The following are general safety precautions that are
not necessarily related to any specific part or
procedure, and do not necessarily appear elsewhere in
this publication. These precautions must be
thoroughly understood and applied to all phases of
operation and maintenance.
Resuscitation
Personnel working with or near high voltages should
be familiar with modern methods of resuscitation.
Keep Away From Live Circuits
Operating personnel must at all times observe normal
safety regulations. Do not replace components or make
adjustments to the equipment with high voltage
turned on. To avoid casualties, always remove power.
Do Not Service Or Adjust Alone
Under no circumstances should any person reach into
an enclosure for the purpose of service or adjustment
of equipment except in the presence of someone who is
capable of rendering aid.
Safety Earth Ground
An uninterruptible earth safety ground must be
supplied from the main power source to test
instruments. Grounding one conductor of a twoconductor power cable is not sufficient protection.
Serious injury or death can occur if this grounding is
not properly supplied.
i
Bird AT-100 Antenna Tester
Shock Hazard
Do not attempt to remove the RF transmission line
while RF power is present. Radiated RF power is a
potential health hazard.
Safety Symbols
WARNING
Warning notes call attention to a procedure which, if
not correctly performed, could result in personal injury.
CAUTION
Caution notes call attention to a procedure which, if
not correctly performed, could result in damage to
the equipment.
The caution symbol appears on the
equipment indicating there is important
information in the instruction manual
regarding that particular area. See page 16
and 37 for specific cautions.
NOTE: Calls attention to supplemental informa-
tion.
Warning Statments
The following equipment cautions appear in the text
whenever there is a danger to people.
WARNING
Live RF energy. Do not touch or ground the center
conductor of a live RF connection. Failure to
comply may result in equipment damage and
serious burns or death to personnel.
ii
Caution Statements
The following equipment cautions appear in the text
whenever the equipment is in danger of damage and
are repeated here for emphasis.
CAUTION
Required input is 11 to 16 VDC @ 250mA. Connector
is wired outside positive, inside negative.
CAUTION
AVOID STATIC DISCHARGE
Use proper Electrostatic Discharge (ESD)
precautions to avoid static discharge when making
connections to the test port. Equipment failure can
occur if the test port is subjected to ESD.
CAUTION
250mW max. input
Exceeding the maximum input will cause damage to
internal components. Do not connect transmitter
output to the AT-100. Damage can also be caused by
testing antennas near other transmitting antennas. If
testing base station antennas, first measure the power
at the coax end to be sure it does not exceed 250mW.
CAUTION
Harsh or abrasive detergents and some solvents can
damage the display unit and information on labels.
iii
Bird AT-100 Antenna Tester
CAUTION
Replace with only NiCad rechargeable AA batteries,
IEC code KR-15/51. Nominal Voltage 1.2V; Capacity
650mAhr. Do not install alkaline batteries.
CAUTION
Replace with only the same type and rating fuse.
315mA 250V
Safety Statements
USAGE
ANY USE OF THIS INSTRUMENT IN A
MANNER NOT SPECIFIED BY THE
MANUFACTURER MAY IMPAIR THE
INSTRUMENT’S SAFETY PROTECTION.
USO
EL USO DE ESTE INSTRUMENTO DE MANERA NO
ESPECIFICADA POR EL FABRICANTE, PUEDE ANULAR
LA PROTECCIÓN DE SEGURIDAD DEL INSTRUMENTO.
BENUTZUNG
WIRD DAS GERÄT AUF ANDERE WEISE VERWENDET
ALS VOM HERSTELLER BESCHRIEBEN, KANN DIE
GERÄTESICHERHEIT BEEINTRÄCHTIGT WERDEN.
UTILISATION
TOUTE UTILISATION DE CET INSTRUMENT QUI N’EST
PAS EXPLICITEMENT PRÉVUE PAR LE FABRICANT
PEUT ENDOMMAGER LE DISPOSITIF DE PROTECTION
DE L’INSTRUMENT.
IMPIEGO
QUALORA QUESTO STRUMENTO VENISSE
UTILIZZATO IN MODO DIVERSO DA COME
SPECIFICATO DAL PRODUTTORE LA PROZIONE DI
SICUREZZA POTREBBE VENIRNE COMPROMESSA.
iv
SERVICE
SERVICING INSTRUCTIONS ARE FOR USE
BY SERVICE - TRAINED PERSONNEL ONLY.
TO AVOID DANGEROUS ELECTRIC SHOCK,
UNLESS QUALIFIED TO DO SO.
SERVICIO
LAS INSTRUCCIONES DE SERVICIO SON PARA USO
EXCLUSIVO DEL PERSONAL DE SERVICIO
CAPACITADO. PARA EVITAR EL PELIGRO DE
DESCARGAS ELÉCTRICAS, NO REALICE NINGÚN
SERVICIO A MENOS QUE ESTÉ CAPACITADO PARA
HACERIO.
WARTUNG
ANWEISUNGEN FÜR DIE WARTUNG DES GERÄTES
GELTEN NUR FÜR GESCHULTES FACHPERSONAL.
ZUR VERMEIDUNG GEFÄHRLICHE, ELEKTRISCHE
SCHOCKS, SIND WARTUNGSARBEITEN
AUSSCHLIEßLICH VON QUALIFIZIERTEM
SERVICEPERSONAL DURCHZUFÜHREN.
ENTRENTIEN
L’EMPLOI DES INSTRUCTIONS D’ENTRETIEN DOIT
ÊTRE RÉSERVÉ AU PERSONNEL FORMÉ AUX
OPÉRATIONS D’ENTRETIEN. POUR PRÉVENIR UN
CHOC ÉLECTRIQUE DANGEREUX, NE PAS
EFFECTUER D’ENTRETIEN SI L’ON N’A PAS ÉTÉ
QUALIFIÉ POUR CE FAIRE.
ASSISTENZA TECNICA
LE ISTRUZIONI RELATIVE ALL’ASSISTENZA SONO
PREVISTE ESCLUSIVAMENTE PER IL PERSONALE
OPPORTUNAMENTE ADDESTRATO. PER EVITARE
PERICOLOSE SCOSSE ELETTRICHE NON
EFFETTUARRE ALCUNA RIPARAZIONE A MENO CHE
QUALIFICATI A FARLA.
