Pyramid SVR-200 LA User manual

LALA
VHF: 29 - 50 MHz

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SVR-200 Service Manual
SVR-200
Vehicular Repeater
Thismanualisintended forusebyqualifiedtechniciansandincludesallnecessaryinformationpertainingtothe
SVR-200 operation, circuit design and maintenance. Changes that occur after date of printing will be
incorporatedinsupplementalservicepublications.

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SVR-200 Service Manual
Foreword
Scope of this manual
This manual contains the specifications, functional description, operating instructions, schematic, parts locator
and parts list for the SVR-200 synthesized vehicular repeater.
This manual is intended for use by qualified service technicians to aid them with installation, interfacing,
alignment and trouble shooting of the SVR-200 when used with other land mobile radios.
Service manual revisions
Component changes, additions and deletions may occur in the circuit design to improve operation and will be
reflected in future releases of this service manual. Specifications and circuit changes are subject to change without
prior notice or obligation by Pyramid Communications.
Safety Information
The SVR-200 is designed to operate within all applicable Federal regulations at the time of manufacture. Proper
operation and service procedures will assure continued compliance with these regulations:
• Do not operate the SVR-200 without an antenna or appropriate RF load connected to the antenna connector.
• Do not operate the SVR-200 in the presence of unshielded electrical blasting caps or explosive environmental
conditions.
• Do not operate the SVR-200 while refueling the vehicle or in the presence of explosive fumes.
• Do not operate the SVR-200 with persons standing closer than 2 feet from the mobile or repeater antenna.
FCC information
The SVR-200 complies with the FCC rules parts 90 and 22 for radio frequency transmitters. The user must apply
for a license to operate the SVR-200 transmitter pursuant to parts 90.243 and 90.247. Other FCC rules may apply
depending on the class of service the user qualifies for. A complete listing of FCC rules and regulations may be
ordered from:
Superintendent of Documents
Government printing office
Washington DC 20402
The following information pertaining to the SVR-200 should be included in the FCC license application:
Type Acceptance: LRUSVR-200LA
Output Power: 0.25-2.0W
Emission designator: 20K0F3E
Frequency band: 29-50 MHz
Number of Channels: 1/14

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SVR-200 Service Manual
Specifications
Transmitter:VHF
Frequency Range: 29-50MHz(29-44MHzand 36-50 MHz)
Rf power out: 250mW - 2W
Spurious emissions: -50dBc
Freqstability -30°~+60°C: 15 PPM
Modulation: 20K0F3E
Hum and Noise: -40
Audio response (300-3kHz): Flat or +6dB/octave
Audio distortion: <3% @ 60% deviation
Local mic sensitivity: 300mV-5VPP
FCC Type Acceptance: LRUSVR-200LA
Industry Canada Approval: 2390XXXXXX
Receiver:
Frequency Range: 29-50MHz
RF sensitivity: .35µV
Squelch sensitivity: .2µV to 2µV adjustable
Modulation acceptance: ±7.5
Selectivity: 60dB
Spurious/image rejection: 60dB
IMD response: 60dB
Frequency stability: 1.5PPM
Audio response (300-3kHz): Flat or -6db/octave
Audio output: 0-5VPP AC coupled
Local Rx Audio: 400 mW 8 Ohms
PowerRequirements:
DC Supply 13.6VDC
Standby 170mA
Receive 250mA
Transmit 1 A @ 2W
Physical:
Dimensions: 5.275"Wx 6"L x1.12"H
Weight: 18oz.
Case: One piece extruded aluminium

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SVR-200 Service Manual
Functional Description
Generally, vehicular repeaters are used as mobile extenders in cross-band operation: the link is VHF Low Band
simplex and the mobile is Lo-band, VHF, UHF or trunking. In-band operation is possible, but care must be taken
to prevent interference between the mobile's higher power transmitter and the repeater receiver. Proper frequency
selection and antenna placement are important even in cross-band operation, but especially for inband use. The
use of low power pre-selector cavities may be placed in line with the repeater antenna cable since it is simplex and
low power.
Important Note
The SVR-200 operates on simplex frequencies; part of the multi-vehicle format dictates that all of the
SVR-200s must be able to monitor all link traffic on site and be able to determine if a handheld is transmitting, or
if other repeaters are transmitting. The handhelds must transmit CTCSS, but should be carrier squelch receive.
The handhelds should not use CTCSS decode if the repeater is utilizing the multi-vehicle format, as this will
interfere with the priority sampling which is essential for multi-vehicle operation. Also, the handhelds would have
to have different encode and decode tones in order for the repeater to be able to tell the difference between
handhelds and other repeaters, so the handhelds would not be able to hear each other. The repeaters should not
transmit CTCSS unless used only in a single vehicle environment.
When the user leaves the vehicle, they activate the SVR-200 via their mobile radio front panel or a separate
switch. When the mobile radio is receiving carrier and proper tone, the SVR-200 will begin transmitting on the
handheld’s receive frequency. The user is able to hear and respond to all radio traffic, including other handhelds
at the site. The SVR-200 can be programmed to give the handhelds priority in a conversation by periodically
sampling for handheld activity (carrier and proper tone) during base-to-portable transmissions. During sampling,
if the SVR-200 detects a handheld transmission, it will cease transmissions, key the mobile radio and repeat
portable-to-base. This allows the handheld to respond during repeater hang time or during full duplex interconnect
calls. Priority sampling can be enabled/disabled through PC programming and the interval can be programmed
between .25 seconds and 2.5 seconds in .25 second increments.
The SVR-200 has a fixed 3 minute time out timer for base-to-portable transmissions. If the mobile COR is
active for more than 3 minutes (and the SVR-200 is the priority unit) it will send a double blip and cease transmission
until the mobile COR is inactive. The 3 minute time-out is in affect regardless of whether the SVR-200 is
programmed for priority sampling or not.
Multi-vehicle operation
When the SVR-200 is first activated, it will transmit a short “lock tone” that alerts the user that the system is
functioning. It will then assume the priority status and be ready to repeat any base-to-portable or portable-to-base
transmissions. If another unit arrives on scene and is activated, it too will transmit the “lock tone”; when the first
SVR-200 detects the lock tone from the second unit, it will increment a “priority counter” and will no longer repeat
any transmissions. The recently arrived unit will be the priority repeater, and the first unit will be 1 count away from
priority. This process will continue for each unit that arrives at the site, creating a priority hierarchy for up to 256
vehicles, each with a unique count and only one unit at priority status. The SVR-200 will not transmit it’s lock tone
if the radio channel is busy when first enabled. It will wait in non-priority status until all transmissions cease, then
send its lock tone and become the priority unit.
Even though the other SVR-200s are not at priority status, they will continue to monitor the channel for activity.
If the priority unit were to leave the scene or become disabled, the other units will detect the condition to repeat
and determine that there is no priority unit repeating the transmission. They will then begin to decrement their
priority counters until one of them reaches the priority status and begins repeating the transmission. Since the
SVR-200s are all at different counts, only one will reach priority status and begin transmitting. The other units will
sense the new priority repeater and cease counting down, preserving the priority hierarchy.

