Motorola 92FT4848, 92FT3802, 92FT4849 User Manual
PRELIMINARY USERS MANUAL
Model Chart for the Vehicular Repeater System Model 750
Model Number
P2080A
Item Number
X X X HHN4044A VRS 750 Housing
X X X HLN6855A VRS 750 Mounting Assembly
X X X PLN7780A VRS 750 Controller Board
X X X HLN6856A XCVR Hardware
X PUD1001A VHF Transceiver
X PUE1036A UHF R1 Transceiver
X PUE1037A UHF R2 Transceiver
Note 1 Note 1 Note 1 HKN6153A Cable, Mobile-to-VRS
Note 2 Note 2 Note 2 HKN6154A Cable, Siren-to-VRS
Note 3 Note 3 Note 3 6881094C84 VRS 750 Detailed Service Manual
X X X 6881087C79 Safety Pamphlet
X X X 2884606M01 Mini-UHF crimp connector
X X X 3305873U04 Chassis Label
X X X Front Label
X X X XCVR Label
X X X Packing Kit
3085031D02 Cable, VRS Programming (optional)
NTN4056A Adapter, VRS Flash programming (optional)
NKN6460A y-cable kit for dual controlhead w/vrs (optional)
TLN5277B DC filter for excessive alternator whine (optional)
Global Tuning Tool - CD ROM (optional)
Note 1
Note 2
Note 3
ASTRO Spectra Compatible VRS Model 750 (136-174 MHz)
P2081A
With option xxxxA
With option xxxxB
One item per 10 units
ASTRO Spectra Compatible VRS Model 750 (403-470 MHz)
P2082A
ASTRO Spectra Compatible VRS Model 750 (450-512 MHz)
Description
Description
VRS750 SPECIFICATIONS- VHF
GENERAL TRANSMITTER RECEIVER
Model: P2080A (136 – 174 MHz)
RF Power Out: Intermodulation per EIA:
Number of Channels: 1, T1=R1
Frequency:
Programmable, Synthesized
Frequency Channel
Channel Spacing:
12.5/20/25 kHz
Operation Temp. Range:
-30°C to +60°C
Primary Power: Modulation Limiting(max): Conducted Spurious Rejection:
13.8 VDC ± 20%, Negative Ground ±2.5 kHz @ 12.5 kHz
DC Current Drain(max):
120mA Receive +1, -3 dB 60 dB @ 12.5 kHz
500mA Transmit @ 275mW 70 dB @ 25/30 kHz
1.10A Transmit @2W
3% Typical @ 1 kHz, 60%
Squelch Operation:Private-Line
required for repeater access
FM Hum and Noise: -40dB
Duty Cycle: Intermittent per EIA at
275mW
TX Attack Time: 32 ms
PPI Sample time: 16ms Typical Conducted Spurious Emissions:
275 mW to 2 W tunable 70 dB
Spurious and Harmonic
Emissions:
-36 dBm < 1 GHz
-30 dBm > 1 GHz
Frequency Stability: Reference Sensitivity(typical):
±2.5 ppm @ 25 kHz
±2.5 ppm @ 12.5 kHz
±4.0 kHz @ 20 kHz
±5.0 kHz @ 25 kHz
Audio Response: (from
6dB/octave pre-emphasis, 300
to 3000 Hz)
Audio Distortion:
maximum deviation
+1 to –3 dB
Typical
Hum and Noise:
-40dBm @ 25 kHz
-35dBm @ 12.5 kHz
0.28µV (-118dBm) at 12 dB
SINAD
70 dB
Adjacent Channel Selectivity:
Audio Response (0.3 – 3 kHz):
Audio Distortion
3% Typical @ Mobile Rated
Audio*
Singletone Encoder/Decoder:
Nominal 847. 5 Hz Antenna connector: mini-uhf
RX Attack Time: 60ms Typical
FCC Identifiers:
AZ492FT3802 (P2080A)
Industry Canada:
* Typically 5W in 8 ohms
Antenna Impedance: 50 ohms -57dBm <1GHz
-47dBm > 1GHz
VRS750 SPECIFICATIONS-UHF
GENERAL TRANSMITTER RECEIVER
Model: P2081A (403 – 470 MHz)
P2082A (450 – 512 MHz)
