Antenna Tuning or Cutting

Selecting and installing a proper antenna for a telemetry radio, GPS transponder, or base station involves selecting a suitable style of antenna for your installation, properly mounting the antenna, cabling the antenna to the radio connection, and possibly adding a lightning arrestor to the antenna cable.  One of the most important considerations is ensuring you select an antenna that works well for your operating frequency.  In many cases this involves tuning the antenna for the proper frequency.

Any antenna is constructed of a metal conducting element.  Often this element is insulated from direct contact with a rubber or fiberglass sheath, or some other material and you will not see the metal element itself.   In any good antenna the shape and length of the element was carefully considered when the antenna was designed.  Some elements are simple straight thin metal rods, others are coils, loops or other styles or combinations.  Frequently the antenna is built to work at a very specific frequency or range of frequencies, such as 450-460MHz.  If you select an antenna built for the wrong frequency you will have very poor results.

Some common antennas allow for the user to adjust the antenna for their frequency.  The antenna may be built to cover a wide range of frequencies, such as 400-500MHz, but should be adjusted to the precise user frequency.  As radio transmissions are actually radio “waves” you may remember that a radio frequency and radio wavelength are tightly related.  Tuning an antenna typically involves adjusting the length of the conducting element(s) to be a specific ratio of the actual radio wavelength.

Often field tunable antennas involve 2 elements that are allowed to slide or telescope back and forth to achieve a specific antenna length.  In other cases the element(s) may need to be physically cut or altered to a specific length.   In the case of a common omni-directional fiberglass antenna the metal element(s) are housed within a fiberglass insulative sheath, and must be removed from the sheath to gain access.  Here the user must expose the metal conductive element(s) and cut them to the proper length.  If the antenna has multiple elements , each element may require a different cut and re-assembly must place them in proper order.

To physically cut the element(s) a good metal file, Dremel tool, or fine tooth metal saw may be used to cut the element(s), or score and snap them carefully.  Once done the element(s) go back into the fiberglass sheath in correct order.  You can smooth any sharp points first if you like.

 If an antenna is meant to be tunable it will come with a chart or other instructions as to what length is intended for a specific frequency, and perhaps instructions on how to physically perform the cut or adjustment.  If  you intend to cut-to-tune your antenna remember these 5 key points:

• Never cut an antenna unless you are certain you need to do so.
• Make sure you have clear instructions on how to measure and cut the antenna for your frequency, and measure very carefully.
• If the antenna contains multiple elements, plan and track each element with individual care.
• Wear eye protection and follow any safety procedures.
• Never cut the element too short.  It may be better to take it increments at a time to achieve proper length.

If you order an antenna from us that requires cutting, we are happy to do this for you prior to shipping if you can tell us the precise frequency you need.

The RavTrack Atlas PL personal GPS locator radio network capabilities

Most people will identify the Atlas PL personal locator as an excellent device for people to wear and to send GPS position information, alerts, and man-down status.  Typically the Atlas PL is used in conjunction with the RavTrack AVL GPS vehicle transponders which are equipped in fleet vehicles and used for base receiving stations as well as store-and-forward repeaters.  It is common for these latter transponders to be used to complete a GPS tracking radio network for tracking both personnel, and vehicles, or other costly assets.

However, it is also possible for the Atlas PL units alone to be used to construct a GPS tracking network complete with multiple base stations and/or a repeater, without the involvement of the vehicle transponder models in the system.  The Atlas PL inherently has all the capabilities of the vehicle based models.  Releasing these capabilities is simply a matter of following correct configuration procedures for the Atlas PL.

The following diagram demonstrates the use of the Atlas PL in its traditional role as a personal GPS transponder but also as multiple base stations, with one base station also serving as a repeater.

Within each box are typical settings of the Atlas PL as part of the GPS tracking scheme.  Above each box are the intended uses of each Atlas PL in the tracking network, while below each box are a series of configuration commands the user should issue to each Atlas PL unit to configure each unit for the particular use specified.  Finally, alongside each command is an indication of what that command actually configures in the Atlas PL.

Each Atlas PL starts out in GPS mode 8.  This configures the Atlas PL to function in the most common transponder configuration and enables the advanced battery management functions of the Atlas PL as well.  However, it is important to note that the command GPS – such as GPS 8 – is a macro command which configures many different aspects of the unit.  Most commonly the GPS command is understood by the user to set the format of the NMEA output, but it in fact does much more.  For instance, issuing  the command “GPS 8” to an Atlas PL will completely turn off the receiver circuitry of the unit. This is not what we need for a base station receiver or repeater.  The subsequent commands change other configurable attributes of the Atlas PL, overriding the macro set of configuration parameters, to arrive at the final desired configuration.  It is critical these configuration commands be issued after the GPS command.

We hope this demonstrates some of the capabilities of the Atlas PL not commonly identified by the end user.  Should you have in mind a specific function of an Atlas PL that is not apparent, we encourage you to contact us.

Fast GPS reporting with TDMA timeslots

RavTrack is very fast at reporting the positions of even large fleets over a single radio channel because each RavTrack transponder is assigned a specific time slot in which to transmit, avoiding interference which may occur if multiple devices were permitted to transmit simultaneously. The fact that all transponders share a “common clock” via the GPS satellite signals allows us to assign a unique timeslot to each device, yet maintain timing coordination over a large fleet of devices.

RavTrack timeslots are built on 50 millisecond increments by factory default, athough 10msec granularity can be achieved with newer firmware versions. For the purposes of illustration we will assume each time slot must be a multiple of 50msec. The specific size of your time slot is typically determined by the bandwidth/transmission rate of your particular transponder and the presence or absence of a repeater.

Most FCC licenses granted in the USA are for narrowband (12.5KHz) channel spacing. The associated RavTrack transponders operate quite well at 4800 baud transmission rate (factory default), although slower rates can be used. These transponders can complete a position report transmission in about 64msec, so a 100msec timeslot would be the factory default when no repeater is in the system. If your license permits wideband (25KHz) channel spacing, and your transponders are capable of wideband operation, the factory default transmission rate is 9600 baud. In this instance a position transmission can be completed in about 32msec, so a 50msec timeslot is typically used when no repeater is in the system.