DO NOT PERFORM ANY SERVICING
v
Bird AT-100 Antenna Tester
About This Manual
About this Manual
Many people read the operators manual only as a last
resort. If you are one of those people, you should at
least read the next two pages so that you can find the
information when you do need it. You will also learn
where to find valuable time saving information.
Changes to this Manual
We have made every effort to ensure this manual is
accurate at the time of publication. If you should
discover any errors or if you have suggestions for
improving this manual, please send your comments to
our factory. This manual may be periodically updated,
when inquiring about updates to this manual refer to
the part number and revision level on the title page.
Typography
There are two types of keys on the Antenna Tester. A
Hard Key is a key that has a particular function and it
is indicated on the key. These key names are set in a
bold typeface, e.g. Press the MENU key.
A Menu Select Key, (there are five under the display),
will have a different label, or name, depending on the
selected function. The name will be at the bottom of
the display located directly above the corresponding
key. These key names are set in a bold Italic typeface,
e.g. Press the SWEPT FREQ key.
vi
Chapter Layout
Introduction—Will help you become familiar with
the parts of the Antenna Tester, Features Available,
and Optional Equipment.
Basic Operation—Everyone should read this section!
This section will provide the information required to
get the Antenna Tester powered up, and provides
helpful information about how to operate the Antenna
Tester, and some time saving hints for alternate
operating methods.
Installation—This chapter contains the information
on how to connect the AT-100 to antenna systems, and
to power sources to charge and operate the unit.
Measure Match—Since the AT-100 Antenna Tester
offers a unique method of measuring Antenna Systems
we have included the section, “Understanding the
Operating Modes.” Even if you already know the
basics of antenna match testing you might find this
section useful. The remainder of the chapter provides
step by step instructions for measuring match.
Field Strength—Provides step by step instructions
for measuring relative field strength of fixed antennas.
Maintenance—This chapter contains the information
required to keep the AT-100 working for you. This
includes battery and fuse information, troubleshooting
information, parts lists, and specifications.
Connect either the ac adapter or the
cigarette lighter adapter. External
supplies operate the unit and charge
the internal battery.
2
6
5
Introduction
3.Cursor Keys
Left Arrow
Right Arrow
Up Arrow
Down Arrow
4.Backlight KeyTurns the backlight on or off. Backlight
5.On KeyPress to turn tester on, press and hold
6.+/- KeyToggles between positive and negative
7.Enter KeyCompletes data entry.
8.ESC Key
9.Menu KeyDisplays software menu and enables
10. Select KeyAllows current parameter, indicated by
11. Numeric KeysInput numeric values.
12. Menu Select
Keys
13. Test PortConnect antenna or antenna lead.
14. Serial PortConnect communication cable to allow
Press in swept frequency mode to move
the cursor to the left. Press during data
entry to erase data.
Press in swept frequency mode to move
the cursor to the right.
Moves the cursor to the maximum point
on the displayed trace. Press during
data entry to increase numeric data.
Moves the cursor to the minimum point
on the displayed trace. Press during
data entry to decrease numeric data.
is on a timer to increase battery life.
to turn tester off.
numbers.
Back up through menu structure. At the
top menu level, blanks menu. Exits data
entry without saving changes.
menu select keys.
flashing cursor, to be changed. Press
again to enable the next parameter to
be changed.
Used to access the menu sections
described directly above them. Can also
be used to scroll through available
settings in a particular parameter.
data transfer to a PC.
3
Bird AT-100 Antenna Tester
Display Description
2.0
1
2
3
4
*
VSWR
1.0
2.00MHz136.00
Band
1.2
Meas
Units
1.35
69.00 MHz
Sweep
Type
1.35
69.00 Mhz
1.5
8910
8910
Busy
LimitTrace
7
6
5
2
4
Freq
MHz
Units Manual
Figure 3 Display Description
4
VSWR
Scale
Auto
Scale
Low
Batt
Audio
Off
7
14
Introduction
1.Sweep Rate
Indicator
2.Measurement UnitsIndicates selected measurement
3.TraceGraphic display of measured
4.Menu Select Key
Labels
5.Frequency Band
Scale
6.CursorUsed to select measurement
7.Utility LabelArea for displaying general data
8.FrequencySelected Frequency (for swept
9.Measured ValueNumeric display of measured
Blinks when sweeping.
units.
results across selected frequency
band.
Defines function of menu select
keys located below the display.
Displays frequency band selected.
position on the trace.
(Lo Batt, Busy, Hold, Noise, and
test results).
mode this is frequency at the
cursor position).
value (for swept mode this is the
value at the cursor position).
10. ScaleDisplays user defined
measurement scale.
11. PointerMoves across scale to show analog
type indication of measured
value.
5
Bird AT-100 Antenna Tester
Features
Swept Frequency Mode — Fast scan shows VSWR, ρ,
match efficiency or return loss across an entire band. A
movable cursor can be used to pinpoint a scan frequency and
the corresponding measurement value is displayed.
Single Frequency Mode — Provides measurement
information in units of Reflection Coefficient (
Standing Wave Ratio (VSWR); % Match, or Return Loss (dB)
at one frequency on a simulated meter movement. An audio
generator can be enabled to produce a tone that is
proportional to the match condition.
Auto Scaling — Used in either swept or single frequency
modes, sets the Y axis for best measurement display.
Relative Field Strength — Provides means for optimizing
the radiated signal of any transmitter within the specified
frequency band.
Limit Testing — Quick pass-fail indication; compares
measurements to user selected limits.
Data Storage — Saves and recalls up to 12 traces to be used
to set limit or long term monitoring of antenna performance.
ρ); Voltage
Serial Communication Link — Built in serial port and
optional software uploads data to a personal computer for
analysis or storage.
6
Introduction
Optional Equipment
Automobile Cigarette Lighter Adapter — (P/N 5A2238-1)
Connects tester to standard 12V automotive cigarette lighter
jack.
Carrying Case — (P/N 5000-030) Convenient and protective,
large enough to carry the tester, AC adapter, connectors,
field strength antenna and instruction book.