Number of Channels: 1, T1=R1
RF Power Out: Intermodulation per EIA:
275 mW to 2 W tunable 70 dB
Frequency:
Programmable, Synthesized Frequency
Channel
Channel Spacing:
12.5/20/25 kHz
Operation Temp. Range:
-30°C to +60°C
Primary Power: Modulation Limiting(max): Conducted Spurious Rejection:
13.8 VDC ± 20%, Negative Ground ±2.5 kHz @ 12.5 kHz
DC Current Drain(max):
120mA Receive +1, -3 dB 60 dB @ 12.5 kHz
700mA Transmit @ 275mW 70 dB @ 25/30 kHz
1.20A Transmit @2W
3% Typical @ 1 kHz, 60%
Squelch Operation: Private-Line
required for repeater access
FM Hum and Noise: -40dB
Duty Cycle: Intermittent per EIA at
275mW
TX Attack Time: 14 ms Typical
Spurious and Harmonic
Emissions:
-36 dBm < 1 GHz
-30 dBm > 1 GHz
Frequency Stability: Reference Sensitivity(typical):
±2.5 ppm @ 25 kHz
±2.5 ppm @ 12.5 kHz
±4.0 kHz @ 20 kHz
±5.0 kHz @ 25 kHz
Audio Response: (from
6dB/octave pre-emphasis, 300 to
3000 Hz)
Audio Distortion:
maximum deviation
+1 to –3 dB
Hum and Noise:
-40dBm @ 25 kHz
-35dBm @ 12.5 kHz
0.28µV (-118dBm) at 12 dB
SINAD
70 dB
Adjacent Channel Selectivity:
Audio Response (0.3 – 3 kHz):
Audio Distortion
3% Typical @ Mobile Rated
Audio*
PPI Sample time: 16ms Typical Conducted Spurious Emissions:
Singletone Encoder/Decoder:
Nominal 847. 5 Hz Antenna connector: mini-uhf
RX Attack Time: 60ms Typical
FCC Identifiers:
AZ492FT4848 (P2081A)
AZ492FT4849 (P2082A)
Industry Canada:
Antenna Impedance: 50 ohms -57dBm <1GHz
-47dBm > 1GHz
* Typically 5W in 8 ohms
List of Abbreviations and Acronyms
B-P Base to Portable
CPS Customer Programming Software
DPL Digital Private Line
HT750 Transceiver internal to VRS750
HUB Hang Up Box
ICM In Car Monitor
ms Millisecond
PAC Portable Area Coverage
PL Private Line
PPI Portable Priority Interrupt
P-B Portable to Base
RF Radio Frequency
RX Receive
SB Serial Bus
SBEP Serial Bus Expanded Protocol
Slm-net Transceiver internal to VRS-EP
TOT Time Out Timer
TX Transmit
VIP Vehicle Interface Port
VRS Vehicular Repeater System
VRS-EP Vehicular Repeater System - Expanded Protocol
VRS750 Vehicular Repeater System - Model 750
1. Introduction
Description
The ASTRO Spectra compatible Vehicular Repeater System - Model 750 (VRS750) is a
mobile radio system component that provides on-site repeater capability between a
portable radio and a base station. The VRS gives the portable user the equivalent range of
a mobile radio with the flexibility of a portable. The VRS is not an ASTRO-capable
radio; instead, it is designed to interface with an ASTRO Spectra mobile radio. It can
only transmit and receive clear analog transmissions.
The VRS receives transmissions on the portabl e radio's transmit frequency with the
proper access PL, and passes these portable signals to the mobile radio. The mobile radio
re-transmits the signals to the base station on the mobile radio's transmit frequency.
NOTE: These transmissions have the mobile's ID, not the portable's.