If your system uses a store-and-forward repeater you need to make each timeslot longer so that once a vehicle reports, the repeater has sufficient time to receive, process, and repeat the transmission on “quiet air” before the next vehicle transmission occurs. In a 9600 baud system a 100msec timeslot may be used if you are not encrypting your transmissions, but with encryption a 150msec time slot should be used, as the repeater needs a bit more time to process an encrypted message than an unencrypted message. In a 4800 baud system using a repeater a 200msec timeslot may be used whether or not you are encrypting the position transmissions.

Timeslots are numbered starting at zero, and the zero time slot is reserved by the system. Thus you can start numbering your transponder time slots at slot 1 (0001). In a system using 100msec timeslots the first second is completed once time slots 0 through 9 are used (10 time slots total). For this reason, up to 9 vehicle transmissions can be completed in the first second, and in this example your fleet size would be limited to a total of 9 vehicles if you need the entire fleet to report each second. As the reserved zero time slot only occurs at the start of any particular TDMA cycle, cycles longer than 1 second would allow the addition of 10 more time 100msec slots for each second added to the cycle. Thus a fleet using 100msec time slots can provide reports from 19 vehicles every 2 seconds, 29 vehicles every 3 seconds, and so forth. Similar logic applies to other RavTrack timing schemes.

If your fleet is quite large and you want faster updates than the 100msec timeslot scheme allows, you can double your fleet size if local regulations allow you to use wideband transmissions that yield a 50msec time slot.  In many deployemnets a fleet can scale much larger and still preserve fast report cycles simply by using multiple frequencies.  As transponders on different frequencies will not interfere with one another even if transmitting simultaneously, a properly architected system using five frequencies can report five times faster than the same system using only one frequency.

When setting up your fleet timing it is a good idea to leave a little extra capacity in your timing scheme to allow the easy addition of new vehicles to the fleet.

Finally, if you want to use the RavTrack transponders to transmit not only position data, but extra data as well (e.g. from an on-board telemetry device), you will need longer time slots to send this extra data. Please contact us in this regard, and we are happy to help you in architecting a solid system.

For a more technical programming perspective on TDMA time slots as used by RavTrack see the following articles: http://ravtrack.com/GPStracking/tdma-transmission-overview/361/  

http://ravtrack.com/GPStracking/tdma-time-slots/71/ 

or consult your technical manual.

The U.S. Department of Commerce requires that all exportable GPS products contain performance limitations so that they cannot be used in a manner that could threaten the security of the United States. The following limitations are implemented on the Trimble Copernicus receiver receiver.

Immediate access to satellite measurements and navigation results is disabled when the receiver’s velocity is computed to be greater than 1000 knots, or its altitude is computed to be above 18,000 meters. The receiver continuously resets until the COCOM situation is cleared.

If the Raveon GPS transponder will be used in aviation applications, the unit should be put into the AIR mode.  See the posting “gps-receiver-dynamics” for information about the AIR, LAND< and SEA modes.

The GPS receiver in Raveon’s M7 and Atlas PL GPS transponder may be configured for different situations. By default it is configured for LAND operation.
Selecting the correct operating parameters has a significant impact on GPS receiver performance.  GPS receiver dynamics may be optimized for LAND, AIR, or SEA operation.
  
  LAND  = 1    Maximum speed the GPS will receive at is 233knots/268mph/430kmh
  SEA = 2    Maximum speed the GPS will receive is not specified.
  AIR = 3   Maximum speed the GPS will receive at is 1000knots/1150mph/1800kmh
 
The default setting for the GPS receiver used in Raveon’s M7 series of GPS transponders and Atlas PL Transponders is LAND.
The default LAND operating parameters allow the receiver to perform well in most environments. Transponders with firmware version C12 or higher are able to view the GPS receiver’s configured dynamics, and change the dynamic mode between AIR, LAND, and SEA. Upon power up, the firmware reads the internal GPS receiver’s current configuration.

The user can optimize the internal GPS receiver in the transponder to a particular application.  If the receiver is then taken out of this environment, the specifically tuned receiver may not operate as well as a receiver with the default options.
The dynamics feature default setting is LAND mode, where the receiver assumes a moderate dynamic environment. In this case, the satellite search and re-acquisition routines are optimized for vehicle type environments. In SEA mode, the search and re-acquisition routines assume a low acceleration environment. In AIR mode, the search and reacquisition routines are optimized for high acceleration conditions. 

Reading the GPS Receiver Configuration

The GPS receiver configuration may be determined by using the GX command to show the overall configuration of the M7 or Atlas PL transponder. The “Dynamics” command will also return a string in the following format that indicates how the GPS receiver in the transponder is currently configured.   

MMM, EE.E, SS.S

 MMM: dynamic mode AIR, LAND, or SEA
 EE.E: Elevation Mask
 SS.S: Signal Mask  

Elevation Mask

This is the minimum elevation angle for satellites to be used in a solution output by the receiver. Satellites which are near the horizon are typically more difficult to track due to signal attenuation, and are also generally less accurate due to higher variability in the ionospheric and tropospheric corruption of the signal. When there are no obstructions, the receiver can generally track a satellite down to near the horizon. 

Signal Mask

This mask defines the minimum signal strength for a satellite used in a solution. There is some internal hysteresis on this threshold which allows brief excursions below the threshold if lock is maintained and the signal was previously above the mask.

Configuring the Dynamics

Use the DYNAMICS command to set or read the dynamics.  DYNAMICS with no parameter will return the configuration.  The following commands may be used to set the dynamics:

DYNAMICS 0    (factory default dynamic mode)
DYNAMICS 1    (LAND)
DYNAMICS 2    (SEA)
DYNAMICS 3    (AIR)

When issuing the DYNAMICS x command, give the GPS receiver a few seconds to execute it.  The M7’s firmware will also send a “flash save” command to the GPS receiver after the dynamics configuration is changed so that the change becomes permanent in the GPS receiver.  Upon power-up, the GPS receiver will use the new dyncamics setting. 

