like most hand-held designs, the SWR-584C uses a broadband

directional coupler that is open to incoming signals across the radio spectrum. Most of the time, the unit's built in +5-dBm RF generator is powerful enough to override any interference caused by stray pickup. However, under some circumstances, a powerful nearby transmitter could inject enough RF energy through the antenna being tested to overload the coupler and disrupt readings. If overload occurs, measurements may become erratic or SWR readings inaccurately high. These occurrences are rare, but if it becomes a problem at your particular

testing location, the MFJ-731 Tunable Analyzer Filter is especially designed to notch out

unwanted signals with minimal impact on analyzer accuracy.

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

1.5 Calibration Plane: Your analyzer's Calibration Plane is the point of reference where all measurements have greatest accuracy (Gain Reference = 0dB and Phase Shift = 0 degrees). For basic handheld units like the SWR-584C, the calibration plane is always fixed at the analyzer's RF connector. Any time a transmission line is installed between the analyzer's RF

connector and an item being tested, the cable will displace the load from the calibration plane and introduce some form of measurement transformation.

For SWR measurement, installing lengths of feedline usually causes a slight reduction in readings caused by attenuation losses. Unless the cable losses are high, the difference is usually insignificant. However, when documenting the performance of a new antenna design or network device, the analyzer should always be connected as close to the load as possible to minimize padding down of SWR readings.

Displacement of the calibration plane becomes far more significant when measuring impedance because of phase rotation and transformer action occurring in the feedline. In fact, impedance readings may swing dramatically, depending on the cable's electrical length and the severity of the load's mismatch referenced to 50 Ohms. To collect meaningful impedance

data for a device, always connect the analyzer directly -- using the shortest cable possible.

1.6 Reactance Sign Ambiguity: Most handheld analyzers, including the SWR-584C, lack

the data processing capability required to calculate Reactance Sign. These signs are (+) for

inductive reactance XL and (-) for capacitive reactance Xc. In most cases, you can apply one or more simple tests to determine sign. See specific measurement instructions for details.

1.7 Protecting Your Analyzer: To minimize measurement error at high frequencies, the

analyzer's detector diodes are installed directly at the antenna port. Be aware that applying any external potential exceeding a few volts of RF, AC, DC, or ESD energy could cause damage.

Caution and common sense are the best protections against failure. Never connect a transmitter to the Antenna jack, and when testing ungrounded antenna systems that could accumulate a static charge, always short the connector before attaching it to the analyzer.

Short Antenna

Leads to Discharge

Static Before

Connecting!

Important Warning: Never applying an external voltage to the Antenna jack -- it could damage sensitive detector diodes. Also, always discharge the coax connector to bleed off static before attaching ungrounded arrays.

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

2.0 Power Management

Read this section carefully -- supplying the wrong external voltage or failing to follow battery installation procedures could result in permanent damage!

2.1 External Power Requirements: The MFJ-1312D AC adapter meets all technical

requirements for powering the analyzer and it is recommended. Any other external power source must meet the following specifications:

• Current: 250 mA or greater

• Voltage Range: 11-16 VDC, well filtered (14 VDC ideal)

• Battery Charging: 13.8 VDC minimum required for battery charger operation

• Polarity: Negative ground only

• Connection: 2.1-mm (+) center pin, (-) chassis ground (see below)

2.2 Internal Battery Power: Always install fresh cells with identical part numbers and

expiration dates. For non-rechargeable power, install premium Alkaline cells and remove weak

cells immediately to prevent leakage. For rechargeable power, NiCds work well but Ni-MH cells

have no charge memory, hold a charge longer, and offer greater storage capacity. Before

loading new cells, always check (or know) the charger operating status -- is it On or Off ?

Important Warning: You must disable the analyzer's charger circuit when using nonrechargeable batteries, or destructive cell damage and chemical leakage may result.

2.3 Setting The Charger: Remove the analyzer's back cover (4 screws on each side of the case). Find the upper left-hand corner of the main pc board and locate the 3-pin header J5 next to the power jack. A small black shorting plug is installed on the header.

Charger Off (non-rechargeable cells), install header on center and right pins as shown:

2.1 mm

Charger On (rechargeable cells), install header on center and left pins as shown:

The charger provides a near-constant 20-mA/hr "trickle" rate any time external power is applied. The Power switch need not be on for charging to take place. Charging depleted cells may require 12 hours or more, so always allow enough time. Batteries will not over-charge.