Similarly, base station signals received by the mobile radio are sent to the VRS and retransmitted to the portable radio. The VRS does not provide local repeater capability
(received portable signals are not repeated on the portable receive frequency).
The VRS-to-portable and portable-to-VRS communications are limited to clear analog
only. This is a simplex-only interface; the VRS cannot receive and transmit
simultaneously. The base station-to-mobile and mobile-to-base communications protocol
is not limited to analog only. Rather, this interface is limited by the features and functions
of the ASTRO Spectra and the base.
Ordering Infor mati o n
The VRS is a crossband repeater that operates on either UHF or VHF frequencies. The
repeater cannot be operated with a mobile radio operatin g in the same band as the VRS
unit.
The VRS RF platform is based on the HT750 synthesized transceiver. The VRS supports
one channel whose frequency and channel spacing can be programmed in the field. The
VRS remains a simplex repeater and as a result, the transmit frequency must be set equal
to the receive frequency. The VRS receives its programming information from the
ASTRO Spectra mobile at power-up. The ASTRO Spectra mobile supports the VRS
programming fields via ASTRO Customer Programming Software (CPS). For more
information, refer to “Programming,” Chapter ?.
The VRS is not compatible with ASTRO Spectra mobiles with the VSELP signaling
type.
When integrating a VRS with an ASTRO mobile with a Siren/PA, an additional interface
cable is needed (?). This cable allows the VRS to be connected to the Siren /PA. For more
information, refer to "Installation," Chapter 4.
When integrating a VRS with an ASTRO mobile with Dual Control heads, an additional
interface cable is needed (NKN6460A). This y-cable allows the VRS to be connected to
the ASTRO mobile with two control heads. For more information, refer to "Installation,"
Chapter 4.
A separate antenna (not included) is necessary for use with the repeater. Typically, a onequarter (1/4) wave length antenna maximizes radiation efficiency when installed at the
center of the vehicle roof. If it is necessary to mount the antenna on the vehicle’s trunk
lid, an appropriate 3dB gain antenna should be used. See "Installation," Chapter 4, for
details.
A filter for the battery lines (TLN5277B)is available for use with ASTRO Spectra
mobiles. This filter can be used to prevent excessive alternator whine noise from being
heard on the mobile speaker during VRS operation.
The VRS ships from the factory with the low output power setting at 275mW and a high
output power setting of 2W. The low output power setting is the default setting. We
recommend the LOW Transmit Power setting of 275mW for optimal performance. This
output power provides the VRS with a simi lar range as the portable when attached to a
mobile antenna. Any deviation from this setting could result in a loss of communication
from the portable to the base.
The Global Tuning Tool (not included) can be used to tune the VRS output power in the
field. For more information refer to “Tuning,” Chapter ?.
VRS Features
The VRS operates with the ASTRO mobile radio and contains the following integrated
features:
o Automatic, multiple-unit, priority-resolution algorithm.
o Portable priority interrupt (PPI) function.
o Conventional/trunked operation.
o Remote switch enable/disable capability for control charger interface.
o Remote activation of emergency alarm feature.
o In-car monitor operation.
o VRS mobile access tones.
o Mobile radio transmitter steering of up to eight modes via Private-Line (PL) code
transmission from the portable radio.
o TX PL generator.
o Base repeater operation for two-frequency, simplex, fixed-repeater systems.
o Mobile audio repeat.
All VRS features can be programmed in the field using ASTRO Spectra mobile CPS.
For more information, refer to “Programming,” Chapter ?.
IMPORTANT NOTE: All ASTRO Spectra VRS systems with the same VRS RF
transmit/receive frequency need to be CPS programmed identically to ensure proper
operation. Failure to do so could result in erratic system operation.
The VRS does not have to be installed in the system for programming - only the mobile
radio is programmed. If the VRS is not connected after programming the m obile system,
an error message "ERR 12/10" will be displayed on the control head.