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SVR-200 Service Manual
If another unit were to arrive from a different scene and it is still the active priority, there will be two active
repeaters on the air when a condition to repeat exists. When one of the SVR-200s unkeys to check for handheld
activity, it will detect the presence of the other active SVR-200 and increment it’s priority counter and cease
transmission. This is the self clearing mode to prevent radio collisions.
If the handheld operator is out of the vehicle and their partner still in the vehicle were to key the mobile radio
using the local mic, the SVR-200 will detect the local PTT and repeat the transmission to the other handhelds so
that both sides of the conversation will be heard by everyone on the link. The local mic repeat function can be
enabled/disabled via the PC software.
The SVR-200 also has a local receive audio speaker jack that enables the person in the vehicle to monitor
portable-to-base transmissions that are being repeated through the mobile.
If the users wish to communicate portable-to-portable without accessing the mobile repeater, they may transmit
on the same frequency without CTCSS (or a different CTCSS); the SVR-200 only responds to carrier and proper
tone from the handhelds.
Trunking operation
When the SVR-200 is connected to a trunking mobile and the handheld operator wishes to access the system,
they key their handheld briefly then release. The SVR-200 will attempt to acquire a voice channel on the trunking
system by keying the mobile for 200mS and monitoring the on-air detect line from the mobile. If it does not see
the radio transmit at all (system is busy), it will send a low tone to the hand held operator to alert them that the system
is busy. The SVR-200 will automatically retry every 5 seconds and send busy tone to the handheld with each
unsuccessful attempt to indicate progress of the call attempt. If unsuccessful after 30 seconds, the SVR-200 will
transmit intercept tone to alert the handheld operator that the call attempt failed.
When the SVR-200 detects that the mobile is transmitting, it will continue to monitor the on-air line until the
transmitter remains keyed for at least 250mS to ensure that the radio is merely handshaking or retrying. After
successful acquisition of a voice channel, it will continue to hold the mobile PTT active for 2 seconds and transmit
a go-ahead blip to the handheld operator. The user then keys their handheld to speak on the voice channel. If the
user does not key up within the 2 second period, the SVR-200 will unkey the mobile and send intercept tone as
before.
If the user keys their handheld only once, or they key the first time for more than 1 second, the SVR-200 will
cancel the call attempt and send intercept tone to the handheld operator. All of the queuing and error tones will only
be sent if the handheld is not transmitting to ensure that the user hears the proper tones.
LEDs
CPU: Flashes at a 1 Hz rate to indicate proper operation of the microprocessor.
PRI: When on, indicates that the unit is at priority count zero and will repeat all transmissions.
RCOR: Repeater Carrier detect.
RTONE: Repeater sub-audible decode; when on, indicates a condition to repeat portable-to-base.
RTX: Repeater transmit indicator.
MCOR: Mobile unmute detector indicating a condition to repeat base-to-portable.
MTX: Mobile transmit indicator.
OPT: Should be on steady during programming operations only. If OPT LED flashes at 10Hz rate, it is an
indication that the PLL did not lock within the allotted 50mS and the unit should be serviced.

