Monacor SWR-2 Operator's manual

USER INSTRUCTION MANUAL
MONACOR SWR and FIELD STRENGTH METER

1
INTRODUCTION
Your Field-Strength SWR Meter helps you tune your CB or amateur radio
system for the best performance.
CB and amateur radio systems work best when the antenna system’s
impedance matches the transmitter’s output impedance as closely as possible.
The meter’s standing wave ratio (SWR) function helps you trim your antenna
to the precise length you need for the maximum transmitted power.
The meter’s field strength function helps you position your antenna for the
best coverage and determine the effectiveness of changes you make to your
antenna, antenna cable, and transmitter.
Carefully read all of these instructions to get the best use from this meter.
Warning: You can use this meter to make measurements on equipment that
uses high voltages. Carefully observe all safety precautions provided with the
equipment you are testing.
Note: You need a separate 50-ohm coaxial cable (such as RG-58U) with a
PL-259 connector connected to both ends, long enough to reach from your
radio’s antenna jack to the back of the meter.
CONTENTS
Measuring SWR 2
Connecting the Meter 2
Calibrating the Meter/Measuring SWR 2
Interpreting SWR Readings 3
Improving SWR 4
Measuring Field Strength 4
Preparing the Antenna Site 4
Calibrating the Meter/Measuring Field Strength 6
Using Field Strength Readings to Tune Your Antenna 7

2
MEASURING SWR
Measuring SWR shows you how much of your radio’s transmit power is
reflected from the antenna back into the antenna cable, generating heat and
wasting power. With this information, you can adjust the length of your
antenna or antenna cable so your antenna and radio combination can
produce the maximum power they are capable of producing.
CONNECTING THE METER
To connect this meter to your CB or amateur radio and your antenna, you
need RG-58U coaxial cable (not supplied) with a PL-259 connector on both
ends. The cable must reach from the back of the meter to your radio’s
antenna jack.
1. Turn off your radio. Then disconnect the antenna from the radio and
plug it into ANTENNA on the back of the meter.
2. Plug the coaxial cable into the radio’s antenna jack and into
TRANSMITTER on the back of the meter.
CALIBRATING THE METER/ MEASURING SWR
1. Set Switch on the front of the meter to FWD.
2. Turn on your radio. Then select a channel or frequency on your
transmitter and hold down the transmit key. Do not speak into the
microphone.
3. While you hold down the transmit key, move the sliding ‘Level Adjust’
control until the needle points to SET.
4. Release the transmit key, then set the switch to REF.
5. Press the transmit key again, then read the SWR by noting the
needle’s position on the upper SWR scale. A meter reading of 1 on the
upper scale is ideal.

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Notes:
· An SWR reading will be different for different frequencies
(channels/bands). If you transmit on one band more often than any
other, select a channel within that band (e.g. UK or CEPT). If you
transmit on several bands, choose a frequency in the middle of the
range of channels you use. (For example, if you transmit on CEPT
and UK 40 channels, choose CEPT Channel 40, because it is as
near as midway as you can get)
· If you use a CB that has sideband modes (SSB), do not select any
of these modes. (Use only AM for SWR measurements).
· If you have an amateur radio, select the continuous wave (CW) or
tuning mode to check the SWR.
SWR Scales
The figure shown between the upper and lower scales on the meter (% REF
POWER) indicates the percentage of power that is wasted through reflection
of the signal from the antenna back into the antenna cable. For example, an
SWR reading of 1.5 also means that 4% of your signal power is lost. However,
96% of the radio power is more than enough for almost all applications.
Repeat Steps 1–5 for any other channel, band or frequency you want to get
an SWR reading for.
INTERPRETING SWR READINGS
An ideal SWR reading is 1.0, but this reading is usually possible only under
laboratory conditions or with a dummy load. Actual antenna installations have
higher readings. The information below will help you interpret the readings
you get.
SWR Efficiency Interpretation
1 to 1.5
Excellent
Antenna cable and the antenna length match the
transmitter’s output requirements almost perfectly
1.5 to 2.0
Very good
Antenna, cable, and transmitter operate efficiently
2.0 to 3.0
Acceptable
Antenna, cable, and transmitter operate with some
loss. If possible, adjust your antenna or antenna
mounting system to improve
Above 3.0
Inefficient
Adjust your antenna or antenna mounting system to
improve efficiency. WARNING: Continued use is
likely to cause damage to your transmitter

