Ritron Patriot PBS-446D User manual

TYPE OF EXHIBIT: OPERATIONAL DESCRIPTION
FCC PART: 2.1033 (c)(6)
MANUFACTURER: RITRON, INC.
505 West Carmel Drive
Carmel, IN 46032
MODEL: PBS-446D
TYPE OF UNIT: UHF-FM Base Transceiver
FCC ID: AIERIT16-446
DATE: December 9, 2002
Included in this exhibit is a draft of the Maintenance and Operating Manual for the Ritron Patriot Model
PBS-446D UHF-FM Base Transceiver.
Specifically, the manual includes a technical description of the PBS-446D sufficient to establish
compliance with the technical standards of the applicable rule part(s).
This includes, but is not limited to, the following items required under FCC Part 2.1033(c):
(2) FCC Identifier.
(3) A copy of the installation and operating instructions.
(4) Type of emission.
(5) Frequency range.
(6) Range of operating power, and means to provide variation in operating power.
(7) Maximum power rating.
(8) DC voltage chart.
(9) Tune-up procedure.
(10) A description of all frequency determining and stabilization circuits. A description of the circuits
used to suppress spurious radiation, limiting modulation, and limiting power.
(12) Drawing with labels for controls and complete circuit diagrams.
Signed:
Michael A. Pickard - Project Engineer

TWO-WAY RADIO BY RITRON
RITRON MODEL PBS-446D
UHF FM BAND PROGRAMMABLE BASE RADIO
MAINTENANCE / REPAIR / OPERATING MANUAL
FOR USE BY AUTHORIZED SERVICE/MAINTENANCE PERSONNEL ONLY
PBS-446D-MRM REV A
COPYRIGHT2002 RITRON, INC. •ALL RIGHTS RESERVED
RITRON, JOBCOM, and QUIET CALL, ARE REGISTERED TRADEMARKS OF RITRON, INC.

TABLE OF CONTENTS PBS-446D
TOPIC PAGE
IMPORTANT MAINTENANCE/REPAIR INFORMATION .. 1
SPECIFICATIONS
GENERAL......................................................................... 2
CONTROLS ...................................................................... 2
TRANSMITTER................................................................. 3
RECEIVER........................................................................ 3
BATTERY ......................................................................... 3
INTRODUCTION
GENERAL......................................................................... 4
Model Identification ..................................................... 4
FCC REGULATIONS
Licensing..................................................................... 4
How to Obtain an FCC Radio License......................... 4
EXPOSURE TO RADIO FREQUENCY ENERGY ............. 4
OPERATION
DESCRIPTION OF CONTROLS AND CONNECTORS..... 5
Fig. 3 Controls and Accessory Connectors.................. 5
BASIC RADIO OPERATION
On-Off/Volume Adjust ................................................. 6
Channel Selection ....................................................... 6
Receive....................................................................... 6
•Carrier Squelch....................................................... 6
•Tone Squelch ......................................................... 6
•No Squelch............................................................. 6
•2-Tone Paging ........................................................ 6
QC and DQC Tone Codes........................................... 6
Transmit...................................................................... 7
Battery Saver .............................................................. 7
SCAN CHANNEL OPERATION ........................................ 7
How Scanning Works.................................................. 7
Temporary Busy Channel Blocking ............................. 7
Last Channel Scanned Alert Tone............................... 7
Priority Scanning (Optional)......................................... 7
2-TONE PAGING OPERATION ........................................ 7
WHAT THE RADIO TONES MEAN
Power On/Self Check “OK........................................... 8
Error Tones ................................................................. 8
Channel Select............................................................ 8
Scan Channel.............................................................. 8
Squelch Mode ............................................................. 8
Transmitter Time Out .................................................. 8
Battery Alert Tone ....................................................... 8
OPTIONAL RADIO TONES
Courtesy Beep ............................................................ 8
Busy Channel TX Inhibit.............................................. 8
Transmitter Clear To Talk Beep .................................. 8
TROUBLESHOOTING
General ....................................................................... 9
Error Tones ................................................................. 9
Tone Coded Squelch................................................... 9
PROGRAMMING THE RADIO
PROGRAMMING METHODS.......................................... 10
FIELD PROGRAMMING
Fig. 4 Placing the Radio in Program / Readout Mode 10
How to Readout Field Programmed Frequency
and Tone Codes........................................................ 10
How to Field Program Frequency & Tone Codes ...... 11
PTT Programming Mistakes...................................... 11
How to Delete a Channel........................................... 12
How to Turn Channel Scan On / Off .......................... 12
Table 1 – PTT Programming Frequency Table.......... 13
Table 2 – Quiet Call Codes and Frequencies ............ 13
COMPUTER SOFTWARE COPYRIGHTS ...................... 13
PC COMPUTER PROGRAMMING ................................. 13
TOPIC PAGE
Programmable Features ............................................14
Descriptions of Features............................................ 14
2-Tone Paging Options.............................................. 15
Scan Channel Options............................................... 15
THEORY OF OPERATION
INTRODUCTION .............................................................16
POWER SUPPLY AND VOLTAGE DISTRIBUTION........ 16
Power Strobe............................................................. 16
Low Battery Voltage Detection...................................16
REFERENCE OSCILLATOR ........................................... 16
SYNTHESIZER ..............................................................16
Pin Numbers.............................................................. 16
Prescaler Divider / Synthesizer Controller..................17
VCO / Buffer Amplifiers .............................................17
Oscillator Modulation .................................................17
DIGITAL POTENTIOMETERS......................................... 17
RECEIVER ......................................................................17
RF Amplifier...............................................................17
1st Mixer.................................................................... 17
FM Receiver Subsystem............................................ 18
Voice / Tone Conditioning in Receiver Mode .............18
Voice Band ................................................................ 18
Sub-Audible............................................................... 18
Audio Amplifier ..........................................................18
ANTENNA SWITCHING / LOW-PASS FILTER............... 18
TRANSMITTER ............................................................... 19
Keying .......................................................................19
+VTX Supply..............................................................19
Power Amplifier .........................................................19
Voice/Tone Conditioning in Transmit Mode ...............19
AGC Microphone Amplifier ........................................ 19
Voice Band ................................................................ 19
Sub-Audible............................................................... 19
CHANNEL DISPLAY .......................................................19
MICROCONTROLLER ....................................................20
ALIGNMENT PROCEDURE
RECOMMENDED TEST EQUIPMENT............................21
RADIO PREPARATION...................................................21
REFERENCE FREQUENCY ...........................................21
MODULATION BALANCE ...............................................21
TRANSMITTER TONE DEVIATION ................................22
TRANSMITTER VOICE DEVIATION............................... 22
RECEIVER SENSITIVITY ............................................... 22
RECEIVER NOISE SQUELCH ........................................ 22
SYNTHESIZER ...............................................................23
VOLTAGE CHART
Measurement Conditions................................................. 24
PBS-446D Voltages.........................................................24
CASE ASSEMBLY PARTS LIST.....................................27
SCHEMATIC AND PART PLACEMENT DRAWINGS
TOP SIDE PART PLACEMENT.......................................28
BOTTOM SIDE PART PLACEMENT...............................29
SCHEMATIC – UHF RF ..................................................30
SCHEMATIC – Signal Processing ...................................31
SCHEMATIC – Microcontroller ........................................32