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

Important Warning: Never store your unit more than a month with batteries installed. Also, never ship with batteries installed or swap cells with the power switch "On"!

2.4 Low Voltage Alert

: If the batteries (or external DC supply) drops below 11 Volts, a

flashing warning will appear on-screen (see below):

Voltage Low 10.5

Tapping the Mode button one time disables the warning and allows you to continue testing, but measurements made at low voltage may not be reliable. If possible, plug in an external power

source or discontinue testing until batteries are replaced or recharged.

2.5 Sleep Mode (Standby): The SWR-584C normally draws around 220 mA, consumed mostly by the stimulus generator's amplifier stages. To extend battery life, your unit features a built-in standby function called Sleep Mode. Sleep Mode shuts down signal generation and reduces current drain to under 15 mA during periods of analyzer inactivity.

The analyzer's processor monitors activity by sensing activation of the Mode switch and by looking for any change in the Tune control greater than 50 kHz. If neither event occurs during

a three-minute interval, the processor registers "inactivity" and switches into standby or Sleep

mode. A blinking SLP message on the display signals shutdown (see below):

10.125 MHz 1.3 R=42 X=12 SLP

2.6 Wake Up (Cancel SLP): To pull the unit out of SLP (standby), momentarily press either the Mode or Gate button and resume normal operation.

2.6 Disable SLP: You may disable the SLP function manually if it interrupts your work. To disable it, turn the analyzer Off, then turn it On again while holding down the Mode button. Continue holding Mode until the copyright message appears on the screen, then release it. When SLP is defeated, the message shown below will appear:

Power Saving Off

Note that SLP is a default function in the SWR-584C -- it resets automatically each time you power up unless you hold down the Mode key to defeat it. To restore the SLP function at any

time during an ongoing test session, simply turn the analyzer Off and then reboot it On again.

2.7 Powering-up (Boot) Sequence

: To turn the analyzer On, press Power. Three boot

screens appear in sequence before the analyzer enters it's default SWR R&X measurement

mode. The first two screens show the analyzer's software version and copyright date (important information when seeking technical assistance from VECTRONICS):

SWR-584C Ver X.XX

VECTRONICS

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

(

The third screen provides a voltage check -- and flashes a warning if voltage is too low:

Voltage Low 10.5 Voltage OK 14.2

The fourth screen shows the operating frequency plus SWR and R&X impedance data. This is

the analyzer's default measurement mode. With no load connected to the Antenna jack, SWR and Impedance (Z) will be very high, falling well outside the analyzer's normal measurement

range (greater than 25:1 and 650 Ohms):

10.140 MHz >25

Z>650) SWR

See Chapter-4.2 for complete measurement-mode R&X operating instructions.

3.0 VFO Frequency Control

The SWR-584C's expanded-coverage VFO spans the LF, HF, and VHF spectrum from 0.53 MHz (AM broadcast) to 230 MHz (135-cm) in nine bands.

3.1 Band Switching and Tuning: Two Frequency MHz switches select high and low bands.

The High-Frequency band switch must be set fully clockwise to enable the Low-Frequency

band switch (see below).

FREQUENCY MHz

67-113 28-67

113-155

155-230

2.1-4.7 1.0-2.1

TUNE

4.7-11

The VFO Tune capacitor features a reduction driver to provide smooth continuous frequency control with a small amount of overlap at each band edge.

3.2 LF (630 Meter) Modification: You may shift LF-VFO coverage down to the experimental 630-Meter band (472-479 kHz). First rotate Tune counter-clockwise to its stop (lowest frequency). Then, remove the back of the case (4 screws each side) and remove the battery tray (2 screws on right side). Find the access hole for the 0.53-1.0 MHz tuning slug at the very bottom-center of the pc board (only coil using a hex slug). Using a 2-mm insulated hex wand, adjust the inductor while watching the LCD frequency display for 0.47 Mhz. Coverage should now be ~0.47-0.94 MHz.