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SVR-200 Service Manual
Installation
Before installing the SVR-200, ensure that the RF and repeater sections are properly aligned per the tuning
instructions on pages 8-14 of this manual. Additionally, ensure that the SVR-200 jumpers are properly configured
for use with the particular mobile radio that it will be connected to:
J1 Controls the maximum drive level of the transmit audio output to the mobile radio. If J1 is installed, output amp
U1B will have an adjustment range of 0-100 mVPP. If J1 is removed, U1B can be adjusted between 0-5VPP.
J2 Controls the output impedance of the transmit audio line to the mobile radio. If connected to a low impedance
point in the mobile, installing JP2 sets the output impedance to 600 ohms. If JP2 is open, the output impedance
is 2.2Kohms. Install the jumper for radios that require a lot of modulation drive or that have low impedance
microphone circuits. Remove the jumper if the SVR-200 installation decreases local microphone audio at the
mobile.
J3 Used for testing the SVR-200 receiver and setting the lock tone deviation transmit level. If JP3 is shorted at
power up, the SVR-200 receiver will be active all of the time and receiver audio will be heard at the speaker
regardless of the repeater squelch setting or CTCSS tone decoded. Remove the jumper and turn the SVR-200
off to return to normal operation. If JP3 is shorted while power is applied, the SVR-200 will go into transmit
mode and send lock tone for as long as the jumper is shorted. Remove the jumper to return to normal operation.
J4 Used to internally tie the local mic input of the SVR-200 to the transmit audio output line which is usually
connected to the mic hi line in the mobile.
J5 Used to internally tie the on-air detect input of the SVR-200 to the PTT output. Do so only on conventional
radios; trunking radios must have the on-air detect line connected to a line indicating that the radio is
transmitting.
J6 Changes the maximum gain of the local mic input amp from unity (Out) to 10x (In).
J7 Changes the maximum gain of the receive audio line input from unity (Out) to 7x (In).
J8 Adds a pull up (+ position) or pull down (- position) resistor to the remote enable line (blue).
J9 Adds a pull up resistor (10K to 5VDC) to mobile COR line (violet)
Make the connections between the mobile radio and the SVR-200 cable as follows:
Pin 1: Ground. Connect to the radio's chassis or ground plane.
Pin 2: Mobile transmit audio. Connect to the mobile transmit audio path or tone input. If connected before
pre-emphasis, ensure that the SVR-200 is programmed for de-emphasis (common data). If connected
after pre-emphasis, ensure that the SVR-200 transmit audio path is programmed as flat. Pin 2 is AC
coupled and has an output impedance of 600 or 2.2Kohms (determined by J2). RV3 sets the transmit
audio output level and J1 sets the adjustment range between 0-5VPP (J1 open) or 0-100mVPP (J1
shorted).
Black/Shield
White

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SVR-200 Service Manual
Pin 3: Remote enable/disable. Connect to the radio's auxiliary output or a separate switch to remotely enable
or disable the repeater. If this line goes high to activate the repeater, ensure that JP1 is set to the “+”
position. If this line goes to ground, set JP1 to the “-” position. J8 has two positions to add a pull up
(+) or pull down (-) resistor to this line if used with an open collector or dry contact output.
Pin 4: Mobile PTT output. Connect to mic PTT on the mobile radio, or a line that goes active low to transmit.
Pin 4 is an open collector output rated at 100mA at 50VDC.
Pin 5: 12 VDC input. Connect to the radios 12V switched supply or a point capable of supplying at least 1.5A
of current.
Pin 6: Mobile receive audio. Connect this line to the mobile receive audio path before the volume control.
If pin 6 is connected before de-emphasis, ensure that the SVR-200 receive path is programmed as flat
(common data). If connected after de-emphasis, program the receive path for pre-emphasis. Pin 6
is AC coupled and high impedance (>15K ohm). RV5 sets the receive audio level sensitivity; this input
should be between 30mVPP and 5VPP. J7 sets the gain of the receive input amp. If open, the input
has a maximum gain of one; if installed, the input has a maximum gain of 7.
Pin 7: Mobile COR detect. This line is used to indicate when the SVR-200 should repeat the transmission
to the handheld. Connect to a logic point in the radio that indicates proper tone and carrier have been
detected or the audio unmute line. If this line goes more positive during an unmute condition, program
the mobile COR line as active high (common data). If the line goes more negative during an unmute
condition, program the mobile COR line as active low. The input from pin 7 is high impedance and does
not have to go rail to rail. The SVR-200 uses a voltage comparator as a COR threshold detector. RV1
sets the mobile COR threshold level and should be set for half way between the mute and unmute levels
at pin 7. Example: If Pin 7 is connected to a point that goes from 0VDC (mute) to 5VDC (unmute),
set RV1 for 2.5VDC and program the mobile COR line as active high. If Pin 7 goes between 7.2VDC
(mute) and 5.8VDC (unmute), set RV1 for 6.5VDC and program the mobile COR line as active low.
Pin 8: Local mic audio. If programmed for local mic repeat, the SVR-200 will go into transmit mode and
repeat the audio from this line whenever the mobile radio is keyed by the local mic. Connect this line
to the mobile transmitter audio path before limiting or filtering. This input is AC coupled and high
impedance (>5.6Kohms). The input level at this pin should be 300mV to 5VPP. RV2 sets the local
mic sensitivity. If the mic high line has sufficient drive for this input, install J4 and leave pin 8
unconnected. J6 sets the gain of the local mic input amp. If open, the maximum gain is one; if installed,
the maximum gain is 10.
Pin 9: On-Air detect.
Trunking:Connect to a point in the radio that indicates the mobile transmitter is actually on the air.
This is not the same as mic PTT. If pin 9 goes positive during transmit, program the on-air detect line
for active high (common data). If pin 9 goes to ground during transmit, program the on air detect line
for active low.
Conventional: Used for local mic repeat indication from the mobile. Connect pin 9 to pin 4 of the
SVR-200 and program the on-air detect line for active low. Solder jumper J5 will connect pin 9 to pin
4 (PTT output) and can be used on conventional systems only. Do not install J5 for trunking
operation.
Install the SVR-200 in the vehicle using the supplied mounting bracket and hardware. Install the unit where
it will be easily visible by the driver and will not interfere with the drivers vision or constitute a hazard during a vehicle
collision. The SVR-200 mounts in the bracket using the four 8-32 x ¼" machine screws. Do not use longer screws
to mount the SVR-200 to the bracket or circuit damage may result.
Blue
Green
Red
Yellow
Violet
Brown
Gray