Mutually-Exclusive Features
The VRS IS NOT compatible with the following mobile radio features:
o W3 Control Head is not supported with VRS
o VSELP signaling type
o Data-VRS and data are not compatible on the same channel and cannot be
used simultaneously. VRS should never be activated on a channel that has
packet data enabled, and VRS mode steering channels should not have
packet data enabled.
o Scan
o Over-the-Air Rekeying (OTAR) Rekey Request
o Message (from the Control Head)-Trunking or Conventional
o Status (from the Control Head)-Trunking or Conventional
o Emergency Call-Trunking or Conventional-Emergency Call and VRS are
mutually exclusive. Even if the mobile is programmed for Alarm and Call,
when the Alarm case is exited, the mobile will not transition into
Emergency Call while the VRS is activated. Likewise, if the mobile is in
Emergency Call, the VRS cannot be activated. NOTE:When an
Emergency Alarm is received, the dispatcher may elevate that talkgroup to
Emergency status.
o Reprogram Request-Trunking
o Repeater Access Control-Conventional
o Mobile Single Tone-Conventional
o Seven-Tone Modat-Conventional
o Motorcycle
o Consolette (Digital Remote and Tone Remote)
The following mobile radio features may be received but may not be initiated
or responded to while VRS is enabled.
o Private Conversation -Trunking
o Call Alert-Trunking or Conventional
o Telephone Interconnect-Trunking or Conventional
o Voice Selective Call-Conventional
2. VRS Operation
General
The VRS is a crossband repeater that repeats either UHF or VHF portable transmissions
though a VHF, UHF, or 800MHz ASTRO mobile. The repeater cannot be operated with a
mobile radio operating in the same band as the VRS unit. In multiple-VRS sites, the VRS
uses a priority algorithm to prevent other VRS units from repeating. In this mode, only
the highest priority VRS will serve multiple portable users. This prevents interference
problems associated with multiple VRS units in proximity to one another.
Control Unit
The VRS may be enabled/disabled from the ASTRO mobile radio's remote-mounted W4,
W5, W7, or W9 control head (see Figure 1). The VRS button may occupy any of the
indicator button positions. Field programming determines the exact position. The VRS
requires an ASTRO radio with a remote-mount control head.
Figure 1 Typical ASTRO Control Head with VRS
When the VRS is turned on, the indicator illuminates and, after transmitting the Single
Tone burst, the words "VRS BOTH" (indicating the In-Car Monitor mode) will be
displayed momentarily. The indicator remains on for as long as the VRS is on.
When the VRS unit is activated, it transmits Single Tone on the portable frequency, and
assumes the priority (active) repeater state. The Single Tone frequency is fixed at 847.5
Hz. For proper operation, all VRS units to be used in the same system must be
programmed with the same Single Tone frequency, as well as other VRS and ASTRO
mobile features.
Press the VRS button to disable the VRS option. When the system is turned off and then
back on from the control head, the VRS opt ion returns to the state it was in immediately
before the control head was turned off.
Vehicle Interface Ports
Another method of enabling/disabling the VRS option is through the use of a vehicle
interface port (VIP). The field programmer selects which VIP to use and whether the
input control voltage is to be high/ground or ground/high.
One use of VIP operation connects the VRS switch lead to a portable radio vehicular
control charger, such as the AVA, SVA, MVA, or MTVA. Remove the portable from its
charger pocket to automatically enable the VRS option. Replace the portable unit in its
charger to disable the VRS option. A toggle switch on the portable unit charger allows
the portable unit to be removed without enabling the VRS option.
NOTE: This requires an additional field modification kit, PLN1334A, which is not
included with the VRS.
Turning the portable unit charger off, then on does not disable the VRS option. The VIP
setting controls the on/off state of the VRS option. If the field programmer chooses the
VIP option, pressing the VRS button on the control head will only cause the display to
change momentarily to the In Car Monitor Mode ("VRS BOTH"). It will not enable or
disable the VRS as previously described. It is still necessary, however, to select in
CPSCPS an indicator button for the VRS if it is desired to have the indicator light when
the VRS is enabled.