To verify the dynamics setting was saved, cycle power on the M7 or Atlas PL, enter the CONFIG mode, and enter the GX command to view the overall configuration of the device. The GPS receiver dynamics will be displayed.

Advanced GPS Receiver Configuration

To facilitate the advanced user, Raveon added a command “PASS” in the C12 firmware.  PASS will pass the parameter of the command to the internal GPS receiver in NMEA format. The GPS receiver used in the M7 transponder and ATLAS PL personal locator is a Trimble Copernicus II.  The technical manual for the Copernicus II contains details on how to configure it using NMEA type messages.  

For example, to set the GPS receiver to AIR mode, issue the following command while in the command mode.
    PASS $PTNLSCR,0.60,5.00,12.00,6.00,0.0000020,0,3,1

The command’s paramter is a NMEA formatted sentence without the * or the checksum.  The M7 or Atlas will append the * and the checksum to the sentence before sending it to the internal GPS receiver.  To set the dynamics, use the DYNAMICS x command, not the PASS command. The PASS command is provided to the advanced user who wished to reconfigure the receiver’s low-level configiruation paramters such as signal and elevation masks. 

If you change the GPS receiver’s configuration with the PASS command, do not forget to issue the save configuration command to the GPS reciever. The save command for the GPS receiver in the M7 and ATLAS PL is:
 PASS  $PTNLSRT,H,2,7,0

Overview

The M7 GX series of GPS transponders may be directly connected to a Garmin Oregon 450. When connected, the Garmin display map will show the location of the vehicle it is in PLUS the location of all other M7 transponders within radio range.  This unique feature allows one to quickly, easily, and inexpensively, make a mobile AVL system for tracking cars, trucks, race cars, construction equipment, or any thing Raveon’s M7 GX transponder may be installed on.

The Garmin Oregon 450 has a built-in interfaces for a “NMEA 0183? devices, which is another way of saying that they can connect to other devices using a serial cable.   The NMEA 0183 is an RS232 serial connection that typically operates at 4800 baud.  It is used to exchange way point and other information between displays, GPS devices, and transponders.

When Raveon’s M7 GX transponder is connected to the Oregon using the NMEA 0183 connection, the M7 transponder can put icons on the screen of the Garmin display.  As the transponder received updated positions from other vehicles, it updates the position of the icons on the Garmin display.

How NMEA 0183 works

Here is how their NMEA 0183 interface works:

NMEA 0183 Cable Connections

NMEA 0183 is a standard communications format for marine electronic equipment. For example, an autopilot can connect to the NMEA interface of a GPS and receive positioning information.  The GPS can exchange information with any device that transmits or receives NMEA 0183 data. See the following diagram for general wiring connections. Read your product’s owner’s manual for specific wiring information.

NMEA 0183 Wiring  (Data cable)

The Garmin Oregon 450 uses the yellow wire to transmit, the white wire to receive and the Black and green wire for ground.

The M7 DB9 Serial Connector

The 9-pin serial I/O connector on the M7 is a female 9-p D-sub miniature connector having the following pins configuration.

Front-view of DB-9 connector on modem (female)

Wiring the DB9

The Oregon’s “Data Cable” must be connected to the M7 transponder.  This connection will allow the M7 to put icons on the screen of the Oregon display, showing the location of other tracked vehicles.  The Raveon M7 GPS transponder uses a 9-pin “DB9? connector to connect to the Oregon.  Solder the Oregon data cable wires onto a DB9 connector and plug the DB9 into the M7 transponder as shown below:

The white wire goes to pin two of the DB9, the yellow wire to pin 3, the black and green wires get twisted together and both go to pin 5, and the red wire goes to pin 9 of the DB9. It is recommended that you keep the fuse on the red wire when setting up the DB9 connector.

Configuring the M7 GX Transponder

Raveon has a designed the M7 GX transponder to work with Garmin Oregon Display or any other NMEA 0183 display that can accept the “$GPWPL” NMEA message.   The $GPWPL is an industry standard message that the Garmin displays and many other GPS displays interpret as a way point command.  The M7 GX outputs this $GPWPL message to put icons on the screen of the Garmin, and to move the icons around on its screen.

To configure the M7 transponder to output the $GPWPL message, set the M7 GX to GPS mode 2.  To do this, put it into the configuration mode by send the +++ into the serial port.  The M7 will respond with an OK.  Type GPS 4 and press enter to put it into GPS 4 mode.  GPS 4 is the mode that causes the M7 GX to output $GPWPL messages whenever it receives a status/position message over the air.

Raveon Technologies Corporation

990 Park Center Drive, C

Vista, CA 92081

sales@raveontech.com

760-727-8004

It is usually possible to upgrade the RavTrack PC AVL software program to a newer version without re-installing the software as long as the major revision number is the same.  (2.6 to 2.7, 3.1 to 3.3 …)  Most upgrades can be performed by simply replacing the RavTrackPC.exe file which is stored in the program directory on your computer. This quick upgrade method avoids having to perform a full re-install of the RavTrack PC AVL software when simply upgrading to the current version.

To perform the quick update:

1. Close RavTrack PC.    File > Exit
2. Click on the link below to download a copy of the latest .exe file:
   http://ravtrack.com/downloads/RavTrackPCexe.zip or use the .exe file emailed to you from Raveon tech support.
3. Open the .zip archive folder by double-clicking on it. 
4. Locate the directory on your computer that holds the RavTrack PC program. For most users the full path to this file is:  C:/programfiles/raveon/RavTrack PC/
5. Rename the current RavTrack PC.exe file file to RavTrack PCold.exe.
6. Copy the new file from the  named RavTrack PC.exe to your RavTrack PC program directory. For most users the full path to this file is:  C:/programfiles/raveon/RavTrack PC/RavTrack PC.exe

You may now run RavTrack PC as you have been, and the new version will be executed.  If there are data base upgrades to do, RavTrack PC will automatically perform the updates when it starts up.