IMPORTANT REPAIR / MAINTENANCE INFORMATION PBS-446D
1
Surface Mount Repair
RITRON surface mount products require special
equipment and servicing techniques. Improper
servicing techniques can cause permanent damage
to the printed circuit boards and/or components,
which is not covered by RITRON’s warranty. If you
are not completely familiar with surface mounted
component repair techniques, RITRON recommends
that you defer maintenance to qualified service
personnel.
Precautions for Handling CMOS Devices
This radio contains complementary metal-oxide
semiconductor (CMOS) devices, which require
special handling techniques. CMOS circuits are
susceptible to damage by electrostatic or high voltage
charges. Damage can be latent, with no failure
appearing until weeks or months later. For this
reason, take special precautions any time you
disassemble the radio. Follow the precautions below,
which are even more critical in low humidity
environments.
1) Storage/transport - CMOS devices that will be
stored or transported must be placed in
conductive material so that all exposed leads are
shorted together. CMOS devices must not be
inserted into conventional plastic “snow” or
plastic trays of the type that are used for other
semiconductors.
2) Grounding - All CMOS devices must be placed
on a grounded bench surface. The technician
that will work on the radio/CMOS circuit must be
grounded before handling the radio. Normally,
the technician wears a conductive wrist strap in
series with a 100K Ohm resistor to ground.
3) Clothing - Do not wear nylon clothing while
handling CMOS circuits.
4) Power off - Remove power before connecting,
removing or soldering a PC board that contains
CMOS devices.
5) Power/voltage transients - Do not insert or
remove CMOS devices with power applied.
Check all power supplies to be used for testing
CMOS devices, making sure that no voltage
transients are present.
6) Soldering - Use a grounded soldering iron for
soldering CMOS circuitry.
7) Lead-straightening tools - When straightening
CMOS leads, provide ground straps for the tool
used.
PC Board Removal - Special Tool
RITRON recommends using a knurled nut tool to
remove the slotted knurled nuts that secure the
charge and audio jacks on top of the radio. You will
need two sizes of this tool, one for each jack size.
Mouser Corporation is one source, stock number
382-0004 (2.5mm jack) and 382-0006 (3.5mm jack).
You can reach Mouser sales and distribution center
at 1-800-346-6873.
Properly Attach the Synthesizer Shield
The synthesizer shield should not be removed, unless
a component must be replaced. This shield is
soldered to the main PC board.
Re-assembly - Speaker Magnet, Battery Voltage
on Connector Pin
The speaker magnet will pick up clipped leads and
other small metal objects from your bench top. Even
tiny objects on the diaphragm will cause the speaker
to buzz. Make sure the speaker is free of foreign
objects before reassembling the radio.
Radio Transmitter Power Measurements
The PBS-446D was designed to produce a maximum
of 2.5 Watts of Transmitter power throughout the
radio’s operating frequency range. The transmitter
was designed with close tolerances to prevent RF
power output from exceeding specifications.
PCB and Firmware Revisions
Changes in circuit design, component values, and
radio firmware are made occasionally to enhance the
performance of the PBS-446D. In general, the
manual will be periodically updated for component
value changes without a change in the manual
revision level. Always refer to the Schematic for the
most recent component values. Changes in circuit
design that require printed circuit board revision, or
changes in firmware that significantly alter the
operating characteristics of the radio, will be covered
in a revised manual.
This manual is updated for the following revisions:
PBS-446D-MRM Rev A
PCB Revision 1750330B
Firmware Revision v6.06

SPECIFICATIONS PBS-446D
2
GENERAL
FCC ID: AIERIT16-446
FCC Rule Parts: 90, 90.210
Frequency Range: 450 to 470 MHz
Max. Freq. Separation: 20 MHz
RF Channels: Up to 10 Channels,
Independent TX/RX
frequencies.
Synthesizer Step Size: 12.5 KHz
Frequency Stability: +/-2.5 PPM (-30 to +60 C)
TX/RX
Tone/Code Signaling: CTCSS (Quiet Call)
Digital Coded Squelch
(Digital Quiet Call)
2-Tone Paging Decode
Dimensions: 1.5”H x 3.75”W x 6.0”D
Weight: 1 lb. 5 oz. with antenna
Enclosure Material: Steel with e-coat finish
Environmental: Splash resistant and
shock and vibration per
RITRON Drop Test (6 ft.
drop onto concrete on all
six sides)
Antenna Fitting:BNC
Earphone Jack: 3.5 mm, disconnects the
internal speaker for
external earphone,
speaker / microphone, or
headset. Also provides
cable connection for PC
programming.
Microphone/PTT 2.5 mm, for external
Speaker / microphone or
headset.
CONTROLS
Push Button Controls: On/Volume Up, Volume
Down/Off, PTT, Channel,
Special Feature “Z”
Speaker Beep Indicators:
On/Volume Up: Radio emits channel beep
when turned on, followed
by increasing audio to
adjust volume.
Volume Down/Off: Decreasing audio to adjust
volume, with two tones
when turned off.
Both Volume Buttons: Alternates between Tone
Squelch (single beep) and
Carrier Squelch (two
beeps).
On channels programmed
for 2-tone paging decode,
three beeps indicates 2-
tone paging is set.
If both buttons are held
down until the radio beeps
repeatedly, squelch will be
disabled.
PTT: Programmable for a single
“transmit beep”.
Channel: Programmable for a
Channel beep whenever
the channel is changed.
When the scan channel is
selected the radio emits a
Scan beep.
Channel Display: The 7-segment LED
display indicates current
operating channel. When
the scan channel is
selected the display will
rapidly flash the channels
as they are scanned, and
will stop when a channel is
received.
Transmit/Monitor Lamp: A single light in the lower
right corner of the channel
display is used as a
transmit indicator and as a
receive carrier indicator.

SPECIFICATIONS PBS-446D
3
TRANSMITTER
RF Power Output: 2.5 Watts @ +13 VDC
Wide Mode Narrow Mode
Emission Designator: 16K0F3E 11K0F3E
Deviation: +/- 5.00 KHz +/- 2.50 KHz
FM Hum and Noise: -40 dB -37 dB
Audio Distortion:< 2 % < 6 %
Spurious & Harmonics: -55 dBc
Audio Response: Meets FCC and EIA
requirements
Time-out Timer: 60 seconds,
programmable
RECEIVER
Wide band Narrow band
Models Models
Modulation Acceptance: +/- 7.0 KHz +/- 3.75 KHz
Sensitivity: 0.25 µV 0.25 µV
(12 dB SINAD)
Adjacent Channel (EIA): -65 dB -50 dB
Spurious Rejection: -60 dB -60 dB
Image Rejection (EIA): -65 dB -65 dB
Intermodulation (EIA): -65 dB -65 dB
Noise Squelch Programmable per
Sensitivity: channel, factory set for 12
dB SINAD
Frequency Response: 300 - 3000 Hz, de-
emphasized
Audio Output 1 Watt into 8 Ω, with less
than 5 % THD @ the
earphone jack
Receiving System: Dual conversion
superheterodyne
I.F. System: 1st - 43.65 MHz,
2nd - 450 KHz
L.O. Injection: Low side
QC/DQC Decode Time: per EIA Standards
BATTERY
Battery Drain at 12 VDC:
Standby: 71 mA
Sleep: 25 mA
Avg. Standby
with Power Saver: 28.5 mA
Receive: 250 mA
Transmit: 700 mA @ 2.5 Watts

