RV-M7 Data Radio Modem Technical Manual

• General Information and Overview
• Specifications
• Electrical Inputs and Outputs
• Serial Port Commands
• Using the M7 Modem – Packet Mode
• Using the M7 Modem – Streaming Mode
• Installation
• FCC Licensing Information
• M7 Diagnostic Provisions
• Tuneup and Alignment
• Skyline Compatibility
• Antenna Information
• Appendix A.   Serial Port Hardware
• Troubleshooting
• Mechanical Information

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RV-M7 Data Radio Modem Technical Manual

FCC Licensing Information

M7 radio modems operate on radio frequencies that are regulated by the Federal Communications Commission (FCC). In order to transmit on these frequencies, you are required to have a license issued by the FCC.

Almost everyone engaged in public safety activities - as well as private organizations, are required, to obtain a radio station license from the Federal Communications Commission if they wish to use a radio transmitter.

The FCC will help you through the licensing process. 

You can find the basic information you need to begin the process at the FCC website. If you are engaged in public safety activities, you can go directly to:

http://www.fcc.gov/pshs/

If you are a business, commercial, or institutional organization, you can go directly to:

http://www.fcc.gov/pshs/

In either case, you will be shown the regulations and the information you will need to gather before you get started - your desired operating frequencies, wideband/narrowband, antenna type and size, power/wattage, etc. You'll also get information on how to obtain the necessary application forms - either in hard-copy or electronic format - and how to proceed.

The FCC website also offers a list of Frequency Coordinators. These are private organizations officially certified by the FCC to help you through the process, and who in most cases will handle the actual filing of your application. With few exceptions, you must apply for an FCC license through a Frequency Coordinator. They are located throughout the country, making it easy for you to find one that is familiar with radio operations in your area.

There are companies who specialize in assisting with licensing radio modems. You may consider contacting one of the following:

Atlas License Company and Data Services 
1-800-252-0529  
http://www.alcds.com

Airwaves Licensing 
1-717-334-0910 
http://www.airwaveslicensing.com

 

1. Setting the Over-The-Air Data Rate

The SkyLine has programmable over-the-air baud rates.  The over-the-air rate is stored in register R2, and is programmed with the ATR2 x command, where x is a number corresponding to the rate.   The are many possible baud rates, but not all rates may be used with all radio modem models.  Consult the following table.

 

Changing the over-the-air data rate will change the sensitivity of the receiver.  Higher-data rates require a stronger signal at the receiver to be properly received.  The default over-the-air data rate for M7 radio modems is 4800 baud for narrow-band versions, and 9600 baud for wide-band versions. 

The maximum over-the-air baud-rate for a narrow-band radio (12.5kHz channel-spacing) is 9600bps. Due to IF filter limitations, the M7 does not work as well at 9600 baud as some other rates. Its performance is optimized for 4800 baud 2-level modulation and 8000 baud 4-level modulation. 

The maximum over-the-air baud-rate for a wide-band model (25kHz channel spacing) is 19200bps. Due to IF filter limitations, it does not work as well at 19200 baud as lower data rates. Its performance is optimized for 9600 baud 2-level modulation.

RV-M7-UC (narrow-band version)

Factory default, set R2 to 3 (4800 baud).

For high-speed operation, set R2 to 4 (8000 baud).

For best range (longest distance), set R2 to 1 (1200 baud)

Other data rates of 0(800bps), 2(2400bps), 3(4800bps), and 7(9600bps) will work, but have a less optimal bit-error-rate vs. receive sensitivity. 

RV-M7-UC-W (wide-band version)

For high-speed operation, set R2 to 5 (9600 baud).

For best range (longest distance), set R2 to 1 (1200 baud)

Other data rates of 0(800bps), 2(2400bps), 3(4800bps), 7(9600bps), and 6(19,200bps) will work, but have a less optimal bit-error-rate vs. receive sensitivity. 

2. Debug Related Commands

Bench Testing

(Must be in command mode to test.   Enter +++ at the keyboard to put unit into config/test mode.)

ATTD  x Various transmit test routines.   
0 = Go back to normal mode. Stops the test. 
1 = Random data transmit. 
2 = Hop up/down one channel 
3 = Force PLL to fast lock mode 
4 = Transmit all 0s 
5 = Transmit all 1s 
6 = Enable the test points on the PCB.  
7 = Transmit CW on center of channel 
8 = Transmit preamble (101010 pattern)

SHOW Display an overview of the configuration.

Ping xxxx Ping another modem over the air.  Transmits a request to xxxx to see if xxxx can hear the sending station. If it does, it answers with a response transmission, containing its ID and the signal strength of the reception. .

ATST Display statistics of how the modem is working.

ATST 1 Display statistics of how the modem’s GPS is working (if installed).

AT$5 Display RSSI.  It will scroll the reading until another character comes in the serial port.

Packet Counter

The packet counter mode will output packet count statistics once per minute.  It will output the number of packets received in the last minute as well as the running total.  T

ATPE     Begin counting and displaying the packet counters every minute

ATPE 1 Reset the packet counters back to zero

ATPE 2 Stop counting and displaying packet counters

Upon power up, the packet counter feature is always disabled.