The M7 GX series of GPS transponders may be directly connected to a Garmin 60C series of hand-held GPSs.  All members of the Garmin 60C family have an RS232 option that is compatible with NMEA 0183 messages.  This allows them to be used with Raveon’s RavTrack series of GPS radio transponders to make a complete GPS tracking system.

When connected to the M7 GPS radio transponder or the Atlas PLPersonal Locator, the Garmin’s map will show the location of all of the the user PLUS the location of all other transponders within radio range.  This unique feature allows one to quickly, easily, and inexpensively, make a portable AVL system for tracking cars, trucks, racecars, construction equipment, or any thing Raveon’s M7 GX or Atlas PL transponder may be installed on.

The Garmin 60C series of hand-held GPSs have built-in interfaces for a “NMEA 0183″ devices, which is another way of saying that they can connect to other devices using a serial cable.   The NMEA 0183 is an RS232 serial connection that typically operates at 4800 baud.  It is used to exchange way-point and other information between displays, GPS devices, and transponders.

When Raveon’s M7 GX transponder is connected to the Garmin display using the NMEA 0183 connection, the GPS radio transponder can put icons on the screen of the Garmin display.  As the transponder receives updated positions from other vehicles, it updates the position of the tracked vehicle icons on the Garmin’s display.

Garmin 60C, 60CS, 60Cx Wiring

From the Garmin technical manual, here is how their NMEA 0183 interface works:

NMEA 0183 Cable Connections

NMEA 0183 is a standard communications format for marine electronic equipment. For example, an autopilot can connect to the NMEA interface on the Garmin 60C and receive positioning information.  The Garmin 60C series can exchange information with any device that transmits or receives NMEA 0183 data.  See the following diagram for general wiring connections. Read yourother product’s owner’s manual for more wiring information.

NMEA 0183 Wiring  (Data cable)

Wiring the Serial Cable

The Garmin’s “Data Cable” must be connected to the M7 GPS transponder (or Atlas OL).  This connection will allow the M7 to put icons on the screen of the Garmin display, showing the location of other tracked vehicles.  The Raveon M7 GPS transponder uses a 9-pin “DB9″ connector to connect to the Garmin.  Solder the Garmin data cable wires onto a DB9 connector and plug the DB9 into the M7 transponder as shown below:

Connect the white wire(serial data from M7 into Garmin) from the Garmin’s Serial Cable goes to pin 2 of the M7’s RS232 DB9 connector.  You do not need to connect the brown wire(serial data from Garmin), so you can trim it off.  Connect the shield braid of the Garmin Serial Cable to pin 5 of the DB9.  The red wire optionally can connect to pin 9 of the Raveon GPS transponder’s DB9 to power the Garmin from the DC source that powers the M7.

If you do not wire your own cable, but instead use Garmin’s RS232 serial cable, you will need to connect the Garmin’s RS232 cable to the M7 GPS transponder using a “NULL Modem” adaptor.

Configuring the Garmin

Set the NMEA communication of the Garmin to 4800 baud.

Configuring the M7 GX Transponder

Raveon has a designed the M7 GX transponder to work with Lowrance Display or any other NMEA 0183 display that can accept the “$GPWPL” NMEA message.   The $GPWPL is an industry standard message that the Lowrance displays and many other GPS displays interpret as a waypoint command.  The M7 GX outputs this $GPWPL message to put icons on the screen of the Lowarance, and to move the icons around on its screen.

To configure the M7 transponder to output the $GPWPL message, set the M7 GX to GPS mode 2.  To do this, put it into the configuration mode by send the +++ into the serial port.  The M7 will respond with an OK.  Type GPS 4 and press enter to put it into GPS 4 mode.  GPS 4 is the mode that causes the M7 GX to output $GPWPL messages whenever it receives a status/position message over the air.

Overview

Many different types of batteries may be used with Raveon’s M7 series of GPS transponders.  This Technical Brief describes how well some common battery types will work with the M7 radios.

Actual battery life will vary based upon how often the M7 GPS transponder transmits, but the data in this Technical Brief may be used to predict the battery life of most configurations.

Test Setup

For the tests in this brief, a UHF GPS transponder, model RV-M7-UC-GX was configured in GPS mode 2 to transmit its position every 10 seconds.  In GPS mode 2, the radio’s receiver is on 100% of the time, and the current draw of the M7 was an average of 90mA.  The peak current draw was 2.1 amps for 68mS each time the M7 transmitted its GPS position.

Summary Data

Duracell Alkaline

These batteries are the common Duracel batteries found at most department stores.

Test Result Summary

Initial Voltage:                                   12.57 volts

Voltage at ½ discharge:                   10.2 volts

Usable life (hours)                           18 hours

Voltage drop when transmitting       2.4V  (1.1 ohm resistance)

Approximate mAh capacity             1600mAh

Discharge Curve

Transmit Transient

The plot below shows the dip in voltage as the transmitter turns on and off.

Summary

The Duracell is an OK battery to power the M7 transponder.  But its high internal resistance will reduce the RF power output after the first few hours of operation.  The DC to the radio should stay above 9V while transmitting for full power, above 8V for 3-4 watts.

Energizer Lithium

These batteries are the common Energizer Lithium batteries for cameras and digital electronics found at many department stores.

Test Result Summary

Initial Voltage:                                      12.1 volts  (14V for a few moments)

Voltage at ½ discharge:                      12.0 volts

Usable life (hours)                              28 hours

Voltage drop when transmitting          3.5V  (1.6 ohm resistance)

Approximate mAh capacity                2520mAh

Discharge Curve

Transmit Transient

The plot below shows the dip in voltage as the transmitter turns on and off.

Summary

Even though the internal resistance of the cell is higher than the alkaline, the Energizer Lithium is a good battery to power the M7 transponder.  Its high internal resistance will not reduce the RF power output because its voltage is fundamentally fairly high.  The DC to the radio should stay above 9V while transmitting for full power, above 8V for 3-4 watts, so the 3.5V dip means the radio will have full power at 12.5V, and 3-4 watts out at 11V DC at the battery pack.