Verification Kit — (P/N 7000A145) Used to verify tester
performance. Includes standard mismatch and connector
adapter.
Interface Software — (P/N 7000A840) PC software used to
upload trace data for analysis, printing or storage.
System requirements: IBM PC or equivalent; Windows 95 or
later, 4 MB free hard disk space; VGA monitor, open com
port. Includes interface cable.
7
Bird AT-100 Antenna Tester
8
Chapter 2Basic Operations
Getting Started
This section describes initial quick steps to get started. For
detailed information regarding connecting the Antenna
Tester refer to that section at the end of this chapter.
Note: This unit is shipped with the batteries not
charged. Charge batteries overnight or for at least 8
hours before use.
ON
Power On/Off
yTo turn the Antenna Tester on, momentarily press the
ON key. The results of a self test will be displayed if a
failure is present. For more information about the self
test or a failure, refer to the maintenance section.
yTo turn the Antenna Tester off, press and hold the ON
key for 1 second.
Backlight
yTo turn the backlight on, press the BACKLIGHT key.
yTo increase or decrease display contrast, press and hold
the BACKLIGHT key while pressing either the UP or
DOWN arrow key.
yTo turn the backlight off, press the BACKLIGHT key.
Software Menu
MENU
yPress the MENU key to display the software menu.
9
Bird AT-100 Antenna Tester
Blinking Cursor (black square)
The cursor will be blinking in the selected area, indicating
that the parameter for that area can be changed.
Enter Key
ENTER
All data entry, and mode changes accessed using select key,
require the enter key to be pressed before they are initiated.
Up/Down Arrow Keys
When a function is enabled for change, the UP or DOWN
arrow keys can be used to either scroll through your choices
or increase/decrease the numerical value. The actual
increments depend on the function.
Left Arrow Key
The LEFT arrow key can be used to backspace erasing one
character at a time during data entry.
Escape (ESC)
ESC
Returns to previous menu without initiating a change.
Select Key
The operator instructions written for this manual were
based on stepping through the software menu using the keys
below the display. Once you are comfortable operating the
AT-100, you might find it faster to use the SELECT key to
access some functions. These include: Units, Scale, Start and
Stop Frequencies in swept frequency mode and Units, Scale
and Frequency in single frequency mode.
Press the SELECT key until the cursor is blinking at the
desired function. The first function enabled depends on the
last function selected through the menu.
10
Basic Operations
Messages
There are five utility messages that can be displayed to
inform you of equipment, or procedural, conditions.
“Lo Batt” is displayed when battery voltage is less than 6.6V,
refer to maintenance section for charging batteries.
“Busy” is displayed during mode changes indicating the
measurement information is being updated.
“Hold” is displayed when in the Swept Frequency mode, and
Single Hold is the selected sweep type.
“Pass” or “Fail” will be displayed indicating the appropriate
results of a limit test.
“Noise” will be displayed if there is excessive background
noise measured. The measurement may not be accurate. See
troubleshooting if this condition is persistent.
Out of Range Values
When entering numeric data, it is possible to enter a value
out of range. Depending on the function, the Antenna Tester
will either enter the minimum or maximum value, or the
cursor will continue to blink on the function out of range
waiting for the correct entry.
Setting the Auto Shut-Off Timer
In order to preserve battery life, the Antenna Tester will
automatically shut off after 5,15,30 or 60 minutes without
any keystrokes.
Follow the steps below to select the length of time, before
auto shut-off occurs.
yPress the MENU key.
yPress the UTIL key.
yPress the TIMER key until the desired interval is
displayed.
11
Bird AT-100 Antenna Tester
Return to Factory Presets
When the Antenna Tester is turned on, the various software
parameters will be set to the condition they were at when
the tester was turned off.
To return the parameters to the factory setting follow the
steps below.
y
The parameters will be set to the conditions listed below.
Software Parameter Factory Setting
Mode Swept Frequency
Start2.0MHz
Stop136.0MHz
Measurement Units VSWR
Scale min. 1.0; max. 5.0
Sweep Type Continuous
Limit Value1.5
Limit AudioON
Baud Rate 9600
Auto Shut-off Timer 5
Audio ON
Cursor67MHz
yPress the MENU key.
yPress the UTIL key.
yPress the PRESET key.
12
Basic Operations
Set Serial Baud Rate
Measurement data can be transferred between the AT-100
and a personal computer using the serial port and optional
interface software. The data can then be used for analysis,
printed, or stored.
The data transfer rate (baud rate) between the Antenna
Tester and computer must be identical and set to 9600. To
change the baud rate for the serial port on the Antenna
Tester, follow the steps below.
Complete interface software instructions are included with
the software.
yPress the MENU key.
yPress the UTIL key.
yPress the SERIAL key.
yRepeatedly press the SERIAL key until the 9600 is
displayed.
13
Bird AT-100 Antenna Tester
14
Chapter 3Installation
The following paragraphs will explain how to connect the
Bird Antenna Tester for various operations. Refer to the
component description diagram on page 2 if needed.
Power Supply
The AT-100 can use an external power source. Using the ac
adapter or the 12V cigarette lighter adapter will also charge
the battery. Using the ac adapter, charge time is about 8
hours. Using the cigarette lighter adapter, charge time will
depend on the car battery charge. Battery life is 2 hours
continuous operation, minimum, with the backlight on. “Lo
Batt” is displayed when the batteries require charging.
NOTE: This unit is shipped with the batteries not
charged. Charge batteries for at least 8 hours before use.
NOTE: For optimum battery life, only charge the
batteries after the low battery indicator is displayed.
CAUTION
Only use the ac adapter provided with the AT.
Do not use the adapter with the batteries removed.
yAC Mains Adapter — To use the ac adapter, insert the
adapter’s barrel connector into the Antenna Tester’s dc
jack. Insert the adapter plug into a wall receptacle.
CAUTION
Required input is 11 to 16 VDC @ 250mA. Connector is
wired outside positive, inside negative.
yAutomobile Cigarette Lighter Adapter — Insert the
adapter’s barrel connector into the Antenna Tester’s dc
jack. The negative (–) symbol must be adjacent to the
word TIP as the center is negative and the outside is
positive. Insert the adapter plug into a cigarette lighter.
