Pyramid Communications VR-100 User manual

VR-100
Vehicular
Repeater
15182 Triton Lane #102 Huntington Beach CA 92649
Revision D Aug 25 1994

Table of Contents
Specifications ..................................................................................... 1
Introduction ........................................................................................ 2
Functional Description ....................................................................... 3
Trunking Operation ........................................................................... 4
Installation .......................................................................................... 5
Jumper Selection ................................................................................ 5
Radio Connections ............................................................................. 6
Alignment ........................................................................................... 8
RF Alignment ..................................................................................... 8
Repeater Alignment ........................................................................... 9
CTCSS Table .................................................................................... 10
Figure 1 RF Test Points ................................................................... 11
Crystals ............................................................................................. 11
Figure 2 VR-100 Parts Locator ........................................................ 12
Parts List ........................................................................................... 13
Schematic ......................................................................... Fold Out
VR-100

Specifications
General:
Operation: Motorola PAC/RT® compatible plus trunking.
Modes: Priority, non-priority disabled, test mode.
Indicators: 8 high brightness LEDs, handheld queueing tones.
Interface: 9 pin "D" connector with 6 ft. cable.
Adjustments: Receive sensitivity, transmit dev., squelch threshold,
local mic sens., lock tone decode frequency, lock
tone dev., local speaker audio.
Jumpers: COR polarity, on-air polarity, enable/disable polarity,
Tx audio flat/de-emph., Rx audio flat/pre-emph.
CTCSS: DIP switch selectable, 37 EIA tones + 69.3 & 97.4
Power Requirements:
DC supply: 13.6 VDC ±25% negative ground.
Standby: 80 mA.
Receive: 250 mA.
Transmit: 1.5 A.
Physical:
Dimensions: 5.275"W x 6"L x 1.12"H.
Weight: 18 oz.
Case: One piece extruded aluminium.
Transmitter:
Frequency Range: 450-470 MHz
RF Power: 0.25-2W adjustable
Tx Spurious: -50dbc
Stability: 5ppm
FM Noise: -55db
Audio dist: <5%
Tx sens: 50mV-2.5V RMS
Lock Tone: Jumper selectable: 832.5 or 847.5Hz
FCC TA: LRUVR-100U Parts 22, 90
Receiver:
Frequency Range: 450-470 MHz
Sensitivity: .4μV for 12db Sinad
Mod Acceptance: ±7.5kHz
Selectivity: 70db
Spurious/image rej.: 60db
IMD response: 65db
Stability: 5ppm
Lock Tone detect: Tunable: 820 Hz to 930 Hz, 1% bandwidth
Local Rx Audio: 400mW into 8 Ohms
Specifications Subject to Change without notification
VR-100
Page 1

Introduction
The Pyramid Communications model VR-100 is a microprocessor
controlled low power vehicular repeater. It is designed to interface
between a high power mobile radio and a low power UHF handheld. If
the radio operator is out of the vehicle and the mobile radio is receiving
a transmission, the VR-100 will repeat the signal to the users handheld.
The user may also transmit back to the VR-100 via the handheld, and their
transmission will be repeated back to the base by the high power mobile
radio, effectively extending the range of the low power handheld.
On-board logic control by the microprocessor ensures that only one
vehicle will become active as the repeater, should several vehicles arrive
at the same scene. The logic also handles cases where the priority vehicle
leaves the scene (or fails), or another priority vehicle arrives from a
different site.
The model VR-100 is fully compatible with Motorola PAC/RT®
systems, as well as GE Ericsson and Standard EX-10/ CTS-20 radios.
Additionally, the VR-100 supports connection to LTR® or Motorola
trunking radios, local mic audio repeat (local PTT from the mobile is
repeated to the HT's), and local speaker audio for HT-Base transmissions.
Designed to interface to a wide variety of mobile radios, the VR-100
has input and output adjustments for Rx audio sensitivity, mobile Tx
deviation, COR polarity and threshold, local mic sensitivity, local speaker
audio, on-air detect polarity, enable/disable polarity and audio response
selections for flat or 6db/octave for both Tx and Rx audio paths. There
are also jumper selections for lock tone frequency, priority sample rate,
conventional/trunking operation and a built in test mode.
The eight LED front panel status indicators confirm proper CPU
operation, priority status, and mobile/repeater COR and PTT status.
VR-100
Page 2