Lenmar R2G NiMH pack, 2150mAh cells

These batteries are Nickel Metal Hydride rechargeable batteries.  They were fully charged before the test.

Test Result Summary

Initial Voltage:                                      11.0 volts

Voltage at ½ discharge:                      10.3volts

Usable life (hours)                              17 hours

Voltage drop when transmitting          2.0V  (.95 ohm resistance)

Approximate mAh capacity                1500mAh

Discharge Curve

Summary

These batteries should be a good power source for the M7 GX transponder.

The internal cell resistance is low, but the voltage is also low. The RF power output stayed at full power for most of the life of the battery, dropping to about 4 watts at the end of the battery life.  The double dip at end of live was due to the fact the radio keep working down to 6 volts (albeit with almost no RF output because the RF PA is off), and the batteries keep putting our very low voltage for another couple hours.

Raveon Technologies Corporation

990 Park Center Drive, C

Vista, CA 92081

sales@raveontech.com

760-727-8004

Integrated into RavTrack PC GPS Tracking software is a powerful report generating software program called Crystal Reports.

As part of the RavTrack PC installation, a run-time redistribution module is installed on the computer along with RavTrack PC. The Crystal Reports run-time module allows crystal reports to be generated by RavTrack PC, and viewed by the user.  But, it does not include the report editor.  To customize your own Crystal Reports, you will need to by a full-version of Crystal Reports 10.   The run-time module included with RavTrack PC will give you the ability to view the Crystal Reports you generate with RavTrack PC’s report generator.

Installation Problems

There is often an installation error with the Crystal Reports run-time on certain Windows Vista machines.   If during the installation of RavTrack PC you get an error message about Crystal Reports, you can ignore it because there is a simple solution that can be performed after the installation of RavTrack PC is complete.

If, after RavTrack PC is installed and operating, you get an error when trying to open the report generator in RavTrack PC  (View > Reports), then you should manually install the Crystal Reports 10 run-time module.  To do this, perform the following steps:

1. Close RavTrack PC.
2. Download the Crystal Report run-time module from Raveons server at: http://ravtrack.com/downloads/CRBasicVS2008_redist_x86.zip
3. Unzip the file to your local disk.
4. Open Explorer, and go to the directory where the .zip file was stored to.
5. Double click on the  CRRedist2008_x86.msi file to run the installation program.
6. Follow the instructions in the installer, and let it install.
7. Once the Crystal Reports installer has finished, start RavTrack PC, and verify the report features are working.

With release of RavTrack PC vesion 3.1, RavTrack PC supports Microsoft’s SQL Server 2005 and 2008.  By default, RavTrack PC uses Microsoft Access databases and tables to store its inforamtion.  Access is a very good choice for a database when RavTrack PC software is ging to be run on a single workstation, in a vehicle, or when the number of concurrent users is small. 

But, when the number of users running RavTrack PC increases, or when the size of the Log table is large, Microsoft’s SQL Server is a superior product, albeit a bit more complex to install and manage. 

You can download RavTrack PC evaluation copy free as well as the technical manual from Ravoen’s web site at: http://ravtrack.com/RavTrack-PC-Software.html 

If you are going to use a Microsoft SQL Server 2005 or SQL Server 2008 database with RavTrack PC, then you will need to prepare the SQL Server first, before running RavTrack PC.  Perform the following steps:

SQL Server Installation

1. Install Microsoft SQL Server or SQL Server Express.  SQL Server Express is available from Microsoft at no charge. It may be downloaded at: http://www.microsoft.com/Sqlserver/2005/en/us/express.aspx
2. Use the “SQL Server Configuration Manager” software program that is installed with MS SQL Server to configure the server.
3. Using the SQL Server Configuration Manager, enable the TCP/IP Client Protocol (SQL Server Configuration Manager > SQL Natice Client Configuration > Client Protocols > TCP/IP).
4. Also download and install the “Management Studio” for SQL Server.  The Express version may be downloaded at the same website as the SQL Server Express is downloaded from.
5. Set the default transaction time-out of Management Studio to 1000 seconds (Tools> Options> Designers> Transaction Timeout)
6. Using the Management studio, create a database with the name “RavTrack”. You do not need to create any tables in the database, as RavTrack PC will create them the first time it connects to this database.
7. Using Management Studio, create Login accouts for all users what will be accessing the SQL database using RavTrack PC. 

Troubleshooting:

If you are having trouble connecting RavTrack PC to your SQL server installation, check the following items:

1. Shut down RavTrack PC using FIle > Exit, and restart it.  Whenever the database type is changed in RavTrack PC, you should restart the application.
2. Install Microsoft’s Management Studio applicationon the computer running RavTrack PC.  Use Management Studio to connect to the server to verify that the SQL Server is running properly and accessible from the workstation.
3. Make sure the the TCP/IP Client Protocol is enabled on the SQL Server.
4. Make sure you are logged into RavTrack PC as an administrator with the ADMIN account.
5. Make sure you have purchased and installed an “Unlimited” license on RavTrack PC. The “Limited” version will not connect to an SQL Server.
6. Make sure you created a database on the SQL server named “RavTrack”.  The RavTrack database needs to be on the server before running the RavTrack PC program.  Yse the Management Studio to create the “RavTrack” database on the server.
7. You should have an account on the SQL Server computer with the same name and password as the name/password that you used to log onto Windows on the RavTrack PC computer. If you have not done this, create a Windows user account and password on the SQL Server computer to match the Windows user/password on the RavTrack PC Windows login account.
8. Make sure the rights assigned to the login account are at least db_reader, db_writer, and db_admin. 

RavTrack PC receives $PRAVE messages from a Raveon GPS tracking transponder, and uses the information in the $PRAVE message to plot the position and display the status of tracked vehicles and personnel.

The $PRAVE messages come out of the M7 GX transponder, when it is configured in GPS mode 2.  The serial port of the M7 GX transponder must be connected to the PC running RavTrack PC.   This connection may be a direct RS232 connection, or it may use a terminal server to convert the RS232 from the M7 GX transponder to Ethernet. The Ethernet connection is then made to a LAN or WAN so that RavTrack PC can receive the GPS positions via the nework connection.