15
Bird AT-100 Antenna Tester
Connecting the Antenna
Live RF energy. Do not touch or ground the center
conductor of a live RF connection. Failure to
comply may result in equipment damage and
serious burns or death to personnel.
AVOID STATIC DISCHARGE
Use proper Electrostatic Discharge (ESD)
precautions to avoid static discharge when making
connections to the test port. Equipment failure can
occur if the test port is subjected to ESD.
250mW max. input
Exceeding the maximum input will damage the unit.
Do not connect transmitter output to the AT-100.
Damage can also be caused by testing antennas near
other transmitting antennas. If testing base station
antennas, first measure the power at the coax end to
be sure it does not exceed 250mW.
WARNING
CAUTION
CAUTION
Antenna leads and the Field Strength Antenna are
connected to the test port. A known good RF cable can be
used to connect the antenna tester directly to a coupler box,
bypassing the antenna system lead. A female TNC connector
is provided. Other connectors are available, see Parts List in
the maintenance section for more information.
Special consideration must be given to the RF energy
present at the feed line of site antennas. At active sites, RF
energy from transmitters can be coupled to the antenna
under test. If large enough, these signals will cause
inaccurate measurements. For best results, the AT-100
should be used with all transmit antennas powered down.
16
Chapter 4Measure Match
Understanding the Operating Modes
The Antenna Tester is connected and the operating
frequency band is selected (see basic operation). User
selections are customized, the power is on, and the top level
menu is displayed (also in basic operation). Now what?
Before we explain how to measure the antenna match, a
brief discussion of your options is in order.
Since the AT-100 will change the way you test antennas, we
suggest taking some time to explore the different operating
modes and find what is best for your application.
Swept Frequency vs. Single Frequency
Swept frequency graphically displays the unit of measure
over a band of frequencies. The cursor, a vertical dotted line,
can be moved with the arrow keys to pinpoint a particular
frequency. The measured match value and the frequency at
the cursor position are shown at the top of the display.
Figure 4
Swept
Frequency
*
VSWR
1.5
1.3
69.00 MHz
5
1.2
2.00
Single
Freq
MHz136.00
Field
UtilTest
Str
Swept
Freq
Single Frequency mode displays the unit of measure in a
simulated analog meter graphic. This mode, particularly
when audio is on, is useful when tuning an antenna.
17
Bird AT-100 Antenna Tester
Figure 5
Single
Frequency
Freq
MHz
1.2
1.3
5
69.00 MHz
VSWR
Units Manual
Scale
1.5
Auto
Scale
Audio
Off
Measurement Units
Rho (Reflection Coefficient), VSWR (Voltage Standing Wave
Ratio), Match Efficiency (%), and Return Loss (dB), are
different units of measurement that can be used to present
the same information. (Similarly, Celsius and Fahrenheit
are different units of measurement used to express the same
temperature). These units can be used to express the degree
of match between an antenna system and a transceiver.
Rho is the ratio of reflected wave voltage to forward wave
voltage. A perfect antenna would not have any reflected
waves, hence would have a 0.00 reflection coefficient.
VSWR refers to the ratio of maximum and minimum
voltages that are set up on a transmission line resulting
from the combination of a forward wave and reflected wave.
If the antenna system is perfectly matched, the VSWR would
be 1:1 and shown as 1.00.
Match Efficiency (%) indicates how much of the
transmitted power is being used and how much is wasted. If
the antenna system is perfectly matched, the Match
Efficiency would be 100%.
Return Loss (dB) is a comparison of the reflected signal to
the forward signal in decibels. If the antenna system is
perfectly matched, the Return Loss would be negative
infinity dB.
18
Measure Match
Antenna manufacturers often use VSWR for specifications.
Match Efficiency is popular for testing because it is easy to
determine a good match versus a bad match. For example a
system with a VSWR of 1.50 would show -13.98 dB Return
Loss and 96% Match Efficiency.
Auto Scale vs. Manual Scale
In swept mode Auto Scaling sets the measurement unit scale
to make the trace easier to read. However, if you plan to look
at the size or shape of traces for quick comparisons, it might
be more meaningful to set a standard scale. Remember that
it is possible to set the scale manually so the information is
not on the display at all.
Figure 6
Auto Scaling
Swept
Frequency
Mode
*
VSWR
1.2
Swept
Freq
1.5
2.00
Single
Freq
1.3
5
69.00 MHz
MHz136.00
Field
UtilTest
Str
Figure 7
Manual
Scaling Swept
Frequency
Mode
*
VSWR
1.0
Swept
Freq
2.0
2.00
Single
Freq
1.3
5
69.00 MHz
MHz136.00
Str
UtilTestField
19
Bird AT-100 Antenna Tester
In the single frequency mode Auto Scaling sets the
measurement unit scale so the pointer is mid range of the
previous reading. The maximum and minimum scale values
are approximately 10% higher or lower than the measured
value.
Figure 8
Auto Scaling
Single
Frequency
1.2
1.3
69.00 MHz
5
1.5
Mode
VSWR
Freq
MHz
Units Manual
Scale
Auto
Scale
Audio
Off
This setting is an operator preference based on the mode
that best presents the desired information.
Figure 9
Manual
Scaling Single
Frequency
Mode
1.0
1.3
69.00 MHz
VSWR
5
5.0
Freq
Mhz
Units Manual
Scale
Auto
Scale
Audio
Off
Sweep Type-Single Hold vs. Continuous
Continuous sweep continually sweeps the selected frequency
band updating the measured value with each sweep. An
asterisk (*) is blinking on the left side of the display to
indicate sweep rate. The single hold mode will freeze a trace
on the display and hold is displayed on the right. Holding a
trace is also helpful before saving the trace, (more about
saving traces under that heading later in this section).
20
Measure Match
Swept Frequency
Select Frequency Band
There are two options for selecting the frequency band. The
first is simply to enter the start and stop frequencies. The
second is to enter a span frequency, which is the desired
width of the band, and a center frequency, that will be used
as the center of the band.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the BAND key.
yDepending on desired method press either Start Stop
MHz or Center MHz:
START STOP MHZ - The cursor will blink on the start
frequency and Start Stop MHz will be highlighted.