Functional Description
The VR-100 operates on UHF simplex frequencies; the handhelds
transmit CTCSS but are carrier squelch receive. The VR-100 has CTCSS
on receive only. The repeater should be connected to a VHF high band
or low band mobile for best operation. Connection to a UHF mobile is
possible, provided there is enough separation in the mobile transmit and
the VR-100 receive frequencies. Also, antennas for the VR-100 and the
mobile radio should be located as far apart as practical, and with vertical
separation if possible. Additionally, bandpass filters and notch cavities
may be used to reduce interference between the mobile and VR-100.
When the user leaves the vehicle, they activate the VR-100 via their
mobile radio front panel or a separate switch. When the mobile radio is
receiving carrier and proper tone, the VR-100 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 VR-100 will
cease transmission periodically to check for handheld activity. If the VR-
100 detects proper carrier and tone from a handheld, it will key the mobile
radio and repeat the users transmission. In this way, the handheld is given
priority and may respond during repeater hang time. The VR-100 has a
3 minute time-out timer in the base to handheld direction. If the base
transmits to the mobile for more than 3 minutes, the VR-100 will send an
error tone to the handheld, unkey the repeater and remain idle until the
base ceases transmissions.
When the VR-100 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 handheld or handheld to
base transmissions. If another unit arrives at the same site and is
activated, it too will transmit the "lock tone"; when the first VR-100
detects the lock tone from the second unit, it will increment it's priority
counter and will no longer repeat any transmissions. This process will
continue for each unit that arrives at the scene, creating a priority
hierarchy for up to 256 vehicles.
Even though the other VR-100's 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 decrementing their priority
counters until one of them reaches the priority status and begins repeating
VR-100
Page 3

the transmission. Since the VR-100's are all at different priority counts,
only one will reach priority status and begin transmitting. The other units
will sense the priority repeater and cease decrementing their counters,
preserving the priority hierarchy.
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 VR-100's unkeys to check
for handheld activity, it will detect the presence of the other active
VR-100 and increment it's priority counter and cease transmission.
This is the self clearing mode to prevent radio "collisions".
If the user were to key the mobile radio locally and his VR-100 is
the priority, the VR-100 will detect the local mic PTT and repeat the
transmission to the other handhelds at the site so that they would not
miss half of the transmission.
If the users wish to communicate HT-HT without accessing the
mobile repeater, they may transmit on the same frequency without
CTCSS encode. The repeater will only respond to carrier andtone from
the handhelds.
TrunkingOperation
When the model VR-100 is connected to a trunking radio and the
user wishes to access the system from the handheld, they key their
handheld briefly then release. The VR-100 will key the mobile radio
for 200mS, during which time it monitors the mobile's transmitter for
an on-air condition. If it does not see the radio transmit at all (system
is busy), it will retry every 5 seconds until successful or time out (30
Sec). It will also send a "busy" tone to the handheld every 5 seconds to
indicate the progress of the call attempt. If unsuccessful after 30
seconds, the VR-100 will transmit an error tone to alert the user that the
call attempt failed.
When the VR-100 detects that the mobile is transmitting, it will
continue to monitor the on-air line until the transmitter remains
keyed for at least 250 mS to ensure that the radio is not 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 user. 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 VR-100 will unkey the
mobile and send the error tone as before.
VR-100
Page 4

Installation
Before installing the VR-100, ensure that the RF and repeater
sections are properly aligned per the tuning procedure beginning on page
8 of this manual. Additionally, ensure that the VR-100 jumpers are
properly configured for use with the particular mobile radio that it will be
connected to:
JP1 Controls the polarity of the remote enable/disable feature of the
VR-100. If the remote enable line (pin 3 of P1) goes low to
activate the repeater, set JP1 to the (-) position. If pin 3 goes high,
set JP1 to the (+) position. If pin 3 is not used and you wish to
have the repeater active at all times set JP1 to the (-) position and
ground pin 3.
JP2 Controls the polarity of the mobile COR line. Before setting this
jumper, COR threshold adjustment (RV5) should be made as
described in the alignment section of this manual on page 9. If
the mobile COR line goes more positive in the presence of
carrier, set JP2 to the (+) position or to the (-) position if the line
goes more negative during carrier.
JP3 Controls the polarity of the on-air detect line (pin 9 of P1). This
line is only used in trunking applications. If the transmitter
sense line goes more positive during transmit, set JP3 to the (+)
position, otherwise set JP3 to the (-) position. Ifusingatrunking
radio, ensure that JP6 is also shorted.
JP4 Controls the audio response of the mobile transmit signal. If
pin 2 of P1 is connected to the mobile transmitter audio path
before pre-emphasis, JP4 should be set to de-emph. in order to
correct for the pre-emphasized audio coming from the handheld.
If pin 2 is connected after pre-emphasis, set JP4 to flat.
JP5 Controls the VR-100 lock tone encode frequency. If JP5 is open
(default) the lock tone frequency is 832.5 Hz. If JP5 is shorted,
the lock tone frequency is 847.5.
JP6 If the VR-100 is connected to a conventional radio, leave JP6
open. If connected to a trunking radio, short JP6. If JP6 is
shorted, ensure that pin 9 of P1 is connected to a point in the radio
that indicates the radio is transmitting and ensure that JP3 is
configured properly.
VR-100
Page 5