To verify that RavTrack PC is receiving $PRAVE messages, you can look at the communications statistics window within RavTrack PC, and see if $PRAVE messages are comming out.

In the “Messages In” column, there are two numbers (xxx/yyy)  The first number xxx is the total number of messages, and the second number, yyy, is the total number of $PRAVE messages that RavTrack PC has received.

If the communications with the M7 GX transponder is OK, the second number will increment each time a $PRAVE message is received, which is each time a transponder reports in. In the above example, RavTrack PC has received 311 position reports using its network connection.

If the second number is 0, but the first number is not zero (ie  123/0)  then the connection to the M7 GX is probably OK, because some messages are coming in.  These are usually the $GPGGA/RMC type messages output from the local GPS in the M7.  They are not over-the-air position reports.  Because the first number is incrementing, the connection to the M7 is OK. But, because the second number is 0, there are not $PRAVE messages coming in.  The most likely reasons that there are not $PRAVE messages are:

1.  All transponders are turned off.

2.  The UHF or VHF antenna to the M7 GX used with RavTrack PC is not connected.

3. The encryption keyphrase is not set corectly, and the My GX cannot receive the position reports.

4. All transponders are out of range of the M7 GX used with RavTrack PC.

5. The transponders are configured on a different RF frequency.

Hopefully you find this information helpfull.  Monitoring the communication statistics is an excellent way to verify the performance of your RavTrack GPS tracking system.  RavTrac PC automatically monitors the statistics, and will turn the communication status button on the bottom of the screen red if no messages are received for a long period of time, indicating that the communications with the transponder used to receive $PRAVE messages has failed.

Microsoft SQL Server may be used as the database engine for the RavTrack PC AVL system.

A free version is available from Microsoft, called “Express”.  For small AVL systems where the number of tracked vehicles is small (< 25) and the update rate is fairly slow (< 30 seconds), then the EXPRESS version is probably a good choice. But, for systems requiring higher performance, Microsoft provides a number of high-performance options.

The following table describes the primary differences between the various SQL implementations.

Scalability and Performance

Feature	Express	Workgroup	Standard	Enterprise	Comments
Number of CPUs	1	2	4	Max OS supported	Includes support for multicore processors.
RAM Used	1 gig(GB)	3 GB	OS maximum	OS maximum	Memory limited by operating system.
64-bit Support	Windows on Windows (WOW)	WOW
Database Size	4 GB	No Limit	No Limit	No Limit
Partitioning					Support for large-scale databases
Parallel Index Operations					Parallel processing of indexing operations
Indexed Views					Indexed view creation is supported in all editions.

The RavTrack system offers very good coverage in many environments with a single base station and single antenna.  However, in some circumstances this is not sufficient to cover the entire tracked area, or other factors may move you to install multiple antenna locations.

First, before you decide that one receiving antenna is insufficient, take a look at your area.  Do you have a voice UHF system of about 5 watts?  The Ravtrack system coverage is typically similar to the voice system coverage, although not necessarily identical.

Consider if you can mounting the base station antenna as high as possible to cover the desired territory.  In some cases this may mean moving the antenna away from the control room to achieve the best coverage.  A skilled RF technician familiar with your area can probably determine a good antenna location, sometimes by performing a site survey, or simply by experience.

Because you want to keep the antenna cable that links the antenna to the receiving modem as short a possible, this may mean that the receiving modem is moved from the vicinity of the tracking PC.  RS232 serial communication links have strict distance limitations.  However, if you have (or can get) Ethernet/IP communications between the base modem and the computer you can use a “terminal server” (AKA telnet server, serial-IP convertor) to place the base modem onto the Ethernet/IP backbone.  From here the position updates are carried via network telnet services from the base modem to the PC.

This approach can also be used to spread mulitple receiving base stations around your area, to improve coverage.  Again, you need an Ethernet/IP backbone linking all the antenna sites to your tracking PC.  You may check with your I.T. department if you have one, for help.  The Ethernet/IP backbone may be wired or wireless.  A number of wireless solutions exist. 

If you use this approach make sure your tracking software can acquire the telnet stream (sometimes you may use another telnet server), and/or that it can acquire multiple base station modems.  RavTrack PC currently supports up to 6 base station modems.

For much more detail on using terminal servers see application note 140 “Using an Terminal Server to expand your Ccverage area” at the following link.

http://ravtrack.com/pdf_appnotes/AN140(RavTrackTermServ).pdf

If for whatever reason this approach is impractical, one or more repeaters may be in order.  Remember that with RavTrack you don’t need to order fancy equipment to provide the repeater.  Any RavTrack transponder can easily be programmed to serve as a store-and-forward repeater.  Just ensure you make good locati0n and antenna choices.  For more information on antennas see the following tech blog “Antennas for a RavTrack vehicle tracking system”:

http://ravtrack.com/GPStracking/2009/antennas-for-a-ravtrack-vehicle-tracking-system/

One of the  advantages of using a repeater in your system is that the repeater will “repeat” any vehicle transmission it receives back out over its entire area of coverage.  Remember your vehicle transponder not only sends its own position information, but can receive the same from other fleet members, a feature fairly unique to RavTrack.  So, if you are equipping vehicles with tracking displays to do just that, those vehicles will not only receive position reports from other nearby fleet members, but those that are further away as well when using a well positioned repeater. 

On the flipside, a store-and-forward repeater does just that, it first receives and stores a transmission, then repeats out that same transmission.  While the RavTrack transponder has an extremely quick turn-around time from receiving to transmitting, it still will take time to receive then repeat.  Because of this the total duration of a transmission may need to be extended by lengthening the duration of each transmission slot in the system, and  you may want to recalculate system timing parameters and overall system performance and scalability projections.  If you have multiple repeaters they may require  further time slot expansions.  This is the prevalent case if you deploy each repeater using the same repeat frequency.  For more information on system timing with and without repeaters please refer to the techblog  “TDMA Time Slots”: 

http://ravtrack.com/GPStracking/2009/tdma-time-slots/

If your scenario will require you to install multiple repeaters, there are different methods for doing this as well, and different tradeoffs in the process. 