VRS Access
With the VRS on, press the portable radio's PTT button to begin transmissions. The VRS
programming must include correct PL frequencies to allow the portable unit to access the
option. The
VRS option receives signals with the correct PL, then uses the mobile radio to re-transmit
the signals. The control head's XMIT indicator lights during the re-transmission.
The VRS re-transmits received mobile si gnals as explained in the "Mobile Audio Repeat"
paragraph on page 7. Note that the XMIT indicator does not light when the VRS is
transmitting to the portable.
To transmit directly to the other portable units, turn off the portable transmit PL. This
allows you to talk around the VRS without transmitting on the mobile channels.
In-Car Monitor
The "In-Car Monitor" (ICM) feature is for use in a two-man operation where one use r
(user 1) is out of the vehicle while the other (user 2) remains in the vehicle. This allows
user 2 limited access to both mobile and portable communications when the VRS is on,
even when the repeater is the priority unit. ICM operation is set to BOTH.
ICM Transmissions
VRS BASE:
Press the mobile's PTT to transmit on the frequency corresponding to the mode shown on
the control head’s display. If this mobile’s VRS is the priority unit (in delay state zero),
the VRS unit will then become non-priority upon the mobile PTT. If you press the
mobile's PTT during portable-to-base VRS activity, a talk-prohibit tone sounds and the
mic audio is disabled.
VRS BOTH:
Press the mobile's PTT to transmit simultaneously on the frequency corresponding to the
mode shown on the control head's display, and the portable frequency. Use the ASTRO
CPS to enable the VRS TX PL generator option to transmit with the proper PL frequency.
If you press the mobile's PTT during portable-to-base VRS activity, a momentary talkprohibit tone sounds and the microphone audio is disabled.
When using VRS BASE or VRS BOTH mode, all mobile transmissions are on the mode
that is shown on the control head's display. If the VRS is currently steering to another
mode, that steered mode will be displayed on the control head. Any mobile transmissions
will be on that new mode until the portable steers the VRS back or the mode rocker
switch is used to change modes. If the mode rocker switch is used to change modes, the
portable user will not be made aware of this mode change. With Ack Tones are enabled,
the portable user will hear a "bad" tone if the mode is changed during the transmission.
VRS Reception
The VRS option has no effect on mobile radio squelch control or normal mobile radio
reception. The VRS portable unit's squelch setting is not user adjustable. Portable audio is
heard from the mobile speaker of the priority VRS unit as shown in the following table:
Mobile Microphone Portable Audio Heard from Mobile Speaker
On HUB PL*
Off HUB CSQ
* = any valid repeater access PL
Repeated portable transmissions will always be heard from the mobile speakers.
Portable transmissions without proper PL will only be heard from the mobile speaker if
the microphone is off HUB.
Mobile Audio Repeat
The VRS transmits to the portable when audio unmutes the mobile speaker. This allows
the user to set the monitor button "on" to defeat the coded squelch requirements of the
mobile radio on a base-to-portable transmission or "off" to prevent the VRS from
repeating base-to-portable (HUB will also disable this), unless the coded squelch
requirements of the mobile radio are met. Button presses (that is, Volume, Mode, etc.) on
the priority mobile unit will also be transmitted by the VRS.
3. Operation of VRS
Options
The following sections describe the operation of CPS field-programmable options of the
VRS. This includes information about when to use an option and compatibility between
options.
Base Repeater
For two-frequency simplex systems using a fixed-site repeater, you can enable the base
repeater option. This adds 300 ms of delay to the prioritization routine to account for the
fixed repeater attack time. This allows non-priority mobiles to detect any priority mobile
in the system through the base repeater.
Mobile Detector
The Mobile Detector feature allows the user to operate VRS units with two-frequency
simplex dispatch systems without a base repeater. This feature allows the automatic
multi-unit priority resolution algorithm to function in the above scenario. When this
feature is activated by the CPS, a non-priority VRS will send a message to the mobile to
enable a "Listen Around" feature when a proper po rtable PL is received.