JP7 During base to handheld transmissions, the VR-100 will
periodically unkey the repeater to check for handheld activity.
JP7 enables the priority sampling. If open, the VR-100 will not
priority sample. If JP7 is shorted, the VR-100 will sample at 1
second intervals.
JP8 Used only for testing and alignment of the VR-100. If shorted,
the VR-100 transmitter is active and the lock tone is sent
continuously. For normal operation, ensure that JP8 is open.
JP9 Controls the audio response of the repeater transmit signal. If
pin 6 of P1 is connected to the mobile's discriminator or a point
in the receiver before de-emphasis, JP9 should be set to flat. If
pin 6 is connected after de-emphasis, set JP9 to pre-emph. in
order to correct the audio for the handheld receiver.
Make the connections between the mobile radio and the VR-100
cable as follows:
Pin 1: Ground. Connect the 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
JP4 is set to de-emph. If connected after pre-emphasis, set JP4
to flat.
Pin 3: Remote enable/disable. Connect to the radios 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. If not used ground pin 3 and set JP1 to the (-)
position; the repeater will be active any time there is 12 VDC at
pin 5.
Note: This line does not have a pull up resistor; if connected to
an open collector or dry contact output, add a 10K resistor
between pin 3 and pin 5 of P1 on the VR-100 main PCB.
Pin 4: Mobile PTT output. Connect to mic PTT on the mobile radio,
or a line that goes active low to transmit. This line is also used
to sense local mic PTT in order to repeat the local mic audio to
the handhelds.
Note: To disable local mic repeat, remove D4.
Pin 5: 12 VDC input. Connect to the radio's switched 12V supply.
(Blue)
(Black/Shield)
(Green)
(Red)
(White)
VR-100
Page 6

Pin 6: Mobile receiver audio. Connect this line to the mobile receive
audio path before the volume control. If pin 6 is connected before
de-emphasis ensure that JP9 is set to flat. If pin 6 is connected
after de-emphasis, set JP9 to pre-emph.
Pin 7: Mobile COR detect. This line is used to indicate when the
VR-100 should repeat the transmission to the handheld. Connect
to a logic point in the mobile that indicates proper tone and
carrier have been detected or the audio unmute line. If this line
goes more positive during an unmute condition, set JP2 to the (+)
position. If pin 7 goes more negative during unmute, set JP2 to
the (-) position. RV5 should also be set for the midway voltage
between mute and unmute. Example: If connected to a logic line
that goes between 0 and 5 VDC, set RV5 (pin 12 of U3) for 2.5
V. If pin 7 goes between 5.6 and 7.2 VDC, set RV5 for 6.4 VDC.
Pin 8: Local mic audio. When the user keys the mobile radio and the
VR-100 connected to it is the priority unit, the local mic audio
can be repeated to the handhelds. Connect this line to a point in
the mobile transmitter audio path after pre-emphasis but before
limiting or filtering. RV6 sets the sensitivity level.
Note: To disable local mic repeat, remove D4.
Pin 9: On-air detect. Used only in trunking applications to indicate
when the mobile transmitter is actually on the air. This is not the
same as mobile PTT. Connect radio PTT on the logic board or
to switched transmitter B+. If pin 9 goes positive during
transmit, set JP3 to the (+) position. If pin 9 goes to ground
during transmit, set JP3 to the (-) position.
Install the VR-100 in the vehicle using the supplied mounting
bracket and hardware. The bracket is secured to the housing using four
8-32 x ¼" machine screws. Do not use screws longer than ¼" for
mounting the VR-100 to the bracket or circuit damage may result.
(Brown)
(Violet)
(Yellow)
(Grey)
VR-100
Page 7

Alignment
In order to properly align the VR-100, you will need two service
monitors and the mobile radio that the repeater will be installed with.
Refer to figures 1 and 2 for alignment points.
Dis-assemble the repeater by removing the two allen-head screws on
the rear panel, the phillips screw on the bottom and sliding the main
circuit board out of the housing with the rear panel attached. Connect one
service monitor to the VR-100 BNC jack and the other to the mobile
antenna jack; connect the cable from the mobile radio to the VR-100.
Turn on the mobile and active the VR-100. Adjust the squelch control on
the RF board (R115) so that the repeater COR LED on the front panel is
off.
RF Alignment
Important: The case of the VR-100 is integral to the heat sink for the RF
module and voltage regulators. Do not transmit at full power for extended
periods of time with the PCB removed from the case or damage may result!
1. Short jumper JP8 on the VR-100 main PCB. With a DC voltmeter
at TP01 on the RF board, adjust L203 and L204 for a maximum
reading.
2. Move the voltmeter to TP02 on the RF board; adjust L203, L204,
L205 and L206 for a maximum reading.
3. Move the voltmeter to TP03 on the RF board; adjust L205, L206,
L207 and L208 for a maximum reading.
4. Move the voltmeter to TP04 on the RF board; adjust R232 to midway.
Adjust C244 and C247 for a minimumreading at TP04. Adjust R232
for 2 Watts. Adjust C205 for the transmit frequency ±100 Hz.
Remove the short from JP8 on the VR-100 main PCB.
5. Set the service monitor connected to the VR-100 to generate the
repeater receive frequency with a 1kHz tone at ±3kHz deviation.
Connect a Sinadder to TP 1 on the VR-100 main PCB. Adjust the
signal generator output level for a reading of 12db Sinad.
6. Adjust L112, L113, C147, C151, L101, C104 and L104 in that order
for a maximum Sinad reading at TP 1. Re-adjust the signal generator
output level as necessary to maintain a usable reading.
7. Adjust C136 on the RF board for a maximum Sinad reading.
VR-100
Page 8