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SVR-200 Service Manual
Alignment
Before aligning the SVR-200, ensure that the mobile radio is aligned per the manufacturer’s service procedure;
Ensure that the SVR-200 is properly programmed and the jumpers are set per the previous section.
In order to properly align the SVR-200, you will need two service monitors and the mobile radio that the repeater
will be installed with. Refer to figure 1 for alignment points.
Dis-assemble the repeater by removing the two cap screws on the rear panel and the phillips screw on the
bottom. Slide the main circuit board out of the housing with the rear panel attached. Connect one service monitor
to the SVR-200 TNC jack and the other to the mobile antenna jack. Connect the cable from the mobile radio to
the SVR-200 (See figure 4 on page 14). Turn on the mobile and activate the SVR-200.
Adjust the repeater squelch control (RV9) so that the repeater COR led is off. Adjust the mobile so that the audio
is squelched.
SVR-200 Transmitter
1. Transmitter Output: Short J3 and adjust RV10 for maximum. Confirm the SVR-200 RF Power out is at least
2W. Adjust RV10 for 250 mW. The SVR-200 case is integral to the voltage regulator heat sink and the unit
should not transmit at full power when removed from the case for extended periods.
2. Transmitter frequency: Adjust the TCXO on the RF board for the transmit frequency.
3. Maximum deviation/lock tone deviation: Adjust RV7 (lock tone deviation) for maximum. If the SVR-200
is programmed for sub-audible encode, adjust RV6 (CTCSS) for minimum. Adjust RV8 (repeater deviation)
for 95% deviation. Adjust RV7 for 60% deviation. Remove J3.
4. Mobile COR: Measure the voltage at TP2 on the SVR-200 main PCB and record. Set the mobile service
monitor for the mobile receive frequency, 1mV RF output and CTCSS modulation of 15% deviation. Measure
the voltage again at TP2 and record. Turn the mobile service monitor off and adjust RV1 on the SVR-200 main
board for the halfway point between the two voltage readings as read at pin 3 of U1.
5. RX audio sensitivity/CTCSS deviation: Set the service monitor connected to the mobile for the mobile receive
frequency and 1mV RF output. Modulate the signal generator with a 1kHz tone at 60% deviation and CTCSS
tone at 15% deviation. Ensure that the SVR-200 mobile COR and repeater PTT LED’s are on. Adjust RV5
on the SVR-200 main board for 60% deviation as read on the service monitor connected to the SVR-200. If
programmed for sub-audible encode, remove the 1kHz tone deviation from the mobile service monitor and
adjust RV6 on the SVR-200 main board for 15% deviation. Turn the RF output from the mobile service monitor
off and ensure that the SVR-200 mobile COR and repeater PTT LEDs are off.
6. Local mic repeat: If the SVR-200 is programmed for local mic repeat, key the mobile local mic and inject an
audio signal into the local mic to produce 60% deviation on the service monitor connected to the mobile.
Confirm that the SVR-200 repeater PTT LED is on; adjust RV2 for 60% deviation as read on the service
monitor connected to the SVR-200. Unkey the mobile radio.
7. RF power out: Short J3 and adjust RV10 for the operating power output. Open J3.

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SVR-200 Service Manual
Figure 1
Receiver
1. Receiver IF: Connect a DC voltmeter to TP1 on the SVR-200 main board. Set the service monitor connected
to the SVR-200 to the generate mode, receive frequency with a 1kHz tone and 60% deviation. Adjust the RF
output of the monitor for a 1VDC reading at TP1. Adjust T1 and T2 on the RF board for a maximum reading
at TP1.
2. Repeater squelch: Adjust the service monitor RF output for .5µV. Adjust RV9 on the SVR-200 main board
so the repeater COR LED is just on. Decrease the service monitor RF output to .3µV and ensure that the
repeater COR LED is off.
3. Transmit audio output: Adjust the service monitor RF output for 1mV. Turn the CTCSS modulation on and
set for 15% deviation. Confirm that the repeater COR, CTCSS and mobile PTT LED’s are on. Adjust RV3
on the SVR-200 main board for 60% deviation as read on the service monitor connected to the mobile radio.
4. Local Rx audio: Connect an 8 ohm speaker to P4 and set RV4 for the desired listening level. Turn off the
CTCSS modulation of the service monitor connected to the SVR-200. Confirm that the repeater CTCSS and
mobile PTT LED’s are off.
5. Lock Tone Decode: Change the 1kHz tone modulation to the lock tone frequency. Confirm that the PRI LED
goes off after approximately .5 seconds.
TP2

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SVR-200 Service Manual
Mobile Radio
Communications
Monitor A
Communications
Monitor B
SVR-200
Interface
Cable
Figure4

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SVR-200 Service Manual
Menu selections
File
Open: Allows you to load a previously saved file from disk. Enter the file name or select from the Windows Dialog
box. Only files with the .VR2 extension can be loaded.
Save: Allows you to save the current configuration to disk. Enter the file name to save as or select a previous file
from the Windows Dialog box to overwrite. The .VR2 extension is automatically added to the file name. The
program will prompt you before overwriting an existing file.
Print: Sends the current configuration to the selected printer. Make sure the printer is on line and paper is loaded
before executing this command.
Exit: You will be asked to confirm before exiting the program. The software will also prompt you if the
configuration has changed since program start up and data has not been saved to disk.
Data
Frequencies: Enter the transmit and receive frequencies and select the encode and decode sub-audio data. The
program will automatically round off the frequencies to the nearest channel step if incorrect data is entered. To
enter VHF offset frequencies (6.25kHz channel steps), go to common data and select the "VHF Offset" band.
To disable sub-audio encode operation, select "------"; sub-audio decode cannot be disabled.
Common data: Controls all of the options and input polarities of the SVR-200. Make sure all of the settings are
correct for the type of mobile radio the repeater is connected to or improper operation may result.
File name: This data is stored in the E²PROM of the SVR-200 during downloads.
Model: Select either SVR-200 (single frequency) or SVR-214 (14 channel).
Band: Select the proper frequency band to correspond with the model SVR-200 you are programming. This
selection is automatically set by reading the SVR-200. The IF frequency, injection side and channel step are
displayed next to the band selection. Select VHF Offset band for 6.25kHz channel steps.
Programming
Using the Software
The SVRCPS personalization software is used to program the SVR-200 for all of the operating parameters
and options. The software is compatible with Windows 2000 and later operating systems The software is menu
driven and on-line help is available at any time by clicking the left mouse button on the HELP icon on the right side
of the tool bar.
Important Note:
Before attempting to program the SVR-200 start the software and ensure the FY-1 programming cable is
plugged into the correct serial port. The com port may be selected under the “Transfer” menu. Plug the FY-1
programming cable into P3 on the front of the SVR-200; the OPT LED on the SVR-200 front panel should be on
continuously:

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SVR-200 Service Manual
Mobile COR polarity: Determines if the COR signal from the mobile is active high or active low.
Radio Type: Select either conventional or trunking. If a trunking mobile is selected, the SVR-200 will go through
the voice channel acquisition procedure during portable-to-base repeat mode.
On-air polarity: Select either active high or active low. This line is used to monitor the local mobile PTT for local
mic repeat on conventional radios. On trunking radios, it is also used to determine if the mobile is actually
transmitting.
TX Audio: If the mobile transmit audio output from the SVR-200 is connected after pre-emphasis in the mobile,
select Flat response. If connected before pre-emphasis or to the mic input, select De-Emp.
RX Audio: If the receive audio coming from the mobile is connected to the discriminator or before de-emphasis,
select Flat response. If connected after de-emphasis, select Pre-Emp.
Lock Tone: Select either 682.5, 832.5 or 847.5 Hz. All units in the system must have the same lock tone frequency.
Local mic repeat: Enables or disables the local mic repeat function; if enabled, ensure that the on-air polarity input
is correctly configured.
Courtesy Blip:(Firmware version 3.02 & above) Enables or disables the courtesy tone at the end of each
portable-to-base transmission. The tone verifies the handheld is within range of the repeater and transmission was
successful. It also serves to notify other handheld users that the channel is clear for use.
Pri-sampling: Enables or disables the pri-sampling feature of the SVR-200. If used in multi-vehicle
applications, this must be enabled for proper operation. During base-to-portable repeat mode, the SVR-200
transmitter will switch to receive mode to check for other repeaters or handheld activity. If another repeater is
detected (carrier without/wrong tone) the repeater will cease activity to prevent radio “collisions”. If handheld
activity is detected (carrier & correct tone) the SVR-200 will switch to portable-to-base repeat mode.
Sampling rate: If pri-sampling is enabled, this selects the sampling interval. The range is 0.25 seconds to 2.5
seconds in .25 second increments. The higher this setting, the longer the handheld operator must wait before
speaking after pressing PTT during base-to-portable repeat mode, since the repeater may still be in transmit mode
(there is no delay if the repeater is idle). If the interval is too short, some users may complain about the “chop”
that is heard in the handhelds.
Transfer
Send: Downloads the current configuration to the repeater. The program will prompt you to make the FY-1
connection before downloading. Download takes approximately 5 seconds.
Receive: Uploads the current data from the repeater. The program will prompt you to make the FY-1 connection
before uploading. Upload takes approximately 4 seconds.
Comm Port: Selects the serial port to use for uploading and downloading between the PC and the SVR-200. Comm
ports 1-4 are supported.
Help
Help is available at any time by clicking the left mouse button on the HELP icon on the right side of the tool
bar. The help is context sensitive and will depend upon where the cursor is located on particular menu displayed.

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SVR-200 Service Manual
Theory of Operation
Receiver:
The receiver is a double-conversion superheterodyne type, designed for narrow band FM reception. The first
local oscillator is derived from the frequency synthesizer. The second LO is crystal controlled.
RF Stage: The incoming RF signal from the antenna jack is directed to the first RF bandpass filter to improve
selectivity and then to the input of the RF amplifier. The output of the RF amplifier is then presented to a second
bandpass filter.
First LO/Mixer: The first LO signal is developed by the synthesizer and is mixed with the incoming signal to
produce the first IF frequency (70 MHz high side injection). The IF frequency is filtered by FL1A and FL1B and
amplified by the IF amplifier before being presented to the second LO/Mixer IC.
Second LO/Mixer: The first I.F. signal is presented to the second IF IC (MC3371) which performs the functions
of second LO, second I.F. amp and mixer, FM discriminator and squelch. The second LO crystal (69.545 MHz)
is mixed with the 70 MHz first I.F. signal to produce the second I.F. frequency of 455 kHz. A 6 pole ceramic filter
provides selectivity for the 455 kHz signal.
Detector/Squelch: The MC3371 demodulates the 455 kHz signal via quadrature coil to produce the audio and noise
components. The output of the MC3371 is the recovered audio and the RSSI voltage (receiver signal strength
indicator) which is compared by the controller board with a threshold voltage level for squelch setting.
Transmitter
The output of the VCO is buffered by U5 and amplified by U6. The output of U6 drives the RF driver Q6.
The collector of Q6 is fed by the transmit 9V line from Q5. The final amp Q7 is a class C power amplifier and
drives the output lowpass and harmonic filte. U8 is the antenna switch. RF output power is controlled by changing
the bias on the gate of Q7 via the TX 9V line (pin 3) from the controller PCB.
Control Board
Power Supply: DC power comes from the mobile radio via P1 pins 1 and 5. Fuse F1 and MOV VAR1 provide
over current and voltage spike protection. Q3 is the remote enable/disable pass switch, controlled by Q1 and Q2
via P1 pin 3. Q3 output is switched 12VDC and is presented to audio amp U6, and voltage regulators U7 and U8.
Bias voltage for the op-amp circuits is provided by voltage divider R68, R69 and buffer amp U2A.
Transmit audio path: Receiver audio from the mobile is input to the mic amp portion of U4; PC programming of
the SVR-200 provides flat response or +6db/octave pre-emphasis. The output of the mic amp is internally connected
to the limiter and lowpass filter. When a condition to repeat exists (base-to-portable) U4 audio is switched on and
audio is presented to amplifier/limiter and lowpass filter to remove audio components above 3kHz. U4 provides
-48db/octave of attenuation to out of band signals. Transmit audio is output on pin 22 of U4 and passes through
the final lowpass filter U2C to remove any clock noise generated by U4’s switched capacitive filters before being
presented to the RF module on P2 pin 6.