4
IMPROVING SWR
There are several ways to improve the SWR of your radio/antenna
combination.
Try these first.
· Be sure you are using the type of cable recommended for your
equipment. If the manufacturer recommends a 50ohm cable, do not
substitute another type that has different impedance.
· Confirm that you mounted your antenna according to the
manufacturer’s instructions. The angle and the base arrangement can
affect the SWR reading.
· Adjust the length of your antenna according to the instructions provided
by the manufacturer. A change of as little as 1/16 inch can make a
measurable difference.
· See your radio’s and antenna’s owner’s manuals.
MEASURING FIELD STRENGTH
Your meter can measure the low levels of radio frequency (RF) generated by
a radio transmitter. You can use these measurements to map the transmitting
direction and coverage pattern of your antenna, or to compare your radio and
antenna’s efficiency before and after an adjustment.
You do not need to connect the meter to the antenna or the radio to measure
field strength.
It takes two people to measure field strength. For an accurate measurement,
you will need to map the site around your antenna. Then, while someone
presses the radio transmit key, you will need to walk around the site around
your antenna with the meter, marking the readings you see.
Hints:
In addition to the meter, we recommend you use the following items to help
you measure field strength:
· Several photocopies of the template
· 36 objects such as rocks or weighted pieces of paper
· 25 feet of rope or strong cord
· Calculator
· Pencil
· Compass
• Make sure there is at least 25 feet of open space in all directions around
your antenna. 10
PREPARING THE ANTENNA SITE
Before you use the meter to measure field strength, you should mark the site
around the antenna in a pattern that will help you make the measurement. An
easy way to do this is to map the area around your antenna using a template
like this one.

5
Antenna Location
The template shows an imaginary circle around an antenna. The spokes on
the template represent imaginary straight lines measured from the centre of
the circle to 36 points spaced equally around the circle. Each straight line is
25 feet in length. The numbers on the template (1–5) are a guide to show you
where to mark the field strength level the meter displays as you measure.
Hint: To help measure a circular path around the antenna, tie a slip knot in a
25-foot piece of rope or strong cord, slide the knot loosely around your
antenna, then use the rope as a guide as you walk around the antenna.
Follow these steps to prepare the antenna site.
· Starting at the antenna, use a compass to find due north. Then walk
due north and stop about 15 to 25 feet away from the antenna.
· Use an object such as a rock or a weighted piece of paper to mark
where you are standing.
· Walk around the antenna in a circle, using more objects to mark 35
more evenly spaced marks on the path.
Hint: You can quickly find the space to leave between each mark by using a
calculator. Measure the diameter of the marked circle (from one side of the
circle to the other). Then, divide the diameter by 11.46.
For example, for a 50-foot diameter circle:
50 feet
= 4.363 Feet
11.46
So, you would place a mark every 4.363 feet (4 feet, 3 inches).
CALIBRATING THE METER/ MEASURING FIELD STRENGTH

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1. Ensure you have the wire antenna attached inserted it into FS ANT near
the top of the meter.
2. Set FWD/REF to FWD
3. To calibrate the meter, have your helper select a channel or frequency on
your transmitter and hold down its transmit key. Tell the helper not to
speak into the microphone. Then, while the helper holds down the transmit
key, walk around inside the marks you made using the steps in “Preparing
the Antenna Site” earlier, covering as much area inside the circle as you
can. As you walk, watch the meter’s needle. If it moves to the right of 5 on
the FIELD STRENGTH scale, moved the sliding control on the front of the
meter until the needle lines up with 5 on the scale.
4. To measure field strength, as the helper continues to hold down the
transmit key, move to the marked spot on the circle due north of the
antenna, then watch the meter’s needle. Note the reading on the FIELD
STRENGTH scale and place a dot on the template corresponding to the
reading at that point.
In this example, the needle shows a 4 on the FIELD STRENGTH scale.
Place a dot where the spoke representating the path you walked from the
centre of the circle intersects the circle marked with a 4 on the template.
Notes:
· If you use a radio that has sideband modes (SSB), do not select any of
these modes. (Use only AM for field strength measurements)
· If you have an amateur radio, select the continuous wave (CW) or
tuning mode to check the field strength.
5. Move to each marked spot along the circular path then repeat Step 4 for
each one, taking another reading and recording that reading on the
template.
Here is an example of a completed template. It shows an antenna mounted
on the rear bumper of an automobile that is parked facing north. The field
strength readings form a two lobed pattern when plotted, meaning the
antenna’s power is greatest at the front, weaker at the back, and almost
nonexistent at the sides.

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USING FIELD STRENGTH READINGS TO TUNE YOUR RADIO AND
ANTENNA
You can use field strength measurements to monitor the effectiveness of
changes you make to your radio and antenna while you make them.
Changes you might make include:
· Installing a new antenna or antenna cable
· Adjusting the length of an antenna Changing the antenna mount on
your vehicle
· Adjusting your radio’s transmitter
You do not need to connect the meter to the antenna or the radio to measure
field strength, but you will need two people. While someone presses the radio
transmit key, you will need to note the readings you see on the meter.
While the helper holds down the transmit key, walk around and adjust the
meter’s knob until the meter’s needle moves to 3 on the FIELD STRENGTH
scale.
Have the helper release the transmit key, then make a change to your radio or
antenna (such as adjusting the antenna or transmitter or adding a new
antenna).
When the change is completed, have the helper hold down the transmit key
again while you watch the meter’s needle.
If the field strength reading is higher, you have probably improved the power
output and efficiency of your radio and antenna.
Note: If you move the physical location, or change the transmission direction,
of your antenna, you might have to recalibrate the meter and measure the
field strength again. See “Calibrating the Meter/Measuring Field Strength”