"Listen Around" switches the mobile radio's receive frequency to match that of its
transmit frequency of the steered mode. The non-priority VRS will count down in priority
if its corresponding mobile does not detect the repeated transmission on the "Listen
Around" frequency. When the portable is dekeyed, the non-priority VRS will send a
second message to the mobile to disable "Listen Around" and return to normal operation.
This feature does not use any additional user modes in the mobile.
NOTE: The Mobile Detector feature only works on conventional modes. Trunked
modes will be unaffected.
VRS Transmit PL Generator
The transmit PL generator, when enabled, causes the VRS to transmit (base-to-portable),
with specific field programmable PL tones. The selected VRS transmit PL frequency
cannot be the same as any of the VRS receive PL frequencies that the portable uses to
access the vehicular repeater.
VRS Mode Steering
The VRS steering option gives the portable operator the ability to select the current
mobile radio mode via PL tones. The total number of Mode-Steered modes can not
exceed eight (including emergency, message, and status). The operator may program as
many as eight such tones, along with corresponding mobile mode numbers, into the
VRS. The portable operator sets the channel or mode select switch to the position
corresponding to the desired mobile mode and keys up the portable. The VRS unit
decodes the PL tone and steers the mobile radio to the desired mode. There are two types
of steering supported: Transmitter Steering/Receiver Latching, and Transmitter
Steering/Receiver Steering.
NOTE: If mode steering is not selected during CPS programming, the programmer
will need to enter the repeater access PL, which corresponds to a single access PL with
select mode steering.
Steering Types
o <Transmitter Steering/Receiver Latching> - On portable-to-base repeating, the
mobile radio is steered to the proper mode as determined by the received PL from the
portable. When the portable dekeys, the condition to repeat ceases, and the mobile radio
remains on this mode. Thus, all future base-to-portable repeating is heard via the mobile
mode last steered by the portable.
The mobile control head will display the steered/latched mode. If, sometime after
this operation and while no repeat is occurring, the ICM user keys the mobile with the
micropnone's PTT button, the mobile will now transmit on the latched mode that is
displayed on the control head. If, however, the in-car-monitor (ICM) user changes the
selected mode using the mobile's mode rocker switch before pressing the mic PTT, the
mobile will now transmit on the new selected mode.
NOTE: For the above type of steering, the portable user will be able to steer back
to the selected user mode on the control head by programming one PL destination for
Sel-Mode. However, the selected mode can be changed by the rocker mode switch.
o <Transmitter Steering/Receiver Steering> - On portable-to-base repeating, the
mobile radio is steered to the proper mode as determined by the received PL from the
portable. When the portable dekeys, the condition to repeat ceases, and the mobile radio
remains on this mode for 6 seconds. During this 6 seconds, the VRS waits for a
repeatable base-to-portable transmission to be received.
• If a base-to-portable transmission is not received, the mobile will return to the last
mode selected by the control head's rocker switch (current user-select ed mode).
• If a base-to-portable transmission is received during the 6-second timer, the timer
will be reset back to 6 seconds and start over at the end of the transmission.
• If the portable is keyed during the 6 seconds, the VRS will handle the destination
PL accordingly and reset the timer. If the 6-second timer has not expired, no
repeat is occurring, and the ICM user keys the mobile with a microphone PTT, the
mobile will transmit on the steered mode and the 6-second timer will start over at
the end of the transmission.
Steering Destination Types
There are five types of actions, or "steering destination types," that the VRS can be
programmed to perform as a result of receiving a portable transmission with the specified
PL:
NOTE: Each receive PL can only be used once and can only be programmed with
one type of steering destination (for example, a single PL cannot be programmed to both
change the mobile mode and send a message.)
Zone/Chan
The VRS will command the ASTRO mobile to change to the mode programmed by the
CPS. Once the mobile has steered, it will follow the conventions of the type of steering
selected (for example, Transmitter Steering/Receiver Latching).