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Receive audio path: Receiver audio from the transceiver module is input on P2 pin 13 and presented to U5 pin
10 and pin 16. Pin 10 is the input of the receiver highpass filter to remove any sub-audible signals before being output
on pin 11 and sent to U4 for receiver audio processing. Pin 16 is the input to the sub-audible tone decoder section
of U5. Receive audio entering pin 7 of U4 is processed as flat, or -6db/octave depending upon PC programming.
The receive audio then passes through the internal lowpass filters to remove unwanted noise and output on pin 21,
where it is sent to the local receiver audio amp and mobile transmit audio output amp U1B. J1 selects either high
sensitivity (open) or low sensitivity (shorted) and J2 selects the output impedance (600/2.2K Ohms).
Sub-Audible tone signalling: U5 processes the sub-audible signal from the receiver by comparing the incoming
signal to previous samples in a noise correlator. If the signal is sufficiently coherent, the output of the comparator
is counted by the internal circuitry and an interrupt is generated to the main microprocessor. U12 reads the data
from U5 in 2 bytes: byte one contains the number of complete cycles detected within 122mS, and byte 2 contains
the number of internal clock cycles elapsed for the remainder. U12 performs a comparison of minimum and
maximum values allowed in a look up table and determines if the data is within the decode bandwidth for the
programmed tone.
In band tone signalling: Audio from the transceiver is also fed to U3B where it is amplified and limited for input
to the commutating switched capacitive filter made up by C23-C26 and P0.4-P0.7 of the microprocessor. The
microprocessor outputs four identical signals with 90° phase difference on the respective port pins. The resultant
wave form will be a function of the difference between the incoming signal frequency and the decode frequency
output by the microprocessor. The signal is buffered by U3C and amplified by U3A before being rectified and
filtered by D1 and C2. The resulting DC voltage is compared to the reference voltage by U3D. If the incoming
signal is within the decode bandwidth, the output of U3D will be a logic 1 and read by the microprocessor.
Logic and control: U12 is an Atmel 89C52 microprocessor with flash E²PROM memory. The microprocessor
provides all of the logic and control functions for the repeater including mobile/repeater PTT output, local mobile
PTT sense, mobile transmitter activity sense, audio switching, in-band & CTCSS detect, and repeater status
indications via DS4 and DS5 led arrays.
The 89C52 has four 8 bit ports that interface with the rest of the hardware on the controller board; a brief
description of each port follows:
P0.0-0.3 Channel Selector input; used only on SVR-214 version.
P0.4-0.7 These four lines make up the input to the switched capacitive filter network of C23-C26. During
receive mode, the lock tone frequency will be output on each of these lines with a 90° phase difference
between them at any given time. During transmit mode, these lines are in active and open collector.
P1.0-P1.2 LED data is output on P1.0 line every 10mSec. Data is loaded into shift register U9 8 bits at a time
and is clocked by P1.1. P1.2 latches the data into U9 for display.
P1.3 PLL latch enable output to the RF module. During transmit to receive and receive to transmit
transitions, this line is used to latch the serial data into the PLL shift registers. The serial data and clock
lines are shared with U10 (E²PROM) U4 (audio processor) and U5 (sub-audio processor).
P1.4 E²PROM chip enable, active high. Data is output to the E²PROM on P1.6 and clocked by P1.5. Data
is input from the E²PROM on P1.7. P1.4 will go active during read and write operations with U10.
U10 is written to every time the unit is programmed. U10 is read only at power up.