1.Enter the frequency using the numeric keypad or
change the frequency using the UP/DOWN arrow keys.
2.Press the ENTER key. The cursor will blink on the stop
frequency.
3.Enter the frequency using the numeric keypad or
change the frequency using the UP/DOWN arrow keys.
4.Press the ENTER key. The tester will begin sweeping.
CENTER MHz - The cursor will blink on the Center
frequency and Center MHz will be highlighted.
1.Enter the frequency using the numeric keypad or
change the frequency using the UP/DOWN arrow keys.
2.Press the ENTER key. The tester will begin sweeping.
3.Press the SPAN key. Enter the frequency using the
numeric keypad or change the frequency using the UP/DOWN arrow keys.
4.Press the ENTER key. The tester will begin sweeping.
21
Bird AT-100 Antenna Tester
Select Measurement Units
Antenna match information can be presented using four
different measurement units. Depending on your
application, follow the steps below to select Rho, VSWR,
%Match or Return Loss.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the MEAS UNITS key.
yPress the UNITS key.
yPress either the RHO, VSWR, %MATCH or RETURN
LOSS key. The selected unit will be shown on the left
side of the display.
yPress RETURN to go back one menu level or MENU to
return to the top menu level.
Select Auto or Manual Scale
Selecting the scale simply sets up how the information will
look on the display.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the MEAS UNITS key.
yDepending on desired mode press either AUTO or
MANUAL SCALE:
AUTO SCALE - the units scale changes and the Antenna
Tester begins sweeping.
MANUAL SCALE - the cursor will blink on the minimum
scale value and Manual Scale will be highlighted.
1.Enter the desired value using the numeric keypad or
change the value using the UP/DOWN arrow keys.
2.Press the ENTER key. The cursor will blink on the
maximum scale value.
3.Enter the desired value using the numeric keypad or
change the value using the UP/DOWN arrow keys.
4.Press the ENTER key. The tester will begin sweeping.
22
Measure Match
NOTE: If an out of range value is entered, the minimum
(if under-range) or maximum (if over-range) value will
be substituted. If a maximum value that is lower than
the minimum value is entered, the cursor will blink
again on the minimum value waiting for a correct entry.
The actual range depends on the units selected.
HINT: Using the arrow keys will keep you in the
acceptable range. If you are not sure if the larger value
should be at the top or bottom of the scale, press the
auto scale key to see where the software puts it.
Selecting the Sweep Type
Sweep types are continuous or single hold. Continuous will
sweep and update the trace automatically. Single hold will
sweep once and the trace will remain in the display. Each
time single hold is pressed, the trace is updated.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the SWEEP TYPE key.
yDepending on desired mode press either SINGLE
HOLD or CONT key. HOLD will be displayed if single
hold is selected. The tester begins sweeping if
continuous is selected.
Saving a Trace
The AT-100 can store up to 12 traces. A saved trace can be
used to evaluate long term antenna performance, compare
performance under different conditions or for comparison to
another antenna. A saved trace is also a powerful tool in
limit testing (more about limit testing later in this section).
The information can later be uploaded to a PC using optional
interface software and the serial port. Traces are stored in
nonvolatile memory so they are not lost when the Antenna
Tester is turned off.
Since the reflection coefficient is the information actually
saved when saving a trace, and everything else is calculated
from that, you have some flexibility when using the trace for
23
Bird AT-100 Antenna Tester
comparison. For example, if you save a trace displayed in
VSWR, you can compare it to a trace displayed in %Match.
You can also change the frequency band of the new trace to
effectively zoom in on a particular section of the saved trace.
This may be helpful in pinpointing a problem area in a failed
limit test.
Figure 10
Save a Trace
2.0
1.3
69.00 MHz
5
Reg-5
Empty
<HOLD>
More
Save
VSWR
1.0
Reg-1
Empty
2.00
Reg-2
Empty
MHz136.00
Reg-3
Empty
The desired units, band, and scale should be selected. You
should be in the single hold mode and the trace you want
stored should be displayed. If continuous sweep type is
selected, the trace displayed when you save will be stored.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the TRACE key.
yPress the SAVE TRACE key.
yPress a REG-n key that has empty displayed. If you
select a full register the new trace will overwrite the old
trace. If registers 1-4 are full press the MORE SAVE
key to access 5-8 and again to access 9-12. If needed, use
the ESC key to back up.
HINT: It is a good idea to keep a record of which traces
are in which register as they are identified by register
number only.
Recalling a Trace
Follow the steps below to recall a saved trace.
24
Measure Match
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the TRACE key.
yPress the RECALL TRACE key.
yPress the REG-n key for the desired trace, press the
MORE RECALL key to access 5-8 and again to access
9-12. If needed, use the ESC key to back up. The saved
trace will be displayed and the corresponding register
number will be shown at the bottom of the display.
NOTE: The arrow keys can be used to move the cursor,
and the corresponding measurement and frequency at
the cursor will be displayed. Remember the up arrow
key will move the cursor to the highest value on the
trace and the down arrow key will move it to the lowest.
yPress the RETURN key to return to register selection.
yPress the ESC key to return to trace menu.
Clearing a Trace
When a trace is no longer needed or you need to clear
registers for space, follow the steps below.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the TRACE key.
yPress the CLEAR TRACE key.
yPress the REG-n key for the desired trace, press the
MORE CLEAR key to access 5-8 and again to access 9-
12. If needed, use the ESC key to back up. The word full
will be replaced by empty at the selected register.
yPress the ESC key to return to the trace menu.
Limit Testing
Limit testing is a quick pass-fail test using operator defined
limits or a stored trace as a minimum for acceptability. Pass
25
Bird AT-100 Antenna Tester
or fail will be displayed at the top of the display and an
audible tone can be enabled to indicate a fail situation.
Limit testing is probably the most labor-efficient mode for
operating the AT-100. Since all the software settings are
retained when the tester is turned off, once the limit test is
set up its simply a matter of connecting the next antenna
system, turning on the power and reading pass or fail.
Turn Audio On/Off
Audio tone for fail indication.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the LIMIT key.
yPressing the AUDIO key will toggle between on and off.