INTRODUCTION PBS-446D
4
GENERAL
RITRON's PBS-446D base station is a small,
programmable two-way radio, designed to operate in
the 450-470 MHz professional FM communications
band. The base station features push-button
operating controls conveniently located on the top
face of the radio. A display on the front of the base
station case indicates the current operating channel
and contains a indicator lamp used as a transmit
indicator and as a receive carrier indicator.
Each radio can be “dealer” programmed to contain a
unique set of operating frequencies and options.
Selective signaling options include Quiet Call
(CTCSS), Digital Quiet Call (DCS) and 2-tone
sequential paging decode. Transmitter power,
operating bandwidth and battery saver are among the
options programmable on a per channel basis.
Model Identification
The PBS-446D model, serial number and FCC
Identification are displayed on a label located on the
bottom of the radio.
FCC REGULATIONS
Licensing
The FCC requires the radio owner to obtain a station
license for his radios before using them to transmit,
but does not require an operating license or permit.
The station licensee is responsible for ensuring that
transmitter power; frequency and deviation are within
the limits specified by the station license. The station
licensee is also responsible for proper operation and
maintenance of the radio equipment. This includes
checking the transmitter frequency and deviation
periodically, using appropriate methods.
How to Obtain an FCC Radio License
Make application for your FCC license on FCC Forms
600 and 159.
To have forms and instructions faxed to you by the
FCC, call the FCC Fax-On-Demand system at 202-
418-0177 from your fax machine; request Document
000600 and Form 159.
To have Document 000600 & Form 159 mailed to
you, call the FCC Forms Hotline at 800-418-3676.
For help with questions concerning the license
application, contact the FCC at 888-225-5322.
EXPOSURE TO RADIO FREQUENCY ENERGY
The PBS “D-Series” base radios generate
electromagnetic energy during transmit mode. This
product has been evaluated for compliance with the
maximum permissible exposure limits for RF energy
at the maximum power rating of the unit with the
antenna included with the unit. To comply with
Occupational/Controlled limits, all persons must be at
least 5.7 inches from the antenna while the unit is
transmitting. Other antenna may require lesser or
greater distances to meet limits depending upon their
gain relative to that tested. Higher gain antennas are
capable of yielding a higher RF energy density in the
strongest part of their field and would, therefore,
require a greater separation from the antenna. This
product is not designed to be used by the general
public in an uncontrolled environment unless
compliance with the Uncontrolled/General Population
limits for RF exposure can be assured.
To ensure that exposure to RF electromagnetic
energy is within thew allowable limits for occupational
use, always adhere to the following guidlines:
•Use only the antenna(s) available from RITRON
for this model. DO NOT operate the radio without
an antenna.
•Keep talk times as short and infrequent as
possible. DO NOT depress the PTT button when
not actually wishing to transmit. The radio is
equipped with an internal timer to limit
continuous transmit times.
•When transmitting, maintain a distance of at
least 5.7 inches. DO NOT hold the radio in such
a manner that the antenna is next to, or touching,
exposed parts of the body, especially the face or
eyes while transmitting.
•DO NOT allow children to operate the radio.
When used as directed, this series of radios is
designed to comply with the FCC’s RF exposure
limits for “Occupational Use Only”. In addition, they
are designed to comply with the following Standards
and Guidelines:
• FCC OET Bulletin 65, Edition 97-01, Supplement
C, Evaluating Compliance with FCC Guidelines for
Human Exposure to Radio Frequency
Electromagnetic Fields.
• American National Standards Institute (C95.1-
1992), IEEE Standard for Safety Levels with
Respect to Human Exposure to Radio Frequency
Electromagnetic Fields, 3 kHz to 300 GHz.
• American National Standards Institute (C95.3-
1992), IEEE Recommended Practice for the
Measurement of Potentially Hazardous
Electromagnetic Fields-RF and Microwave.

OPERATION PBS-446D
5
DESCRIPTION OF CONTROLS AND
CONNECTORS
Channel Display
The channel display will indicate the current
operating channel. When the Scan Channel is
selected the display will rapidly flash the
channels being scanned, and will stop when a
channel is received.
Channel Selector
Press the button and the radio will emit the
channel beep, advance the channel, and the
channel display will show the new operating
channel. When the Scan Channel is selected
the radio will emit the Resume Scan Beep and
the radio will begin scanning.
Audio Accessory Jack
The audio accessory jack is used to plug in
earphone options, and, in conjunction with the
charge jack, to connect an optional remote
speaker/ microphone or a single- or dual-ear
headset. This jack is also used for PC
programming.
Microphone Jack
The microphone jack is used to connect optional
external microphones and, in conjunction with
the audio accessory jack, to connect an optional
remote speaker/ microphone or a single- or dual-
ear headset.
Microphone
The microphone allows your voice to be heard in
transmissions to other radios. Speak in a normal
tone; shouting does not improve your listener's
reception.
Power Connector (top end of case)
The power connector on the top end of the radio is used to
connect power to the unit, either an external 12 VDC supply or
the RPS-1A wall-mounted power supply included with the
radio.
Speaker
The speaker, located behind the front grille, allows you to hear
calls on your channel.
Antenna
The flexible antenna radiates and receives radio signals. The
antenna connects to a BNC type connector located on the top
end of the radio.
NOTE:The AFB-1545 antenna furnished with the radio is dual
band, and will work with VHF and UHF radios.
Special Feature "Z" Button
The Special Feature "Z" button can be PC programmed for
many unique functions such as Scan, Weather Channel, send
DTMF ANI, send 2-Tone Page, Monitor, 2-Tone reset,
Transpond, or Emergency.
Volume Down/ Off
Press the Volume Down/Off button to decrease volume. To
switch Off the unit, press and hold this button until the speaker
emits a double beep.
On/ Volume Up
To switch the unit On, press the On/Volume Up button; the
speaker will emit a turn on beep. If the radio turns on to the
Scan Channel it will emit the Resume Scan Beep. Once the
radio is On, press this button to increase volume.
Push-to-Talk Switch (PTT)
Press and hold the PTT when transmitting; release it to
receive.
Fig. 3 Controls and Accessory Connectors
Channel Display
Channel Selector
Audio Accessory Jack
Mi
c
r
op
h
o
n
e
Jac
k
Antenna
Special Feature “Z”
Volume Down/ Off
On/ Volume Up
Push-To-Talk
Microphone

OPERATION PBS-446D
6
BASIC RADIO OPERATION
On-Off / Volume Adjust
To switch on the radio - press the On/Volume Up
button. The radio will emit the Channel beep. If the
radio turns on to the Scan Channel it will emit the
Scan Beep. The radio will turn on to the channel that
was selected when it was last turned off, or can be
programmed to always turn on to channel 1.
To adjust the volume - press the volume up or the
volume down button until you reach the desired level.
You should hear noise or any broadcasts on the
channel.
To turn off the radio - press and hold the Off/Volume
Down button until a two tone "turn-off" beep is heard.
For instant turn-off, press the PTT button while
holding the Off/Volume Down button.
Channel Selection
To change channels - press and release the Channel
Selector button. The radio will emit a short Channel
beep, increment the channel, and the Channel
Display will show the new operating channel. If the
highest channel number is selected and you press
the Channel Selector button, the radio resets to
channel 1 and the Channel beep is heard on the
speaker.
If the Scan Channel is selected - the radio will emit
the Scan Beep and the Channel Display will rapidly
flash the channel numbers as they are scanned. If a
signal is received the channel display will indicate the
channel number, and when the received signal is
removed the radio will wait briefly, sound the Scan
Beep, then scanning will resume as normal.
If the Weather Channel is selected - on a VHF radio
the Channel beep will be heard and the display will
light a single segment that indicates which of the
seven NOAA frequencies is monitored. See the
"NOAA Weather Radio" section on page 7 for details.
Receive
To hear calls from other users - adjust the volume as
desired. The radio can receive broadcasts while the
Push-To-Talk button is not being pressed. Whether
or not you hear these broadcasts depends upon the
squelch settings.
There are four squelch modes that can be used in the
PBS "D-Series" base radio.
•Carrier squelch lets you hear all broadcasts on
your channel strong enough for the radio to
detect, and silences noise.
•Tone squelch uses one of the QC or DQC “tone
squelch” formats available on the PBS. This
allows you to screen out “on-channel” broadcasts
that do not carry the correct code programmed for
the radio.
•No squelch disables all squelch operation and
allows you to hear even the weakest broadcasts
on your channel.
•2-tone paging can be used in conjunction with
either carrier or tone squelch to block out all calls
except those sent specifically to your radio. When
the unique 2-tone sequence programmed into the
radio is decoded, the radio will emit a series of
ring tones similar to a telephone.
Once a squelch type has been selected by the user,
all channels will operate in that mode. The PBS "D-
Series" radio will operate in tone squelch mode when
it is 1st turned on.
To monitor the channel - press one of the volume
control buttons. When you press the volume up or
the volume down button, squelch turns off and all
radio traffic on the channel (or noise) sounds in the
speaker.
To activate carrier squelch - simultaneously press
both of the volume buttons and hold briefly before
releasing. When carrier squelch is on, the radio
emits a “double beep.” The radio will now let you
hear all broadcasts on your channel.
To activate tone squelch - simultaneously press both
of the volume buttons and hold briefly before
releasing. When tone squelch is turned on, the
handheld sounds one beep. You will only hear
broadcasts that carry the same QC or DQC code
programmed into your radio.
To activate no squelch - simultaneously press both of
the volume buttons and continue to hold them down.
About 3 seconds after the beep (or double beep), the
radio will start beeping repeatedly. This means that
squelch is turned off. Release the buttons. To
restore squelch, press and hold both of the volume
buttons until the radio sounds a beep or double beep.
If you are unable to activate carrier or no squelch the
radio has been optionally programming for Monitor
Lockout. See your Ritron dealer or contact Ritron
directly to disable this option.
To activate 2-tone paging - simultaneously press both
of the volume buttons and hold briefly before
releasing. When 2-tone paging is turned on, the
handheld sounds a "triple beep". You will only hear
broadcasts that first send your two unique paging
tone. If you are unable to set the radio, you have
selected a channel that is not programmed for 2-tone
paging decode.
Using the "Z" button for squelch - The PBS base
radio "Z" button can be programmed to monitor,
toggle tone/carrier squelch, or reset 2-tone paging.
Note: It is possible that the beginning of a call might
be missed while the radio is in battery saver mode. If
this happens, ask the caller to repeat the message.
QC and DQC Tone Codes
Tone codes filter out static, noise and reduce
unwanted "chatter" on radio channels. When you
operate on a frequency with a tone code, you screen
out most interference. This allows you to
communicate with less interference and to hear only
those users in your radio group.
IMPORTANT! All radios in the talk group must
operate on the same frequency and tone code.