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SVR-200 Service Manual
P1.5 Serial clock line output. Serial data that is sent to the PLL, the E²PROM and the audio processor chips
are clocked by each low-high-low transition on this line.
P1.6 Serial data output. Data sent to U10, U4 and U5 are output on this line and clocked by P1.5.
P1.7 Data input to the microprocessor. Serial data is read from U10 (E²PROM) and U5 (sub-audio
processor) on this line.
P2.0 Lock tone output. Lock tone encode is generated by this pin at power up and during lock tone test mode.
All of the queuing tones are also generated by this pin for trunking operation.
P2.1 Lock tone decode input, active high. The output of lock tone decoder U3D is input on this line and
checked during receiver activity. If lock tone is detected, the microprocessor increments its priority
counter and ceases activity as priority unit.
P2.2 Repeater Tx enable. This line is used to turn on the TX 9V signal to the RF PCB. The output drives
buffers Q7 and Q6. The output of Q6 switches Q4 on during transmit for TX 9V. RV10 and APC
circuit U13 are used to set the TX 9V level for RF power control.
P2.3 Mobile PTT output, active low. This line is brought low to key the mobile radio during portable-to-base
repeat operations.
P2.4 Mobile COR input. U1A is a threshold detector for the mobile COR input on pin 7 of P1. The output
of U1A is read by the microprocessor on this port to determine if the SVR-200 should repeat base to
portable. Polarity of this input is determined by PC programming.
P2.5 Repeater COR input, active low. RSSI output from the RF module is sent to threshold detector U2D
for comparison with the squelch setting at RV9. R47 and R70 provide hysteresis to prevent chatter.
Repeater COR is used to enable the CTCSS decoder circuitry; the microprocessor will not decode
the signal from U5 unless repeater COR is also active.
P2.6 Chip select output for U4 (audio processor), active low. Serial data is sent to U4 on P1.6 and clocked
by P1.5. These lines are shared by U5, U10 and the PLL; data is ignored by U4 unless the chip select
line is asserted during data write operations.
P2.7 Chip select output for U5 (sub-audio processor), active low. Serial data is sent to U5 on P1.6 and
clocked by P1.5. These lines are shared by U4, U10 and the PLL; data is ignored by U5 unless the
chip select line is asserted during data read and write operations.
INT0 External interrupt #0. This line monitors the PLL lock detector output. The line is active high to indicate
the PLL is functioning on frequency during transmit-receive and receive to transmit changes. The
output will go briefly unlocked, then revert back to a locked condition. If the PLL does not achieve
lock within 50mS, the transmitter will be disabled and the OPT LED will flash rapidly to alert the user
that the unit should be brought in for service.
INT1 External interrupt #1 active low. This line is used by U5 to signal the microprocessor that it has
completed a decode cycle and data can be read. During receiver activity, this line will go active
approximately every 122 mS in the presence of sub-audio signalling. During transmit mode and
receiver activity without sub-audio signalling, this line will be inactive.

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SVR-200 Service Manual
T0 Test input, active low. Shorting J3 puts the microprocessor into test mode for alignment purposes. If
shorted at power up, the receiver will operate open squelch mode and audio will be heard at the local
speaker port regardless of carrier or tone input to the receiver. Although alignment is normally done
with the RSSI output at TP1, a Sinad reading can be obtained using this mode of the test input. All
other functions of the SVR-200 are disabled in this mode and power will have to be turned off then
on to reset the unit.
If J3 is shorted after power has been applied, the microprocessor will enter the lock tone test mode,
key the repeater and send the programmed lock tone for as long as J3 is shorted. Remove the short
from J3 to return to normal operation.
T1 On-air detect input. The on-air detect line (P1 pin 9) is used to detect local mic PTT from the mobile,
and in trunking mode, this line is used to detect that the mobile transmitter is actually on the air. The
input is buffered by Q10 and the polarity of the signal is determined by PC programming.
WR Turns the Rx 5V line on or off to the RF PCB.
RD Detects the version of RF PCB installed (UHF only).
TXD Transmit data output for programming. Data is sent to the PC on this line at 300 baud, 8 data bits, 1
stop bit and no parity. This line is active only during programming mode.
RXD Receive data input for programming. Data is received from the PC on this line at 300 baud, 8 data
bits, 1 stop bit and no parity. This line is also used to sense when the programming cable is inserted.
If RXD is grounded, the SVR-200 operates in the normal mode. If this line is high, programming mode
is entered and the OPT LED is on continuously.
Reset Active high input to reset the microprocessor. U11 provides a 350mSec delayed high signal to this pin
during power up or if the 5V line falls below 4.5VDC.
Xtal The microprocessor uses a 4.032MHz xtal for all of the timing and program execution clock cycles.
The output of the on board oscillator also drives the xtal input to U5. The output of U5 xtal oscillator
drives the input of U4.