Whatever issues you face we encourage you to contact us so we can help you work towards the best approach for your particular system.

In a RavTrack system you will need antennas for vehicles, as well as base stations, and possibly repeaters if your particular system uses any repeaters.   Here will will discuss common antennas for all three uses.

The Raveon “GX” series of tracking transponders used in a RavTrack system can be configured to operate as a vehicle unit, a base station, or a repeater, all by software configuration.  Each GX transponder will have 2 antenna connections.  One is for a GPS antenna, and the other for a UHF antenna.

Here is a picture of the GX transponder in the standard enclosure.  Note that the GPS antenna connector is an SMA female, while the UHF connector is a BNC female.  They are at opposite ends of the transponder.

Note that if your transponder is the weatherproof version  the UHF connector is TNC female.  Transponders installed in vehicles for tracking purposes will require both a GPS antenna and a UHF antenna. We have a few antennas that are combination GPS and UHF antennas.  When these are offered the antenna cable(s) will terminate in 2 separate connections.

The GPS antenna receives the GPS satellite transmissions by which the transponder will determine its precise GPS location.  Note that the location is actually that of the antenna itself, which may be important to remember especially when dealing with large vehicles or other objects.

Once the location is determined the UHF antenna is required to allow transmission of the vehicle location.  The UHF antenna should be a “mobile” antenna chosen to match the proper transmission frequency of your system, as well as selected to best suit the type of vehicle.  The UHF antenna is almost always larger than the GPS antenna so size and styling can be important criteria.

Anther important criterion is the manner in which the antennas mount to the vehicle.    It is best to have the antennas as high up on the vehicles as practical, and generally speaking larger (UHF) antennas are typically better performers.  However an overly large antenna may not just be unsightly but prone to damage as well.  Some vehicles will be equipped with an “antenna bar” in order to mount the antennas.  As multiple antennas may posssibly compete with one another, it is best if a skilled RF technician is consulted or contracted to perform the installation.

Antenna mounts come in a variety of approaches of which the 3 most common are magnetic mount, through-hole mount, and flange mount.  The magnetic mount is most suitable for temporary installations, although the magnets are quite strong and the antennas may stay put even under challenging circumstances.  The through-hole mount is the sturdiest and most permanent, but requires a hole be drilled through the vehicle surface (or antenna bar).  The flange mount approach is typically used to grip the vehicle trunk lid, if this is available.  All of these mounts are available in “NMO” style where the UHF antenna physically threads on to the mount itself.  Here are some quick photos:

NMO style magnetic mount

Antenna threading onto NMO flange  mount.

Thorough-hole mount.

For more information on NMO mounts see the post “The versatile NMO antenna mount” in this section at:

http://ravtrack.com/GPStracking/2009/the-versatile-nmo-antenna-mount/

Oftten the GPS and/or UHF antenna will have a magnetic mount base or through-hole mount base incorporated as the antenna base.  Here is a photo of a combo GPS/UHF antenna with a through-hole base:

In some vehicle deployments the UHF antenna will not only broadcast location but will also receive transponder broadcasts from other fleet members.  This ability is fairly unigue to Ravtrack.

Once a location broadcast hits the air it is ready to be received by other fleet members but also by a base station or possibly a repeater.  Sometimes the base station is mounted on a mobile command vehicle, and special antenna considerations are in order.   However, typically the base station antenna is on top of a building, or an antenna tower.  Usually an omni-directional (all direction) antenna is used, as the vehicles can be broadcasting from many different locations.

The most common omni-directional base station antenna is made with a fiberglass sheath.  Here is a picture:

This sort of antenna typically mounts onto a pole or mast the customer provides.  Check to see if the actual mounting hardware is included with the antenna.

This antenna is also very effective for repeaters.  Sometimes, if a repeater is used the base station will use a directional antenna pointed at the repeater antenna.  Here is a picture of a Yagi style directional antenna used for this purpose:

Antennas can act as lightning attractors, so you may want to investigate lightning arrestors for some installations.

Here are some general rules if thumb when dealing with antenna installations::

Survey your area for best antenna locations

Use the largest antenna you can tolerate and afford

Make certain the antenna will work in your frequency

Determine your mounting and support early

Mount the antenna as high as practical

Try to keep the antenna cable short, and use good grade cabling

Take precautions against lightning and surge

Don’t forget signal cable and power for your transponders

Hire a skilled RF technician if at all possible

A popular type of antenna mount is called an “NMO” which stand for new Motorola.  NMO mounts come in a variety of types and are frequently used especially when installing mobile antennas.  Whether you are installing an antenna on a vehicle or a fixed structure the NMO mount may be a good solution.

The idea of the NMO mount is simple.  NMO mounts are devised to have a standard threaded connector where you screw on the antenna of choice to the mount of choice.  The NMO mount itself connects to the antenna and provides the antenna cable as well.  There are a large number of antennas that are built to screw on to the NMO mount. Simply look for an antenna with an NMO base.  Here is a simple picture of a mobile antenna with an NMO base combining to an NMO mount:

  Here an antenna with an NMO base will thread on to the NMO mount.  Note the antenna cable comes from the mount itself.

The NMO mount in the above example is a “trunk lid” mount.  The flange to the left hooks under the lid of a vehicle trunk.

Another popular type of NMO mount is the magnetic mount.  When affixed to many metallic surfaces the mount stays put quite well.  Here is a picture:

A third popular type  of mount is the through-hole mount.  This  requires a small (typically 3/8″ to 3/4″ ) hole be drilled through the surface hosting the mount, and is the best choice for an extremely rugged installation.  The “NMO” part of the mount protrudes above the mounting surface, becoming accessible to the antenna itself.  Here is a picture of a through-hole NMO mount:

The following external post provides a good look at a through-hole NMO mount assembly and brief description of the approach

http://www.radioreference.com/forums/radio-equipment-installation-forum/97536-install-nmo-antenna.html

The installation of a through-hole NMO mount and antenna is covered by this external video.  The video was shot by a fellow holding the camera in one hand while trying to perform the installation, so it is a bit shaky, but all-in-all he does an excellent job:

http://www.youtube.com/watch?v=zs-0EF7mP8k

Raveon can provide several NMO mounts and antenna types.  We invite your further questions.