OPERATION PBS-446D
7
Transmit
Normally, you should not transmit until no one is
talking on the channel. This can be determined by
monitoring the channel prior to transmitting.
To transmit - hold down the Push-To-Talk button and
with the radio at least 6 inches away talk into the
microphone. Speak in a normal tone, since talking
louder will not improve the listener’s reception.
Keep talk times as short and infrequent as possible to
allow others to use the channel.
Battery Saver
The base station has a programmable "battery saver"
feature that conserves battery power. This feature is
disabled with normal operation using the RPS-1A
power supply. The battery saver constantly checks
the radio's transmitter, receiver and controls for
activity. If a number of seconds pass without the
receiver detecting a call, and without the user
operating a control, this feature removes power from
most of the radio.
During this "off-time," any activity restores full power.
Every few fractions of a second, the battery saver
applies power to the receiver, checking for
broadcasts. It is possible that the first part of an
incoming call might go unheard before activity is
detected and power restored. If this happens, the
caller can repeat his message. Once "radio contact"
is made, normal unhurried conversation can follow.
SCAN CHANNEL OPERATION
Channel scanning allows you to listen to broadcasts
on your radio channels. The PBS "D-Series" base
radio will scan all channels programmed into the
radio except the NOAA Weather Channel.
How Scanning Works
Using the Channel Selector button, select the Scan
Channel. The radio sounds the Scan Beep, and then
repeatedly checks each channel in the scan list. The
channel display will show the channel numbers as
they are scanned. The "Z" button can also be
programmed to initiate scanning.
When receiving a call on a channel being scanned,
the radio will stop scanning to let you hear
communications on that channel. After the
transmission has ended the radio will pause before it
resumes scanning to allow you time to respond.
When transmitting from the Scan Channel, the radio
will go to the last channel on which a signal was
received, then transmit. After you release the PTT
the radio will pause to allow time for a response, and
then resume scanning.
Temporary Busy Channel Blocking
If one of the channels in the scan list is so busy that
you want to temporarily block it out, press the
Channel Selector button while the radio is stopped on
the channel to be blocked and hold it until scanning
resumes. The blocked channel will now be skipped in
the scan list.
The blocked channel will be returned to the scan list if
the radio is turned off, or when the radio channel is
changed using the Channel Selector button. The 1st
channel in the scan list cannot be blocked.
Last Channel Scanned Alert Tone
When changing channels with the Channel Selector
button, an alert tone will sound to indicate the last
channel that received a message when the radio was
scanning. This will identify the channel on which the
last message was received, and allow uninterrupted
transmission on that channel without the constraints
of scanning. You can then press the Channel
Selector button to return to the scan channel.
Priority Scanning (Optional)
The PBS "D-Series" base radio can be optionally
programmed for priority scanning. Priority Scan
allows you to periodically monitor a Priority Channel,
even if the radio has stopped on another channel.
This will prevent missed calls on the primary
operating channel when in scan mode.
With Priority Scan enabled:
• The first channel in the scan list is the Priority
Channel.
• The radio checks the Priority Channel every two
seconds to check for activity. This time is
programmable and can be set for 1 - 8 seconds.
• The radio can be programmed to transmit only on
the Priority Channel when scanning.
• The radio can be programmed to sound a Priority
Channel Beep whenever the radio receives on the
Priority Channel when scanning.
See your Ritron dealer or contact Ritron directly for
PC programming of this option.
2-TONE PAGING OPERATION
To use 2-tone paging the PBS "D-Series" base
radio must be PC programmed for this option, the
radio does not operate with 2-tone decoding as it is
received from the factory. See your Ritron dealer or
contact Ritron directly for PC programming of this
option.
To activate 2-tone paging you must first select a radio
channel that has been PC programmed for 2-tone
paging decode. The radio is normally programmed to
automatically activate 2-tone decode any time the
paging channel is selected. If not, simultaneously
press both of the volume buttons and hold briefly
before releasing. The handheld sounds three beeps
when 2-tone paging is turned on. The "Z" button may
also be programmed for 2-tone paging reset. If you
are unable to set the radio, you have selected a
channel that is not programmed for 2-tone paging
decode.

OPERATION PBS-446D
8
When receiving a 2-tone page the radio will emit a
"ring" tone similar to a telephone and the display will
show a "C" to indicate that a call has been received.
You can now proceed with normal two way
communication until 2-tone paging has been reset.
The "ring" tone will sound every time a 2-tone page is
decoded.
To reset 2-tone paging after receiving a call,
simultaneously press both of the volume buttons and
hold briefly before releasing. The handheld sounds
three beeps when 2-tone paging is reset and the
display will show the channel number. The radio can
be optionally programmed to automatically reset if a
call is not answered within 15 seconds, or the "Z"
button can be programmed for 2-tone paging reset.
2-tone paging channels can be optionally
programmed to:
• Automatically set the radio for 2-tone paging
mode whenever the channel is selected.
• Automatically reset if a 2-tone page is not
answered within 15 seconds.
• Automatically place the receiver into carrier
squelch "monitor" mode whenever a 2-tone page
has been decoded.
• Transmit a transpond tone to let the paging
station know that the page has been received.
• Decode an All Call tone.
• Decode a Group Call if the 1st tone is sent for an
extended period of time.
WHAT THE RADIO ALERT TONES MEAN
The radio responds to certain instructions by
sounding a beep or series of tones. These tones can
tell you that the radio is working as you expect.
Power On/Self Check “OK”
When it is first turned on, the radio runs a quick “self
test” to confirm basic functions. When complete the
radio will emit the channel beep and the Channel
Display will show the operating channel. The radio is
then ready to use.
Error Tones
However, if the “self test” detects a diagnostic error,
an error tone sounds. The error tone indicates the
radio frequency synthesizer is malfunctioning. Turn
off the radio and try again. The error tone will also
sound if a channel has been programmed for an
invalid frequency. A long, low-pitched tone means
the battery voltage is too low to operate the radio. If
you cannot correct a problem, consult an authorized
Ritron service facility or Ritron.
Channel Select
When the Channel button is pressed, the radio will
emit a short channel beep, increment the channel,
and the channel display will show the new operating
channel.
Scan Channel
When the Scan channel is selected by pressing the
Channel button, the radio will emit the Scan beep and
begin scanning.
Squelch Mode
When you press and hold both Volume buttons at the
same time, a single beep will sound to indicate that
tone squelch is on. A “double beep” means that
carrier squelch is on. If the channel is programmed
for 2-tone paging, a "triple beep" indicates that the
pager has been reset.
Transmitter Time Out
A low tone followed by a higher-pitched tone sounds
and the transmitter automatically shuts off if you hold
down the PTT button longer than 60 seconds. The
radio automatically switches to receive mode.
Battery Alert Tone
In battery powered installations, as the battery
voltage approaches the minimum required "operating
voltage" the radio will sound a short beep every 20
seconds to alert the user that the battery will soon
need recharge or replacement. Once the battery
voltage drops below the required "operating voltage"
the radio emits a long, low tone and turns itself off.
OPTIONAL RADIO ALERT TONES
The PBS "D-Series" base radio can be programmed
using the RITRON PC Programmer for optional alert
tones. See your Ritron dealer or contact Ritron
directly for programming of these options.
Courtesy Beep
A short tone sounds at the end of each received
transmission to indicate that the channel is clear and
you may transmit.
Busy Channel TX Inhibit
If a user is transmitting on your radio frequency
without your tone, you will not be allowed to transmit.
The radio will beep a series of long, low tones while
the PTT is held down (like a busy signal).
Transmit Clear To Talk Beep
A short tone sounds after the PTT has been pressed
to indicate that the radio is ready for you to begin
talking.

OPERATION PBS-446D
9
TROUBLESHOOTING
If you have trouble operating the base station, review
the radio controls and operation sections. If you think
the radio is malfunctioning, check the following table.
GENERAL
Operating features do not work exactly as expected.
•The radio has been factory or dealer
programmed for customized operation.
Reception is poor.
•Move to a different location. (Note 2.)
•Confirm that the proper antenna is connected to
the radio. (See p. 7, "Antenna.")
You cannot hear calls from other radios.
•Turn off tone squelch. (See Note 3.)
•Be certain your radio receives on the same as
the caller transmits. (Note 4.)
Your calls cannot be heard in other radios.
•Make sure that your radio transmits on the
receive frequency of the radio(s) you want to call.
(Note 4.)
TONE CODED SQUELCH
You cannot screen out calls from users outside of
your tone group.
•Make sure the channel is programmed with tone
squelch.
•Activate Tone (coded) squelch. (Note 7.)
You cannot hear Tone coded messages while in
Tone (coded) squelch.
•Confirm that the channel is programmed to
detect the same code as the calling radio(s)
transmits. (Note 7.)
Others in your tone group cannot hear your tone
coded messages.
•Verify that you transmit the same code as the
radio(s) you call are programmed to detect.
(Note 7.)
ERROR TONES
An error tone sounds when the radio is first
turned on.
•See "Error Tones" in the Operation section.
An error tone sounds while you are talking. (and
the transmitter shuts off).
•Refer to “Error Tones”
Notes
1.
2. Reception can often be improved by moving a
short distance. This effect is more noticeable
inside of buildings. The range of these base
stations equipped with a standard battery pack is
about two miles (line-of-sight).
3. If your radio does not detect calls from other
radios on the channel, turn off tone squelch.
(Press both Volume buttons at the same time - a
double beep means that tone squelch is off.)
4. If you want to hear a call, you must select a
channel that is programmed to receive the
caller’s transmit frequency. If you want to call
another unit, you must select a channel that is
programmed to transmit the other radio’s receive
frequency. However, if you use a repeater, your
channel must be programmed to work with the
repeater’s transmit and receive frequencies. (A
radio channel can hold two separate operating
frequencies, one for Receive, the other for
Transmit.)
5. Maximum power drain occurs while the radio
transmits, so don’t hold down the Push-To-Talk
button more than necessary. Battery power is
used while the base station is left on to receive
calls. If practical, switch off the unit.
6.
7. In order for radios to communicate using Quiet
Call, they must be programmed with the same
tone code. Each code is unique, and your radio
will respond only to the code programmed.
Press and hold both volume buttons at the same
time. A single beep means that tone squelch is
on. A double beep means that tone squelch is
off.

PROGRAMMING THE RADIO PBS-446D
10
PROGRAMMING METHODS
Each PBS-446D can be programmed to operate on
up to 10 channels. The PBS-446D may be
programmed using the Push-to-Talk switch or an
optional RITRON PC programming kit.
FIELD PROGRAMMING allows you to program any
channel to one of the radio frequencies listed in Table
1 and any Quiet Call code listed in Table 2. The radio
will transmit and receive on the programmed table
frequency and QC code.
PC PROGRAMMING allows you to program any
frequency within the band and channel spacing of the
radio model. This method also lets you customize the
base station with optional operating features.
FIELD PROGRAMMING
Note: If the radio will not enter program / readout
mode, this feature has been turned off using the
optional PC programming kit.
How to Readout Field Programmed Frequency
and Tone Codes
In our example a UHF radio is programmed for
channel 3 to operate on the "Brown Dot" frequency of
464.500 MHz with 100.0 Hz tone.
1. To enter the Program / Readout Mode,
refer to FIG-4. A "P" will appear on the
channel display as you enter program
mode.
2. Press the Channel Selector button to
select the channel to be read out. The
channel number will appear briefly on
the display as you step through the
channels.
3. When you have settled on a channel a
hyphen will appear across the center
of the display to indicate that it is ready
for readout.
4. Press and release the On/ Volume Up
button. The radio will display a series
of four digits; with each digit separated
by a hyphen.
5. Write down the four digits. The first two
digits indicate the frequency code and
the last two digits the tone code; see
Tables 1 and 2 on page 15.
6. The radio display will briefly show the
channel number, then a triple beep will
sound.
7. If the channel is PC-programmed with
any frequency or tone not listed in
Table 1or 2 on page 15, the radio will
sound the error tone on contents read
out and display an "E".
8. To read out another channel, follow
steps 2 through 6.
9. Turn the radio off.
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Fig. 4 Placing the Radio in PTT
Pro
g
ram / Readout Mode
2. Press & hold the
Push-to-Talk button.
1. Press & Hold until the
“Radio Off” tones are
heard
,
then release.
3. Press & release –
the radio will start
beeping rapidly.
4. Continue holding the
Push-to-Talk button until
the beeping stops, then
release it.
5. The radio will emit a triple
tone: it is now in
Program/Readout mode.