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Notes
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SVR-200 Service Manual
Parts List
Reference Description Part #
C1,C5,C6,C9,C10,C12,C15,C18,C35,C37 ......................... .1µFd chip capacitor ............................ 1010-03-5104
C2 ..................................................................................... 22µFd 16V tantalum chip capacitor..... 1610-25-6226
C3,C27 .............................................................................. .047µFd chip capacitor ........................ 1010-03-5473
C7,C8,C13,C41 ................................................................. 220pFd chip capacitor ......................... 1010-03-5221
C11 .................................................................................... .0033µFd chip capacitor ...................... 1010-03-5332
C16 .................................................................................... 1000pFd chip capacitor ....................... 1010-03-5102
C17 .................................................................................... .0022µFd chip capacitor ...................... 1010-03-5222
C19,C20 ............................................................................ 22pFd chip capacitor ........................... 1010-03-5220
C40 .................................................................................... 0.5pFd chip capacitor .......................... 1010-03-5050
C21A,C21B ...................................................................... 6.8µFd tantalum chip capacitor ........... 1610-05-6685
C22,C32,C33,C34 ............................................................. 100µFd elctrolytic cap ......................... 1400-08-7107
C21,C23,C24,C25,C26 ...................................................... 0.47µFd tantalum chip capacitor ......... 1610-04-6474
C28,C29,C36 ..................................................................... 1.0µFd tantalum chip capacitor ........... 1610-04-6105
C14,C30,C38 ..................................................................... 2.2µFd tantalum chip capacitor ........... 1610-04-6225
D1,D2,D3,D6 .................................................................... BAV99 dual diode SOT23 .................. 3110-01-0099
D4,D5 ............................................................................... Schotkey diode SOT23 ........................ 3110-01-0301
DS4/DS5 ........................................................................... 8 position multi-color LED .................. 4003-08-0200
F1 ...................................................................................... 2A SMT Pica fuse .............................. 2610-04-0020
JP1 .................................................................................... 0.1" 3 position vertical header ............. 7300-53-0103
P1 ...................................................................................... DB-9 M right angle PCB .................... 7400-00-0011
P2 ...................................................................................... 0.1" 14 position vertical header ........... 7300-83-0114
P3 ...................................................................................... 2.5mm RA programming jack ............. 7401-02-0250
P4 ...................................................................................... 3.5mm RA speaker jack ..................... 7401-02-0051
Q1,Q2,Q6,Q7,Q9,Q10 ....................................................... 2N4401 NPN transistor SOT23 .......... 3010-01-4401
Q3 ..................................................................................... IRF-9540 P Ch MOSFET TO220 ....... 3300-08-9540
Q4 ..................................................................................... TIP 32 PNP transistor TO220 ............ 3000-08-0032
Q5 ..................................................................................... 2N4403 PNP transistor SOT23 ........... 3010-01-4403
Q8 ..................................................................................... NPN Darlington SOT23 ...................... 3010-01-0038
RV1,RV8,RV9,RV10 ....................................................... 10K 3mm SMT pot ............................. 2030-08-8103
RV2,RV3,RV5,RV7 ......................................................... 100K 3mm SMT pot ........................... 2030-08-8104
RV4 .................................................................................. 20K 3mm SMT pot ............................. 2030-08-8203
RV6 .................................................................................. 200K 3mm SMT pot ........................... 2030-08-8204
R82 .................................................................................... 10 Ohm chip resistor ........................... 2010-03-5100
R10,R23,R41,R52,R76 ...................................................... 10K chip resistor ................................. 2010-03-5103
R8,R11,R16,R21,R22,R24,R26,R30,R35,R44,
R47,R53,R66,R73 ............................................................. 100K chip resistor ............................... 2010-03-5104
R1,R2,R4,R6,R15,R17,R18,R31,R36,R74,R83 .................. 22K chip resistor ................................. 2010-03-5223
R3,R12,R13,R65,R72,R87 ................................................. 2.2K chip resistor ................................ 2010-03-5222
R5,R14,R86 ....................................................................... 820 Ohm chip resistor ......................... 2010-03-5821
R7,R48,R49,R63,R71 ........................................................ 5.6K chip resistor ................................ 2010-03-5562
R9,R81 .............................................................................. 56K chip resistor ................................. 2010-03-5563
R19,R20 ............................................................................ 470K chip resistor ............................... 2010-03-5474
R25,R29,R34,R51 ............................................................. 1.0M chip resistor ................................ 2010-03-5105
R27,R33,R37,R38,R45,R46,R85 ....................................... 33K chip resistor ................................. 2010-03-5333
R32,R70 ............................................................................ 27K chip resistor ................................. 2010-03-5273
R39,R40 ............................................................................ 150K chip resistor ............................... 2010-03-5154
R42 .................................................................................... 330K chip resistor ............................... 2010-03-5334

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SVR-200 Service Manual
R50,R77-R80 .................................................................... 15K chip resistor ................................. 2010-03-5153
R54-R62,R64 .................................................................... 330 Ohm chip resistor ......................... 2010-03-5331
R68,R69 ............................................................................ 4.7K chip resistor ................................ 2010-03-5472
R43.................................................................................... 68K chip resistor ................................. 2010-03-5683
R67.................................................................................... 8.2 Ohm 1W resistor ........................... 2000-10-5829
U1 ..................................................................................... TS922 dual op-amp ............................. 3410-01-0922
U2,U3 ............................................................................... MC3403 quad op-amp ......................... 3410-01-3403
U4 ..................................................................................... MX-806ALH audio processor ............ 3710-02-0806
U5 ..................................................................................... MX-805ALH sub-audio processor ...... 3710-02-0805
U6 ..................................................................................... LM386 audio amp ............................... 3410-01-0386
U7 ..................................................................................... LM7805 1A regulator ........................ 3400-08-7805
U8 ..................................................................................... LM7809CV 1.5A regulator ................. 3400-08-7809
U9 ..................................................................................... CD4094 shift register .......................... 3410-01-4094
U10 ................................................................................... 93C46 1Kbit Serial E²PROM.............. 3610-01-9346
U11 ................................................................................... MCP101-450 reset controller .............. 3410-11-0450
U12 ................................................................................... AT89C52-12JC Microprocessor ......... 3610-02-8952
U13 ................................................................................... LM321 opamp ..................................... 3410-12-0321
X1 ..................................................................................... 4.032 MHz HC18/U ............................ 6000-07-4032
VAR1 ............................................................................... 18V MOV ........................................... 2580-02-0018
Extruded aluminium case .................... 8100-01-5010
Aluminium end panel ........................... 8200-04-5010
ABS Plastic front panel....................... 8200-03-2502
TNC PCB mount RA connector ......... 7401-02-0007
10ft. radio cable with DB-9F conn. ..... 7500-10-1001
Shorting block for JP1 ......................... 7200-03-0102
TP1, RF Ant connection ..................... 7300-13-0101
Mounting bracket ................................ 9600-05-0001
RF interconnect board ......................... 9100-00-0001
4-40 SS jack screw ............................. 8000-42-4404
8-32 x ¼" SS philips ............................. 8000-24-8324
4-40 x 3/8" SS cap screw .................... 8000-34-4406
4-40 SS nut .......................................... 8000-54-4400
4-40 x ¼" SS philips ............................. 8000-24-4404
2-56 x 3/16" SS philips ......................... 8000-24-2563
4-40 x 3/16" SS philips ......................... 8000-24-4403
2-56 x 1/8" aluminium spacer ............. 8000-65-2562
Aluminium heat sink (U7 & U8) ......... 8400-05-0001
Right Angle heat sink (RF module) ..... 8400-05-0007