Selecting Limit Values
Valid limit values depend on measurement units selected.
Valid entries are:
VSWR- between 1.0 and 100.0
%Match- between 0 and 100%
Return Loss- between -32 and 0 dB
RHO- between 0.000 and 1.000
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the LIMIT key.
yPress the VALUE key. The cursor will blink next to off.
yEnter the desired value using the numeric keypad or
change the value using the UP/DOWN arrow keys.
yPress the ENTER key. Pass or Fail will be displayed, a
tone will be heard for fail if audio is enabled.
26
Measure Match
Using a Trace as the Limit
The trace you want to use for the limit must be saved. You
can have the current antenna test running or start it after
you set up the limit test.
Figure 11
Dotted Outline
of Limit Trace
*
VSWR
1.0
Swept
Freq
2.0
1.3
5
69.00 MHz
2.00MHz136.00
Single
Freq
Field
Str
PASS
UtilTest
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the LIMIT key.
yPress the TRACE - > LIMIT key.
yPress the REG-n key where the trace is stored. A dotted
outline of the limit trace will be displayed with the new
trace displayed over it. Pass or Fail will be displayed.
NOTE: You can still move the cursor, change
measurement units, frequency band and scale. The
dotted outline of the limit trace will be automatically
adjusted to provide a direct comparison with the
antenna system under test.
27
Bird AT-100 Antenna Tester
Clearing a Limit
Follow the steps below to clear either an operator defined
limit value or a trace limit. The trace will still be stored in
memory, the limit value will be erased.
yPress the MENU key.
yPress the SWEPT FREQ key.
yPress the LIMIT key.
yPress the CLEAR LIMIT key.
The value field will change to off if an operator value was
being used, the dotted outline of the limit trace will be
removed if a trace was being used.
Single Frequency
This mode is useful for tuning antennas, particularly with
the audio on. The frequency can be selected following the
instructions below.
Selecting the Frequency
yPress the MENU key.
yPress the SINGLE FREQ key.
yPress the FREQ MHZ key. The cursor will be blinking
at the frequency and Freq MHz will be highlighted.
yEnter the desired frequency using the numeric keypad
or change the value using the UP/DOWN arrow keys.
yPress the ENTER key. The measured value and the
frequency will be shown at the top of the display.
28
Measure Match
Select Measurement Units
Antenna match information can be presented using three
different measurement units. Depending on your
application, follow the steps below to select Rho, VSWR,
%Match or Return Loss.
yPress the MENU key.
yPress the SINGLE FREQ key.
yPress the UNITS key.
yPress either the RHO, VSWR, %MATCH or RETURN
LOSS key. The selected unit will be shown in the center
of the display.
yPress the RETURN key to go back one menu level.
Select Auto or Manual Scale
Selecting the scale simply sets up how the information will
look on the display.
yPress the MENU key.
yPress the SINGLE FREQ key.
yDepending on desired method press either AUTO or
MANUAL SCALE:
AUTO SCALE - the units scale changes.
MANUAL SCALE - the cursor will blink on the maximum
scale value and Manual Scale will be highlighted.
1.Enter the desired value using the numeric keypad or
change the value using the UP/DOWN arrow keys.
2.Press the ENTER key. The cursor will blink on the
minimum scale value.
3.Enter the desired value using the numeric keypad or
change the value using the UP/DOWN arrow keys.
4.Press the ENTER key.
29
Bird AT-100 Antenna Tester
NOTE: If an out of range value is entered, the minimum
(if under-range) or maximum (if over-range) value will
be substituted. If a maximum value that is lower than
the minimum value is entered the cursor will blink
again on the minimum value, waiting for a correct entry.
The actual range depends on the units selected.
NOTE: Using the arrow keys will keep you in the
acceptable range. If you are not sure if the larger value
should be at the right or left side of the scale, press the
auto scale key to see where the software puts it.
Turn Audio On/Off
The pitch varies with the match condition allowing you to
tune an antenna without having to look at the display.
yPress the MENU key.
yPress the SINGLE FREQ key.
yPressing the AUDIO key toggles between on and off.
30
Chapter 5Field Strength
Field Strength Measurement
With the field strength antenna installed, the Antenna
Tester can be used to optimize the radiated signal of any
transmitter from 2 to 136MHz. This is a relative
measurement. The measurement sensitivity is such that a
full scale deflection will occur for a field of 8 Volts/Meter at
100 MHz. The gain factor can be adjusted to increase the
measurement sensitivity to 0.08 Volts/Meter.
Turn Audio On/Off
The pitch varies with the field strength.
yPress the MENU key.
yPress the FIELD STR key.
yPressing the AUDIO key toggles between on and off.
Enter Gain Factor / Select Auto Gain
Increasing the gain factor increases the measurement
sensitivity. Setting the gain to auto will set a gain factor so
that the pointer is in the middle of the scale.
yPress the MENU key.
yPress the FIELD STR key.
yPress either:
AUTO GAIN- the pointer moves to the approximate middle
of the scale.
GAIN- The cursor will blink on the gain value. Enter the
desired value using the numeric keypad or change the
value using the UP/DOWN arrow keys. Press the ENTER
key.
31
Bird AT-100 Antenna Tester
32
Chapter 6Maintenance
Cleaning
CAUTION
Harsh or abrasive detergents and some solvents can
damage the display unit and information on labels.
Clean the antenna tester and the display with a soft cloth
dampened with mild detergent and water only.
Calibration
For best performance and accuracy, the Antenna Tester
should be calibrated once every 12 months. Return the unit
to an authorized Bird Service Center.
Charging Batteries
Fully charged batteries will provide a minimum of 2 hours
continuous operation with the backlight on. Charging time is
typically 8 hours. The batteries are being charged when the
Antenna Tester is connected to AC, with the AC mains
adapter, or DC, with the automobile cigarette lighter
adapter. The unit does not have to be on to charge the
batteries.
NOTE: For optimum battery life, charge the batteries
only after the low battery indication is displayed.
33
Bird AT-100 Antenna Tester
Operational Tests
Power-up
There are several operational tests run at power up. The test
is displayed only if any of the tests fail. The results are
displayed to the right of the test as shown in Figure 12. If
you would like the test screen displayed regardless of
results, press any key while pressing the ON key at initial
power up. If any test fails, check the troubleshooting section
for possible correction. When displaying the tests as
described above, a stuck key will be indicated.