PROGRAMMING THE RADIO PBS-446D
11
How to Field Program Frequency & Tone Codes
To match other radios, the owner can select
Frequency and Tone Codes from Tables 1 and 2 on
page 15.
In our example we will program channel 3 of a UHF
radio to operate on the "Brown Dot" frequency of
464.500 MHz with 100.0 Hz tone.
1. Refer to Table 1 on page 15 to
determine the two-digit frequency
code and write it down.
2. Refer to Table 2 on page 15 to
determine the two-digit tone code for
100.0 Hz and write it down.
3. Follow the instructions in FIG-4 on
page 12 to place the radio in the
Program/ Readout Mode. A "P" will
appear on the channel display as you
enter program mode.
4. Press the Channel Selector button to
select the channel to be programmed.
The channel number will show briefly
on the channel display as you step
through the channels.
5. When you have settled on a channel
the display will show a hyphen across
the center to indicate that it is ready
for programming.
6. Enter the 1st digit of the frequency
code by clicking the PTT button until
the channel display shows the
desired number.
7. Pause—the radio will sound a low
tone and show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
8. Enter the 2nd digit of the frequency
code by clicking the PTT button until
the channel display shows the
desired number.
9. Pause—the radio sounds a low tone
and will show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
PTT Programming Mistakes
Invalid Entries
An error tone means that you tried to save an invalid
entry. No programming changes are made in this
case. A triple tone will sound next indicating that the
radio is still in programming mode, and ready for an
entry.
10.Enter the 1st digit of the tone code by
clicking the PTT button until the
channel display shows the desired
number.
11.Pause—the radio sounds a low tone
and will show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
12.Enter the 2nd digit of the tone code by
clicking the PTT button until the
channel display shows the desired
number.
13.Pause—the radio sounds a low tone
and will show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
14.Press and release the On/ Volume Up
to save your programming. The radio
display will briefly show the channel
number, then a triple beep will sound
to indicate that programming was
successful.
NOTE: An error tone will sound if you
attempt to save an incorrect code and
an "E" will appear on the display. Turn
the radio OFF, check the digits you are
attempting to enter, then start over.
15.To program another channel, repeat
steps 3 through 5.
16.Turn the radio OFF and then ON
again—the radio is now ready to use.
NOTES:
a. YOU MUST enter "44" to enter "No Code"
interference eliminator to match radios not
having tone codes. Refer to Table 2 on page 7.
b. If the radio does not sound a confirming triple
tone when you attempt to enter Program/
Readout Mode, the radio was factory or dealer
customized to disable programming. Consult the
radio owner or your dealer.
PTT Entry Mistakes
If you press the PTT five times when you intended
four, for example, or if you just lose count, do not
press the Volume Up button to store the entry.
Instead, start over by turning the radio off and placing
the radio in programming mode again.
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PROGRAMMING THE RADIO PBS-446D
12
How to Delete a Channel
In our example we will delete channel 3.
1. Follow the instructions in FIG-4 on
page 12 to place the radio in the
Program/ Readout Mode. A "P" will
appear on the channel display as you
enter program mode.
2. Press the Channel Selector button to
select the channel to be deleted. The
channel number will show briefly on
the channel display as you step
through the channels.
3. When you have settled on a channel
the display will show a hyphen across
the center to indicate that it is ready
for deleting.
4. Enter the 1st digit of delete code
“0000” by clicking the PTT button until
the channel display shows “0”.
5. Pause—the radio will sound a low
tone and show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
6. Enter the 2nd digit of delete code
“0000” by clicking the PTT button until
the channel display shows “0”.
7. Pause—the radio will sound a low
tone and show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
8. Enter the 3rd digit of delete code
“0000” by clicking the PTT button until
the channel display shows “0”.
9. Pause—the radio will sound a low
tone and show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
10.Enter the 4th digit of delete code
“0000” by clicking the PTT button until
the channel display shows “0”.
11.Pause—the radio will sound a low
tone and show a hyphen across the
center of the display to indicate that it
is ready to accept the next digit.
12.Press and release the On/ Volume Up
to save your delete programming.
The radio display will briefly show the
channel number, then a triple beep
will sound to indicate that the channel
was successfully deleted.
13.To delete another channel, repeat
steps 2 through 12.
14. Turn the radio OFF and then ON again—the radio
is now ready to use.
15. The remaining channels are in the same
sequence and will retain their same channel
number. The Channel Selector will skip over the
deleted channel numbers.
NOTE: If all channels are deleted the radio will not
operate, instead it will turn on in Field Program mode
to allow entry of a valid frequency and tone code.
How to Turn Channel Scan On / Off
1. Follow the instructions in FIG-4 on
page 12 to place the radio in the
Program/ Readout Mode. A "P" will
appear on the channel display as you
enter program mode.
2. Enter code "1" to turn channel scan
on. Enter the code by clicking the
PTT button until the channel display
shows “1”.
3. Pause—the radio will sound a low
tone and show a hyphen across the
center of the display.
4. Press and release the On/ Volume Up
to save your programming. The radio
will sound a triple beep to confirm that
channel scan has been turned on.
5. Enter code "2" to turn channel scan
off. Enter the code by clicking the
PTT button until the channel display
shows “2”.
6. Pause—the radio will sound a low
tone and show a hyphen across the
center of the display.
7. Press and release the On/ Volume Up
to save your programming. The radio
will sound a triple beep to confirm that
channel scan has been turned off.
8. Turn the radio OFF and then ON
again—the radio is now ready to use.
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PROGRAMMING THE RADIO PBS-446D
13
Code Frequency Description
01 467.7625 J
02 467.8125 K
03 464.5500 Yellow Dot
04 464.5000 Brown Dot
05 467.8500 Silver Star
06 467.8750 Gold Star
07 467.9000 Red Star
08 467.9250 Blue Star
09 469.2625
10 462.5750 White Dot
11 462.6250 Black Dot
12 462.6750 Orange Dot
Table 1 – PTT Programming Frequency Table
QC Freq QC Freq
Code (Hz) Code (Hz)
01 67.0 27 167.9
02 71.9 28 173.8
03 74.4 29 179.9
04 77.0 30 186.2
05 79.7 31 192.8
06 82.5 32 203.5
07 85.4 33 210.7
08 88.5 34 218.1
09 91.5 35 225.7
10 94.8 36 233.6
11 97.4 37 241.8
12 100.0 38 250.3
13 103.5 39 69.4
14 107.2 40 159.8
15 110.9 41 165.5
16 114.8 42 171.3
17 118.8 43 177.3
18 123.0 44 No Tone
19 127.3 45 183.5
20 131.8 46 189.9
21 136.5 47 196.6
22 141.3 48 199.5
23 146.2 49 206.5
24 151.4 50 229.1
25 156.7 51 254.1
26 162.2
Table 2 – Quiet Call Codes and Frequencies
COMPUTER SOFTWARE COPYRIGHTS
The RITRON, Inc. products described in this manual
include copyrighted RITRON, inc. computer
programs. Laws in the United States and other
countries grant to RITRON, inc. certain exclusive
rights in its copyrighted computer programs, including
the exclusive right to distribute copies of the
programs, make reproductions of the programs, and
prepare derivative works based on the programs.
Accordingly, any computer programs contained in
RITRON, inc. products may not be copied or
reproduced in any manner without the express written
permission of RITRON.
The purchase of RITRON, inc. products does not
grant any license or rights under the copyrights or
other intellectual property of RITRON, inc., except for
the non-exclusive, royalty fee license to use that
arises in the sale of a product, or as addressed in a
written agreement between RITRON, inc. and the
purchaser of RITRON, inc. products.
PC COMPUTER PROGRAMMING
RITRON’s programming kit allows programming of
the PBS-446D model radios using a PC compatible
computer. An adapter cable connects the radio to a
computer’s serial communications port. Once the
cable is hooked up, the user inserts the diskette
provided into his computer’s floppy disk drive and
loads a software program.
This program transfers data between radio and
computer memory, and includes on-screen
instructions and help. Radio data may be saved to
the computer’s hard disk in order to program other
radios.
The PC Programming Kit Includes:
1) Ritron Transceiver programming software, which
is contained on 3.5" diskettes.
2) Installation instructions and a registration form.
3) Ritron PC to radio adapter cable, which is
terminated at one end with a DB-25F connector,
at the other end with a modular plug. The DB-25
plugs into the computer’s serial port.
4) An adapter for use with PBS-446D base stations.
This adapter mates the modular plug to a 3.5 mm
plug, for connection to the base station audio
jack.
The PC Programming Kit Requires:
A PC compatible computer with Windows 95 or later.
The computer must have an RS-232 serial port and a
minimum of 2MB available on the hard disk drive for
installation.