Select Mode
The VRS will command the ASTRO mobile to return to the last mode selected by the
rocker switch on the control head. If the portable user has steered to another mode, and
the selected mode is changed in the car, the steering will be canceled until the VRS
receives another mode steering PL.
Emergency Alarm
The VRS will initiate an Emergency Alarm through the ASTRO mobile, if the mobile is
programmed for this type of Emergency, in the same manner as if the Emergency button
on the control head were pressed. The type of Emergency (trunked or conventional)
depends on the currently selected mobile mode, (trunked or conventional, respectively).
The VRS will only generate an Emergency, not perform a portable-to-base audio repeat,
while the portable is transmitting on an "Emergency request" channel. This feature is
typically implemented in the portable, using a one-touch button that has been
programmed for Emergency-revert to a channel with the proper PL.
Although the portable generates MDC tones, the VRS cannot decode MDC. Instead it
responds to the PL of the portable mode on which the Emergency MDC tones are
transmitted. All of this is transparent to the user.
Message
The VRS will command the ASTRO mobile to send out an CPS-programmed message on
the mode currently displayed on the control head, in the same manner as if the request to
send a message had been generated using the control head. The VRS will send out only
one message per received portable signal. No mode steering will occur; the currently
steered/latched mode and the selected mobile mode will remain as they were before the
request to send a message was received.
If the message selected is valid, the VRS will transmit to the portable the mobile tones
indicating whether or not the valid message was acknowledged. If the message selected is
invalid, (either incorrectly programmed in CPS or not a valid message for the currently
displayed mode), the VRS will send a low-pitched alarm tone to the portable.
To generate a message request, the portable user would:
o select the channel on the portable programmed for the message request,
o momentarily press the PTT button,
o wait for the confirmation tone, and
o return the channel selector to a voice channel.
The VRS will not perform a portable-to-base audio repeat while the portable is
transmitting on a "message request" channel.
NOTE: A message cannot be generated from the control head while the VRS is
activated.
Status
The VRS will command the ASTRO mobile to send out an CPS-programmed status on
the mode currently displayed on the control head, in the same manner as if the request to
send status had been generated using the control head. The VRS will send out only one
status per received portable signal. No mode steering will occur; the currently
steered/latched mode and the selected mobile mode will remain as they were before the
request to send a status was received.
If the status selected is valid, the VRS will transmit to the portable the mobile tones
indicating whether or not the valid status was acknowledged. If the status selected is
invalid, (either incorrectly programmed in CPS or not a valid status for the currently
displayed mode), the VRS will send a low-pitched alarm tone to the portable.
To generate a status request, the portable user would:
o select the channel on the portable programmed for the status request,
o momentarily press the PTT button,
o wait for the confirmation tone, and
o return the channel selector to a voice channel.
The VRS will not perform a portable-to-base audio repeat while the portable is
transmitting on a "status request" channel.
NOTE: A status cannot be generated from the control head while the VRS is
activated.
Time-Out Timer
The Time-out Timer (TOT) duration value sets the maximum allowable time for a baseto-portable transmission. The VRS TOT may be set to 30, 60, 120 seconds, or disabled.
When a unit times out, it counts up to delay state one. This removes it as the priority unit.
VRS Single Tone
When the VRS unit is enabled, it transmits an audible tone (Single Tone) for 700 mS
which is used by other VRS units for the automatic prioritization routine. The Single
Tone frequency is fixed at 847.5 Hz.
VRS Mobile-TX Acknowledgment Tones (Conve ntional Only)
When this option is enabled, the VRS transmits a 750 Hz feedback tone after it has
received a repeatable message on the portable frequency. This signals the portable
operator that the transmission was received. If the repeated message was cut short due to
the mobile TOT being exceeded or the mobile channel being changed during the repeat, a
lower-pitched tone (304 Hz) sounds. If the portable user does not hear a tone after
completing a transmission, the portable is either out of range of the repeater or there is no
priority repeater in the area.