Figure 12
Power-up Self
Tes t
Firmware Rev—Revision date for the firmware installed.
Firmware Rev:10MAR94
NVRam:
Rom:
EEprom:
Ram:
A/D:
Tempr:
PLL:
Stuck Keys:
<Press ESC to continue>
Pass
Pass
Pass
Pass
Pass
Pass
Pass
00000000
NVram—
Rom—Checks for valid contents
EEprom—
Ram—
A/D—
Tempr—Checks for proper circuit operation
PLL—
Stuck_Keys—Checks if keys are depressed at power up.
34
Maintenance
Battery Test
The battery test checks the output voltage of the batteries.
The result is displayed in a simulated analog meter type
graphic with the value shown at the top of the display. The
scale is set from 6-8V.
Figure 13
Battery Test
6.0
7.71
Battery
Voltage
V
8.0
Return
If the voltage measured is less than 7V you should charge
the batteries.
NOTE: The AT-100 will shut off if the battery is too low
however, full accuracy is maintained at any battery
voltage.
Be sure the AC mains adapter is not connected.
yPress the MENU key.
yPress the TEST key.
yPress the BATT TEST key.
yPress the RETURN key to end the test.
Display Test
The display test is used to be sure that each area of the
display is functional. When the test is started the display is
filled with various characters. Each pixel then changes state,
either from black to white or white to black. If there is any
area that is not functional return the tester to Bird
Electronic for repair.
35
Bird AT-100 Antenna Tester
Figure 14
Display Test
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
Display Test 1234567890 ABCDEFGH
yPress the MENU key.
yPress the TEST key.
yPress the DISP TEST key.
yThe test is started.
yPress the ESC key to end the test.
Self Test
The self test is similar to the operational tests run at power
up described on page 34 of this section. The one difference is
the keypad test.
Figure 15
Self Test
Firmware Rev:10MAR94
NVRam:
Rom:
EEprom:
Ram:
A/D:
Tempr:
PLL:
Keypad:
<Press ESC to continue>
Pass
Pass
Pass
Pass
Pass
Pass
Pass
yPress the MENU key.
yPress the TEST key.
yPress the SELF TEST key.
36
Maintenance
yTo test the keypad, Press each key (except esc and on).
The value next to Keypad is hexadecimal and
corresponds to the key pressed. If the value does not
change for each key, refer to Troubleshooting in this
section.
yPress the ESC key to stop the test.
Battery Replacement
The NiCad batteries need to be replaced when fully charged
batteries provide less than 2 hours operation. Carefully
follow the instructions below to replace the batteries.
CAUTION
Replace with only NiCad rechargeable AA
batteries, IEC code KR-15/51. Nominal
Voltage 1.2V; Capacity 650mAhr. Do not
install alkaline batteries.
NOTE: To retain trace data stored in nonvolatile RAM,
leave the AC mains adapter connected during battery
replacement.
1.Lay the Antenna Tester, display side down, on a clean
surface.
2.Using a small standard screwdriver, remove six screws
from the back cover.
3.Lift the back cover approximately two inches above the
front cover.
4.Flip the back cover in the direction of the arrow shown
below. To avoid disconnecting P2, (battery connector),
lay the back cover next to the front.
5.Remove the old batteries.
6.Install the new batteries checking the orientation of the
positive and negative terminals. Polarity is indicated on
the case, and in Figure 16.
7.Be sure P2 is connected and the shock strips are still in
place.
8.Place the back cover over the front cover making sure it
is properly seated.
37
Bird AT-100 Antenna Tester
9.Replace the six screws.
10. Run the battery test on page 35 of this section.
Fuse Replacement
CAUTION
Replace with only the same type and rating fuse. 315mA
250V
yFollow the steps outlined in Battery Replacement
replacing the fuse where replacing the batteries is
indicated.
Figure 16 Battery / Fuse Replacement
38
P2 Battery ConnectorFuseShock Strips
Maintenance
Troubleshooting
Operator maintenance or service is limited to battery and
fuse replacement. Any other required service must be
performed at an authorized Bird Service Center.
Refer to the following paragraphs for help in isolating error
conditions.
The Antenna Tester will not power up.
Power for the Antenna Tester can be provided in three
ways—the internal batteries, an AC mains adapter or an
optional automobile cigarette lighter adapter. Try to power
the tester using each available means. The internal batteries
may need charged, or if recently replaced, are installed
incorrectly. The AC mains adapter may not be securely
connected, may be damaged, or there is no power supplied at
the wall receptacle. The internal fuse may have opened and
requires replacement.
If the unit was recently opened, recheck P2, the battery
connector, be sure it is securely connected. Follow the
instructions for battery and fuse replacement when opening
the unit.
NVRAM Test Fails
An NVRAM error indicates the information in nonvolatile
RAM, a type of memory, is not valid. The probable cause is
power was lost. When the unit is off, the batteries, if charged
and present, or power from the AC mains adapter, if
connected, supply power to retain stored trace data and
software settings. This information is lost if all power is
removed. Clear the error by pressing the ESC key. Be sure to
read battery charging and replacement sections if the
problem persists.
39
Bird AT-100 Antenna Tester
ROM, EEPROM, RAM, A/D, TEMPR, PLL Test Fails
Ensure the results are valid by repeating the self test or
turning the unit off then back on. If the problem persists
return the unit for service.
Stuck Keys Test Fails
If any characters other than 0 are displayed next to stuck
keys during power up test, perform the keypad test on
page 36 of this section. Remember, if a key is depressed
during power up to display the power up test results it is
normal for other characters to be displayed. If the key
remains stuck return the unit for service.
“Noise” is Displayed During Testing
The Antenna Tester measures background noise to
determine if nearby signals could cause an erroneous match
measurement. Power down all nearby transmitting
antennas. All interfering signals must be removed before
resuming measurement.