PROGRAMMING THE RADIO PBS-446D
14
Programmable Features
The following features may be programmed on a per
channel basis, or will affect all channels together.
Factory Per
Feature Range Setting Channel
Automatic Inactivity Y - N N -
Turn-off
Battery Saver Enable Y - N Y -
Battery Saver Off Time 0 – 8 1 -
(seconds)
Beep Volume Level F-C C -
(Fixed or Controlled)
Beep Fixed Level 0 – 100% 50% -
(percent of full volume)
Busy Channel TX Inhibit Y - N N √
Carrier Only, No Codes - - √
Channel Beep Y – N Y -
Channel Display Power Y - N N -
Saver
Digital Tone Invert RX Y - N N √
Digital Tone Invert TX Y - N N √
Digital Quiet Call (DCS) - - √
Disable Monitor Y - N N √
Number of Channels 0 – 10 4 -
Narrow Band Channel Y - N N √
Programming Password 8 chars none -
PTT Programming Y – N Y -
Enabled
Quiet Call (CTCSS) See Table 2 - √
Receive Squelch Tone Y - N N √
Scan Channel Y – N Y -
Squelch Tightener -2 to 5 0 √
TX Time-out Enabled Y – N Y -
TX Time-out Timer 0 – 255 60 -
(seconds)
Turn On To Medium Y - N Y -
Volume Level
2-Tone Paging Decode Y – N N √
Descriptions of Features
Automatic Inactivity Turn-off - The radio automatically
shuts itself off if four hours go by without the micro-
controller detecting input from the volume, PTT or
channel controls.
Battery Saver - Enabling this option allows the radio
to go into battery saver mode when the radio remains
idle. The power saver begins after eight seconds of
inactivity.
Battery Saver Off Time - This is the cycle time that
the radio is off in battery saver mode before it checks
for a received signal. A long Battery Saver Off Time
may cause the user to miss the beginning of the first
message when in battery saver mode.
Beep Volume Level - The radio can be programmed
for a fixed beep volume or for a beep volume that is
adjusted with the Volume controls. If fixed beep
volume is selected, the fixed level can be set between
0 – 100%.
Busy Channel Transmit Inhibit - This keeps the radio
from broadcasting if the channel is busy, and is often
used in conjunction with Disable Monitor. If you press
the PTT when the channel is busy with a signal not
intended for your radio (not carrying your tone code),
this feature sounds a "busy" tone in the speaker and
keeps the transmitter turned off.
Channel Beep - This will cause the radio to emit a
short Channel beep whenever the channel is
changed. If not set the radio only emits the Channel
beep when Channel 1 is selected.
Channel Display Power Saver - The display will turn
off during power saver “sleep” time. If power saver is
not enabled or this option is not set, the Channel
Display will be lit as long as the radio is on. The
Channel Display will always be lit on a Scan Channel,
regardless of this setting.
Digital Quiet Call RX Invert - The programmed code
is inverted for receive mode only.
Digital Quiet Call TX Invert - The code is inverted for
transmit mode.
Disable Monitor - This function may be programmed
to keep the radio user from listening to other
licensees on a shared channel. QC or DQC must be
used for this option to have any affect, and the
Encode Only feature disabled.
Maximum Number of Channels - The number of
channels available on the radio can be set from 1 to
10.
Narrow Band Channel - Any channel can be set to
operate in narrow band mode, reducing the transmit
deviation to 2.5 KHz.
Programming Password - An 8-character password
can be entered to restrict reading of the radio
information. Once a password is programmed into
the radio access to all programming information will
not be possible without first entering this password.

PROGRAMMING THE RADIO PBS-446D
15
PTT Programming Mode Enabled - This feature
allows channel programming from a table of pre-
determined frequencies using the radio PTT switch.
Quiet Call (CTCSS) - Programming a Quiet Call code
allows you to screen out transmissions that do not
carry your code. Your code is broadcast when you
press the PTT to make a call.
Quiet Call Encode Only - The Quiet Call code
programmed for the channel is transmitted with your
calls. However, no Quiet Call code is programmed
for receive mode, allowing all traffic on the channel to
be heard.
Receive Frequency - The radio frequency that
receives broadcasts from other units.
Receive Squelch Tone - The receiving radio beeps at
the end of each received transmission.
Scan Channel - The radio can be programmed for a
single scan channel. See Scan Channel Options for
details.
Squelch Tightener - This feature reduces distant "co-
channel" or other interference for channels that are
not programmed with Quiet Call. Carrier squelch is
set for maximum sensitivity at the factory, but may be
adjusted to mute weak signals
Transmit Frequency - The radio frequency that
broadcasts to other units.
Transmit Time Out Timer - This feature automatically
shuts off the transmitter (ending your call) if you hold
down the PTT button continuously for 60 seconds.
The radio sounds a tone when the transmitter shuts
off.
Turn On To Medium Volume Level - The volume level
is at mid-range when the radio is first turned on.
Normally, the volume level is low when the radio is
turned on.
2-Tone Paging Decode – Any channel can be set for
2-Tone paging decode. See 2-Tone Paging Options
for the details of 2-Tone programming.
2-Tone Paging Options
The following programmable options are available on
any channel programmed for 2-Tone paging decode:
1st Tone – Set the frequency and duration of the 1st
paging decode tone.
2nd Tone – Set the frequency and duration of the 2nd
paging decode tone.
All Call – Enable, and set the frequency and duration
of an All Call paging decode tone.
2-Tone Transpond - The radio can transmit a
transpond tone after a 2-tone page has been
successfully decoded to let the paging dispatcher
know that the page has been received.
2-Tone Squelch When Selected - The radio can be
automatically set for 2-tone paging decode whenever
the channel is selected.
2-Tone Group Call - Enable Group Call tone
decoding. Group Call tone decoding is when the 1st
tone is received continuously for over 5 seconds.
2-Tone Auto Reset - The radio can automatically
reset the 2-tone paging decoder 16 seconds after a
page has been received if that page is not answered.
2-Tone Monitor Trip - The radio can automatically go
into carrier squelch mode any time a 2-tone page is
received, and will remain in there until the paging
decoder has been reset.
Scan Channel Options
The following programmable options are available to
the Scan Channel:
Scan Resume Delay Time - Sets the time that the
radio will wait before it resumes scanning after having
received a signal on one of the scanned conventional
channels. If the Disable Scan Resume Delay option
is checked on the Conventional Channel screen for
any of the channels, the Scan Resume Delay Time is
ignored on that channel.
Scan Resume Delay Time after TX - Sets the time
that the radio will wait before it resumes scanning
after transmitting on one of the scanned channels.
Channel Lockout - Allows the user to temporarily
remove a channel from the Scan list while operating
the radio.
Last Active Channel Beep - After receiving a signal
on the Scan Channel, the user can step through the
channels by pressing the Channel Selector button
until a beep is heard, identifying the last channel that
was received on the Scan Channel.
Priority Scan Enabled - Sets the first channel in the
Scan list as a priority channel. While scanning, the
radio will look at the priority channel at a programmed
interval.
Priority Scan Look Time - Sets how often the radio
will look for the priority channel when priority scan is
enabled.
Priority Beeps - The radio can beep if it receives a
signal on the priority channel while in Scan mode.
Jump to Priority on PTT - The radio can transmit on
the Priority channel when the PTT is pressed while in
Scan mode, otherwise it will transmit on the channel
that last received a signal.
Scan List - Up to nine channels may be added to the
Scan List. If priority scan is enabled, the first channel
in the scan list is the priority channel.