3.3 Signal Generator Function

: You may use the output signal from the analyzer's internal

VFO as a discrete signal source (or signal generator) for testing purposes. Connect via the SO-239 Antenna jack. Signal level is approximately 3-Vpp (20 mW into 50 Ohms or +5 dBm)

11-28

Lower Range

0.53-1.0

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

with all harmonics suppressed below -25 dBc. Although not phase-locked, stability is adequate for most general alignment applications. To protect the bridge diodes from accidental DC voltage applications, we strongly recommend installing an in-line attenuator or coupling capacitor to provide isolation.

4.0 Basic Measurement Modes

4.1 The Basic Operating Menu:

frequently used measurement functions. Tap the Mode switch to step through each one -- or hold it down to scroll through them at a 3-second-per-screen rate. Selections are:

1. R&X: Measures SWR, R (Resistance), X (Reactance), Z (Z-magnitude), and  (Phase).

2. Coax Loss (dB): Measures loss at any given frequency for 50-Ohm coax or a DUT.

3. Capacitance (pF): Measures component's reactance, computes capacitance.

4. Inductance (uH): Measures component's reactance, computes inductance.

5. Frequency (MHz): Counter mode, measures frequency of an external RF source

Each menu selection opens with an Identifier Screen*. After a brief pause, a Working Screen

appears to present data. The menu is circular, reverting back to the beginning.

*On analyzer boot-up, the R&X Working Screen appears without its identifier screen. However, the Identifier Screen will appear when stepping or scrolling through the menu:

4.2 Measuring SWR, R, X, Z, and 

most widely used network parameters simultaneously. To access and view measured data for SWR, R, X, Z, and , follow the checklist below:

[ ] Turn on the analyzer and allow it to boot to the default mode (R&X). [ ] Adjust the Frequency switches and Tune control to the desired test frequency (MHz). [ ] Connect the feedine (or load) to the analyzer's Antenna jack.

[ ] Read numerical Standing Wave Ratio (SWR) in the upper right-hand corner of the display:

[ ] Also, read SWR on the analog panel meter display:

The SWR-584C Basic Menu presents the analyzer's most

Impedance R &

: This default function measures and displays five of the

10.120 MHz 1.5

R= 73 X=5 SWR

2.0

2.5

1.5

1.2

SWR

[ ] Read Complex Impedance (R and X) on the bottom line of the display:

SWR-584C Instruction Manual HF/VHF/220MHz SWR Analyzer

10.120 MHz 1.5

R= 73 X=10

[ ] Read Impedance Magnitude (Z) on the analog meter scale.

70 100

Ohms

400

[ ] Read Impedance Magnitude (Z) and Phase Angle () presented numerically by pressing and holding the Gate button. The LCD display changes, as shown below:

10.120 MHz 1.5

Z= 75 = 5° SWR

[ ] Release Gate to revert back to R&X.

Note that Reactance readings (X) could be inductive (+ XL) or capacitive (- Xc) because the

processor can't calculate the sign. However, you can often find the sign by installing a small capacitor across the feedline connector to add a few ohms of capacitive reactance. If your capacitor increases X, the load is likely capacitive (-) because your reactance added to it. On the other hand, if your capacitor caused X to decrease, the load is likely inductive (+) because it cancelled out some of the X. To ensure accuracy, keep the amount of Xc you add as small as possible.

Also, when measuring through a feedline, always remember the values for R, X, Z, and  are

displaced values measured at the analyzer's calibration plane and do not represent the actual impedance of the device connected at the far end. To read the impedance of the device under

test accurately, you must connect directly to the DUT using the shortest leads possible (or use an electrical half-wave of 50-Ohm cable) .

4.3 Measure Coax Loss (dB)

: This mode displays the Measured Loss in dB at the VFO

operating frequency for any length of 50-Ohm coax cable. It will also measure losses incurred

through 50-Ohm attenuators, transformers, or baluns. To measure Loss:

[ ] Turn on the analyzer and allow it to boot to the default mode (R&X).

[ ] Press Mode once to access Coax Loss and wait for the working screen.

[ ] Adjust the Frequency switches and Tune control to the desired test frequency (MHz). [ ] Connect the feedine under test (or 50-Ohm device) to the Antenna jack.

[ ] Make sure the far end of the coax or the output port of the device is unterminated.

[ ] Read Coax Loss on the lower line of the LCD display:

10.120 MHz

Coax Loss = 2.1 dB

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