Antenna Tester indicates a Perfect Match
When measuring the match of an antenna in a high RF
environment, the Antenna Tester indicates a perfect match
(i.e. VSWR = 1.00, Return Loss = -32 dB, or Match Efficiency
= 100%). This is caused by the coupling of interfering signals
into the Antenna-Under-Test. If sufficiently strong, the
interfering signals can over-power the measurement signal
inside the Antenna Tester. Normally, this results in
degraded measurement accuracy. Bird Antenna Testers
minimize this effect by measuring the interfering signal
during the time between match measurements. The interferer magnitude is subtracted from the magnitude of the
measurement signal. For relatively small interferers (i.e.
interfering signal smaller than the measurement signal),
this technique yields approximately 10 dB better rejection. If
the interfering signal becomes larger than the measurement
signal, the correction output approaches zero, corresponding
40
Maintenance
to a perfect match. Measurement results are not accurate
under these circumstances. The remedy is to disable the
interfering source, if possible, or postpone the measurement
to a time when the interfering source is not operating.
Customer Service
Any maintenance or service procedure beyond the scope of
those in this chapter should be referred to a qualified service
center.
If you need to return the unit for any reason, contact the
Bird Service Center for a return authorization. All
instruments returned must be shipped prepaid and to the
attention of Bird Service Center.
For the location of the Sales Office nearest you, give us a call
or visit our Web site at:
http://www.bird-electronic.com
41
Bird AT-100 Antenna Tester
Parts List
Part NamePart Number
AT-100 Complete7000A101
Parts Supplied with
AT-100 Complete, or installed when shipped.
Battery (6 required)5A2230
Fuse5-1976-11
AC Mains Adapter, 115v5A2229
or
AC Mains Adapter, 230v5A2226
Female N Connector4240-403
Field Strength Antenna5A2228-3
Instruction Book920-AT100
Foam Shock Strips (2)5A2243
Includes Cable5A2264-9MF-10
Verification Kit7000A145
Carrying Case5000-030
5A2238-1
42
Maintenance
Specifications
Frequency Range 2 to 136 MHz
Frequency Resolution 20 kHz
Measurement Range
VSWR1.00 to 100.00
Match Efficiency 0 to 100%
Return Loss-32 to 0 dB
Rho0.000 to 1.000
Measurement Speed(Typical)
Single Frequency
Swept Frequency 1 Sweep/second
Test Port
Impedance50
Connector
Field Strength
Range0 to 100% Relative
Sensitivity
Power Requirements
BatteriesSix Rechargeable AA (KR-15/
External DC11 to 16 VDC 250mA
External AC Adapter 108 to 132, or 207 to 253 VAC
Interface Serial (female DB-9 connector)
Operating Temperature0°to 50°C (32° to 122°F)
Storage Temperature
Size (including connector)
Weight 1-3/4 lb (0.8 kg)
5 Readings/second
Ω nominal
(Field Interchangeable) Female N
Full scale deflection at 8 Volts/
Meter at 100 MHz, depending
on gain setting.
51)
@ 48 to 63 Hz
-40° to 71°C (-40° to 160°F)
8" x 4-5/8" x 1-3/4”
(204mm x 118mm x 42mm)
43
Bird AT-100 Antenna Tester
Menu Structure
Return
Util
Field Str
Single Freq
Return
Ba t t Te st D is p Tes t S e lf Te st
Tes t
Timer Prese t Return
Serial
Gain Auto Gain Audio (ON, OFF)
Audio (ON, OFF)Auto ScaleManual Scale
Units
Freq MHz
Rho
VSWR % Match Return LossReturn
Audio (ON, OFF)
Trace -> Lim Clear LimitReturn
Recall Trace Clear Trace Return
Val ue
Save Trace
Single Hold Cont Return
Band Meas Units Sweep Type Trace Limit
Rho
Return
Units Manual Scale Auto Scale
Return
% Match Return LossReturn
VSWR
Start / Stop MHz Center MHz Span MHz
44
Swept Freq
Limited Warranty
All products manufactured by Seller are warranted to be free from
defects in material and workmanship for a period of one (1) year,
unless otherwise specified, from date of shipment and to conform to
applicable specifications, drawings, blueprints and/or samples.
Seller’s sole obligation under these warranties shall be to issue credit,
repair or replace any item or part thereof which is proved to be other
than as warranted; no allowance shall be made for any labor charges
of Buyer for replacement of parts, adjustment or repairs, or any other
work, unless such charges are authorized in advance by Seller.
If Seller’s products are claimed to be defective in material or
workmanship or not to conform to specifications, drawings,
blueprints and/or samples, Seller shall, upon prompt notice thereof,
either examine the products where they are located or issue shipping
instructions for return to Seller (transportation charges prepaid by
Buyer). In the event any of our products are proved to be other than
as warranted, transportation costs (cheapest way) to and from
Seller’s plant, will be borne by Seller and reimbursement or credit
will be made for amounts so expended by Buyer. Every such claim for
breach of these warranties shall be deemed to be waived by Buyer
unless made in writing within ten (10) days from the date of
discovery of the defect.
The above warranties shall not extend to any products or parts
thereof which have been subjected to any misuse or neglect, damaged
by accident, rendered defective by reason of improper installation or
by the performance of repairs or alterations outside of our plant, and
shall not apply to any goods or parts thereof furnished by Buyer or
acquired from others at Buyer’s request and/or to Buyer’s
specifications. Routine (regularly required) calibration is not covered
under this limited warranty. In addition, Seller’s warranties do not
extend to the failure of tubes, transistors, fuses and batteries, or to
other equipment and parts manufactured by others except to the
extent of the original manufacturer’s warranty to Seller.
The obligations under the foregoing warranties are limited to the
precise terms thereof. These warranties provide exclusive remedies,
expressly in lieu of all other remedies including claims for special or
consequential damages. SELLER NEITHER MAKES NOR
ASSUMES ANY OTHER WARRANTY WHATSOEVER, WHETHER
EXPRESS, STATUTORY, OR IMPLIED, INCLUDING
WARRANTIES OF MERCHANTABILITY AND FITNESS, AND NO
PERSON IS AUTHORIZED TO ASSUME FOR SELLER ANY
OBLIGATION OR LIABILITY NOT STRICTLY IN ACCORDANCE
WITH THE FOREGOING.
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