THEORY OF OPERATION PBS-446D
16
INTRODUCTION
The PBS-446D is a ten-channel base station
transceiver built on a single multi-layer printed circuit
board. Both sides of the main printed circuit board
are populated with components, with the top side
containing only surface mounted components.
The PBS-446D is frequency synthesized, with all
functions of the radio controlled by microcontroller.
POWER SUPPLY AND VOLTAGE DISTRIBUTION
Power is supplied to the PBS-446D base station radio
from a Ritron 1A wall-mounted power supply RPS-1A
through J1, a 5.5mm coaxial connector located on the
top end of the case. J1 is connected to the PCB
through P3.
An AC line filter consisting of L1, L2, L3, L4, L5, L6,
and associated components strip 60 Hz hum off the
supply line. F301 is a 3A fuse in series with the
supply line for short circuit protection. Darlington
transistor Q 3, C 47 and zener diode provide
additional AC filtering, regulate supply voltage at 12
VDC, and prevents a high voltage from being applied
to the radio circuitry.
SW301 ON/VOL UP switch is pressed to turn on the
PBS-446D, turning on voltage pass transistor Q304
via R302 and CR303. Q304 supplies power to U309,
a +5 VDC regulator used to power microcontroller U1.
Pin 5 of U1 turns on Q303, which keeps Q304 turned
on after SW301 has been released. Power is
removed from the PBS-446D by pressing the VOL
DN/OFF switch SW303 until a beep is heard from the
speaker, at which time Q304 is turned off.
+5 VDC regulator U309 supplies power directly to
microcontroller U1, audio gates U304, reference
oscillator Y302, synthesizer U401, 7-segment LED
display U5, and PTT detect transistor Q302.
The T/R output at Pin 16 of U1 lets Q101 switch the
regulated +5 VDC to the receiver. Voltage from
digital pot U306B will turn on Q202, which turns on
voltage pass transistor Q201. With Q201 emitter
connected to the +VBATT battery supply, the
collector output is connected to the emitter of Q202
through voltage divider R202/R203, allowing the
voltage at the base of Q202 to adjust the TX+V
voltage from +6 to +8 VDC for TX power control.
Power Strobe
The PBS-446D base station includes a power strobe
feature for battery powered installations. Power
strobe reduces battery current drain by periodically
removing voltage from part of the radio. The strobe
off cycle time is programmable using the PC
Programming Kit. The +5V SW power strobe output
at Pin 24 of U1 controls Q5, which switches the
regulated +5 VDC to the audio processing circuitry
and the synthesizer circuitry. This includes:
•U303A 2.5 VDC voltage reference (Vag) for bias on
audio processing circuitry
•U303C audio high pass filter
•U308 and U305A audio low pass filter for sub-
audible frequencies
•U303B audio limiting amplifier
•U306 digital potentiometers,
•U305B audio summing node amplifier
•U303D audio low pass filter
•U303D amplifier for 2-tone decoding
•U305C AGC microphone amplifier
Low Voltage Detection
Supply voltage is measured at A/D input Pin 17 of U1
through voltage divider R303/R305. The radio will
emit a periodic beep if low supply voltage is detected,
and will turn the radio off if the voltage drops below
+5.2 VDC. This is to protect the microcontroller and
its EE memory from corruption due to low supply
voltage.
REFERENCE OSCILLATOR
Reference oscillator Y302 is a 1.5 ppm temperature
controlled, voltage controlled oscillator (TCVCXO)
operating at 14.4 MHz. The Pin 4 output of the
TCVCXO provides a reference for the frequency
synthesizer U401 at Pin 8, and is amplified by Q6 to
provide a clock signal at microcontroller U1 pin 32.
The Y302 pin 4 output is also multiplied up to 43.2
MHz by Q105 and its associated circuitry to provide a
receiver 2nd local oscillator signal.
SYNTHESIZER
The PBS-446D radio is built around a common
phase-locked loop (PLL) that consists of a voltage-
controlled oscillator (VCO) and a frequency
synthesizer. The PLL generates both the receiver 1st
local oscillator and transmitter carrier signals. Control
signals from microcontroller U1 and Reference
oscillator Y302 are routed to frequency synthesizer
U401 per the following chart:
Pin Numbers
U1 Y302 U401
Clock 8 - 11
Data 7 - 12
Latch 25 - 13
LD 8 - 14
T/R SW 16 - -
REF IN 32 4 8
+5 SW 24 - 10
+5V 10, 20, 28 2 7, 15, 16
Q404, CR401, C414 and associated components
provide a filtered supply for the VCO oscillator and
buffer amplifiers.

THEORY OF OPERATION PBS-446D
17
Prescaler Divider / Synthesizer Controller
U401 contains both a prescaler and synthesizer
controller. The prescaler squares and divides the
VCO output present at pin 6 by either 8 or 9,
determined by a synthesizer controller logic signal.
The exact number of times the prescaler is instructed
to change divisors is determined by the channel
frequency.
U401 contains a digital phase detector that works as
follows: when an operating channel is changed or the
receive/transmit mode switched, a new synthesizer
operating frequency is selected. Microcontroller U1
clocks new data into U401 internal buffer in
synchronization with clock pulses. The channel
information is stored in EE memory of U2 and is
loaded into RAM when the channel is selected.
Once new data is loaded into the buffer, a single
pulse from U1 appears at U401 to instruct the
synthesizer controller to latch and execute the new
data. U401 utilizes internal circuitry to determine
whether the present VCO output frequency is correct
by comparing the phase and frequency of the VCO
signal at Pin 6 to the 14.4 MHz reference oscillator at
Pin 8. U401 produces an output signal at Pin 2, a
single-ended phase/frequency detector output,
proportional to the phase difference between the two
input signals.
The loop filter C429, C427, R419, R420, R418, and
C426 transform the Pin 2 output signal to a DC
voltage for application to the VCO tuning varactor
CR402. The synthesizer system is “locked” when the
phase and frequency of both the reference and the
divided VCO signal are the same.
VCO / Buffer Amplifiers
Q403, L401, CR402 and associated components
form the VCO (Voltage Controlled Oscillator), a
resonant circuit that oscillates at frequencies from
416 MHz in receive (receive frequency - 43.65 MHz)
to 470 MHz in transmit. Varying the voltage at CR402
changes the varactor capacitance, which in turn
alters the VCO output frequency.
When in transmit mode a +5 VDC T/RSW signal is
applied to Q406, which turns on Q405 to draw current
through pin diode CR404 and L403. With CR404
biased on, L402 is effectively shorted to ground,
shifting the VCO frequency up 43.65 MHz.
Q401 and Q402 are buffer amplifiers, with Q402
feeding in the input of the synthesizer at Pin 6 and
Q401 feeding the receiver 1st local oscillator and the
transmitter pre-amplifier.
Oscillator Modulation
When the PBS-446D is in transmit, modulation
balance control U306E passes TX audio through to
the VCO modulation input at R416. TX audio is
applied to varactor CR403 to modulate the VCO. TX
audio is also routed to the Pin 1 input of TCVCXO
reference oscillator Y302. Low frequency tones
modulate the reference oscillator because the
synthesizer is not able to track them.
DIGITAL POTENTIOMETERS
U306 contains 6 digital potentiometers programmed
by U1, sharing the same clock and data outputs used
by the synthesizer and a separate Digital Pot Latch
signal from Pin 3. The digital potentiometers are
used in conjunction with U305B, a summing node
amplifier used for modulating the VCO and reference
oscillator. U306A, B, D, E, and F can only be
changed through serial programming, and can only
be performed by an authorized licensed RF
technician.
U306A is connected through R352 to the Pin 6 input
of U305B. U306A adjusts the DC output of U305B to
tune the reference oscillator frequency.
U306B is connected to the base of Q202 for transmit
power control. Q202, Q201, R202, and R203 adjust
the supply voltage to the transmitter.
Volume control U306C applies the processed voice
band signals at U303D to audio amplifier U307 when
in receive mode. Depressing the ON/VOL UP switch
SW301 increases the setting of U306C while VOL
DN/OFF switch SW303 decreases it.
Transmitter tone deviation control U306D applies the
output of the selective signaling low-pass filter U308
to the Pin 6 input of U305B through R350. U306D is
completely closed in receive mode.
Transmitter modulation balance control U306E is
used to apply the Pin 7 output of U305B to the VCO
modulation input. This will set the ratio of the
modulating signal applied to the VCO and the
reference oscillator. U306E is completely closed in
receive mode.
Transmitter voice deviation control U306F applies the
processed voice band signals at U303D to the Pin 6
input of U305B through R349. U306F is completely
closed in receive mode.
RECEIVER
As mentioned before, Q101 switches the regulated
+5 VDC to the receiver. The +VRX receiver voltage
is switched at the strobe duty cycle if programmed for
power strobe.
RF Amplifier
A received signal from the antenna passes through a
low-pass filter (C218, C217, L211, C101, and C202)
to the receiver headend. L101 and the associated
capacitors form a bandpass filter ahead of low-noise
RF amplifier Q102. L101 and C103 provide a notch
at the image frequency, 87.3 MHz below the receive
frequency. The amplified RF signal is applied to a 2-
pole bandpass filter consisting of L103, L104, and
associated capacitors. This circuit is tuned for 450 to
470 MHz.
1st Mixer
The amplified received input signal is applied to the
gate of FET mixer Q103. The 1st local oscillator
signal from the synthesizer module is applied to the
source of Q103. L106, C117 and C118 tune the drain