See "VRS Mobile Trunking Tones (Trunking Only)" on page 26 for a description of
trunking acknowledgment tones.
Flashing Display
The Flashing Display feature causes the di splay on the control head to alternate between
the current mode and "VRS BOTH." This feature is used primarily when the VRS
enable/disable button does not have an indicator light or when VIP activation is used.
This feature is normally disabled in CPS. The length of time "VRS BOTH" is displayed
every 6 seconds is determined by the "temporary message display timer" value. This
value (from 250 to 6250 ms [default = 1000 ms]) can be programmed by the CPS. It is in
the RADIO WIDE DISPLAY OPTIONS screen (D, C, F from the main CPS screen).
Repeater PPI
The Repeater Portable Priority Interrupt (PPI), when enabled, causes a base-to-portable
transmission to be interrupted every 1 second in trunked mode or 2 seconds in
conventional mode so that the repeater can search for a portable radio signal. (These
times are programmable and may be changed to 500ms for trunked or 500ms for
conventional modes). This interruption may be heard on the portable as a "clicking"
noise, but PPI is necessary to give the portable user priority over base-to-portable
transmissions, for the self-clearing function of the automatic priority resolution feature,
and to allow portable users in trunked mode to break in during system hang time to
prevent loss of voice channel. This feature may be disabled through CPS.
Quick-Key
This feature allows the portable user to determine the status of the mobile trunking
system. The feature is initiated by a short press of the portable's PTT that is long enough
for the VRS to key the mobile and access the trunking system, for less than 1 second in
duration.
4. Installation
When selecting the location for the VRS, make certain that there is sufficient clearance
for routing the T-cable and the antenna cable to the front of the unit.
VRS Installation
The standard VRS is installed using the HKN6153A interface cable. The molded DB-25
end connects to the ASTRO front connector. The DB-25 end with the plastic jacket
connects to the VRS (see Figure 2).
Figure 2 Installing the VRS to an ASTRO Mobile
If an external Siren/PA is to be used, the option xxxxAA must be ordered which replaces
the HKN6153A cable with a HKN6154A cable, or a separate HKN6154A cable must be
ordered. To install, plug the "T" side of the HKN6164A cable to the Siren/PA. Replace
the mounting screw on the HKN4363B cable with the double length screw. Plug this side
into the "T" cable. Plug the DB-25 end of the HKN6154A into the VRS (see Figure 3).
Figure 3 Installing the VRS with an External Siren/PA
Mobile Radio Operation and EME Exposure
To assure optimal radio performance and that human exposure to radio frequency
electromagnetic energy is within guidelines referenced earlier in this document, transmit
only when people outside the vehicle are at least the minimum lateral distance away from
a properly installed, externally-mounted antenna. Table ? lists the minimum lateral
distance for the VRS 750:
Rated Power of Vehicle-installed
Mobile Two-way Radio
Less than 7 Watts 8 Inches (20 Centimeters)
Minimum Lateral Distance from
Transmitting Antenna
VRS Antenna Installation
Recommended mobile antenna installations are limited to metal body vehicles at the
center of the roof and center of the trunk deck locations.
Install the antenna to be used with the VRS according to the instructions supplied with it
by the manufacturer (an antenna is not included with the VRS models). Mount the
antenna as far from the mobile radio antenna as possible, but never less than three feet.
An ideal configuration would be a roof-mounted mobile radio antenna and a trunkmounted VRS antenna. Connect the antenna cable mini-UHF connector to the antenna
jack on the rear of the VRS unit. A mini-UHF crimp connector is provided with each
VRS750 unit for easier installation with a pre-existing antenna.
VRS750 Programming
The user selectable operating parameters for the VRS750 reside in the ASTRO mobile
EEPROM during normal operation. The EEPROM located in the VRS750 holds the
tuning parameters. The VRS750 programming windows reside in ASTRO Spectra CPS
and are accessible when the “VRS-EP Option” is enabled in CPS under the Radio
Configuration->Radio Wide->Advanced window (see Figure 4).
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