The M7 transceiver has a 5-watt RF power output rating.  In a typical application the units is in Standby or Receive mode most of the time.  A small fraction of the time, it is transmitting.  But when it transmits, the M7 begins heating up, dissapating about 8 watts of heat.   This depends upon the RF power output setting and the DC input voltage. 

The temperature of the M7 enclusure must be kept below 60 degrees celcius, (140 farenheit) for proper operation of the unit.  For GPS transponder operation, there is no problem doing this, because the duty cycle is low.  But, if the M7 is used to send data, and is on the air a lare percentage of the time, then the enclusure’s temperature will begin to rise.  The following chart shows the case temperature at 25% and 50% Duty cycle. 

 

M7 Duty Cycle

You can see in the chart, that the M7’s enclosure temperature gets hotter if the DC input voltage is higher, or if the duty cycle is higher.  

For example, if the DC input voltage is 10V, and the unit is operated at 25% transmit duty cycle, then the enclosure temperature would be about 42 degrees C.  Given the same duty cycle, the enclosure temperature would be 46 degrees if the DC input were to be 14 volts. 

Raveon offers a heatsink option for the M7.  The heatsink is large finned heatsink that covers the top of the M7, and is secured on with thermally-conductive epoxy.  When this heatsink is attached, the M7 will stay cooler.  The following chart illustrates this:

The above data is the M7’s enslosure temperature with a heatsink secured to it.  The heatsink covers the top of the enclosure and uses normal air convection (no fan).  It reduces the case temperature by about 4-8 degrees.  

If a CPU cooling fan or similar fan were added instead, the case temperature rise would be only a few degrees above ambient.

The M7 GX series of GPS transponders may be directly connected to a Lowrance Globalmap 540C or a Globalmap 840C navigation display. When connected, the Lowrance display map will show the location of the vehicle it is in PLUS the location of all other M7 transponders within radio range.  This unique feature allows one to quickly, easily, and inexpensively, make a mobile AVL system for tracking cars, trucks, racecars, construction equipment, or any thing Raveon’s M7 GX transponder may be installed on.

Both the 540C and 840C have built-in interfaces for a “NMEA 0183″ devices, which is another way of saying that they can connect to other devices using a serial cable.   The NMEA 0183 is an RS232 serial connection that typically operates at 4800 baud.  It is used to exchange waypoint and other information between displays, GPS devices, and transponders.

When Raveon’s M7 GX transponder is connected to the Lowarnce diplay using the NMEA 0183 connection, the M7 transponder can put icons on the screen of the Lowrance display.  As the transponder received updated positions from other vehicles, it updates the position of the icons on the Lowrance display.

Lowrance 540C and 840C Wiring

From the Lowranace technical manual, here is how their NMEA 0183 interface works:

NMEA 0183 Cable Connections

NMEA 0183 is a standard communications format for marine electronic equipment. For example, an autopilot can connect to the NMEA interface on the GlobalMap 540c and receive positioning information.  The GlobalMap 540c can exchange information with any device that transmits or receives NMEA 0183 data. See the following diagram for general wiring connections. Read yourother product’s owner’s manual for more wiring information.

NMEA 0183 Wiring  (Data cable)

To exchange NMEA 0183 data, the GlobalMap 540c has one NMEA 0183 version 2.0 communication port. Com port one (Com-1) can be used to receive NMEA format GPS data. The com port can also transmit NMEA format GPS data to another device.  The four wires for the com port are combined with the Power Supply cable and NMEA 2000 Power cable to form the power/data cable (shown earlier). Com-1 uses the yellow wire to transmit, the orange wire to receive and the shield wire for signal ground. Your unit does not use the blue wire.

Wiring the DB9

The Lowrance’s “Data Cable” must be connected to the M7 transponder.  This connection will allow the M7 to put icons on the screen of the Lowrance display, showing the location of other tracked vehicles.  The Raveon M7 GPS transponder uses a 9-pin “DB9″ connector to connect to the Lowrance.  Solder the Lowrance data cable wires onto a DB9 connector and plug the DB9 into the M7 transponder as shown below:

The orange wire goes to pin two of the DB9, the yellow wire to pin 3, and the shield braid of he cable connects to pin 5 of the DB9.  The blue wire is trimmed off.

The extra wires on the Lowrance display called NMEA 2000 power are typically not used in a vehicle installation, and may be wrapped up with electrical tape and tucked away.

Configuring the Lowrance

Set the NMEA communication of the Lowrance to 4800 baud.

Configuring the M7 GX Transponder

Raveon has a designed the M7 GX transponder to work with Lowrance Display or any other NMEA 0183 display that can accept the “$GPWPL” NMEA message.   The $GPWPL is an industry standard message that the Lowrance displays and many other GPS displays interpret as a waypoint command.  The M7 GX outputs this $GPWPL message to put icons on the screen of the Lowarance, and to move the icons around on its screen.

To configure the M7 transponder to output the $GPWPL message, set the M7 GX to GPS mode 2.  To do this, put it into the configuration mode by send the +++ into the serial port.  The M7 will respond with an OK.  Type GPS 4 and press enter to put it into GPS 4 mode.  GPS 4 is the mode that causes the M7 GX to output $GPWPL messages whenever it receives a status/position message over the air.

It is possible to upgrade RavTrack PC from version 2.3 – 2.6 to version 2.7 by simply replacing the RavTrackPC.exe file in the program directory on your computer. This avoids having to perform a full re-install of the RavTrack PC software when simply upgrading to the current version.
Click on the link below to download a copy of the latest .exe file:
http://ravtrack.com/downloads/RavTrackPCexe.zip

Once you download it to your computer, open the .zip folder by double-clicking on it.  Copy the RavTrack.exe file your RavTrack PC program directory. For most users the full path to this file is: