VHF Data Radio
Very High Frequencies (VHF) have been used for voice and data radio communications since the middle of the last century. Bands withing the frequency range of136-174MHz are used throughout the world for reliable wireless data communications.In the United States and in many other countries, the 136-174 MHz range is used for commercial wireless communications. Raveon has data radios in these bands:A)136-155MHzB) 150-174MHz
VHF Radio Frequencies
The two major data radio modem bands used worldwide are the Ultra High Frequency (UHF) band and the Very High Frequency (VHF) band. Raveon provides data radio modems in both the VHF and UHF bands. VHF frequency band is ultra long-range. These radios work reliably up to 60 miles, and often have been used 100 miles apart, with omni-directional antennas. With directional antennas, they will work over 200 miles. For long range RF communications, VHF is the best band to use.
VHF and UHF each have advantages and disadvantages to them. There is no one best band. VHF antenna are typically larger that UHF, but in many instances, the communication range will be greater with a VHF system. UHF has a shorter wave length, so the antennas are more compact and less obtrusive.
UHF signals may penetrate foliage better, and will reflect off of rock and other obstructions very well. UHF will also work indoors somewhat better than VHF and it penetrates buildings better. In open areas, most users will find that VHF data radios communicate farther than UHF data radios. But in heavily wooded areas, or rough terrain, UHF data radios may work better.
Raveon has many types of VHF radio modems.
The RV-M21 Tech Series of radio modems has a myriad of IO options and many features.
The RV-M8 OEM Radio Module is a low cost high performance HF Radio modem module designed to be incorporated into your products that need reliable and secure data communications over VHF radio channels.
For more details about Raveon’s VHF data radio products, click on the Products link above or visit RaveonTech Products
All Raveon Data Radio modems have many features that make them easy to use, and easy to configure up to make your system reliable and efficient.
Here is a list of many of the features in Raveon’s data radio modems:
Application note AN125 M7 Competitive Features describes these features.
- A variety of frequency bands.
- Small and highly integrated, making it the most economical modem on the market.
- Backed by a 2-year warranty.
- Outstanding receiver sensitivity, and with their programmable data rates, the user may select long-range and slower data or faster-data at reduced sensitivity.
- Dual-Mode. Unique to the M7, it operates in either a Streaming or Packetized modes.
- Integrated Repeater. in Every Unit All M7 modems have integrated store-and-forward repeater capabilities in them.
- Flexible I/O The M7 has more I/O options than any other radio modem.
- 16-bit Modem Addresses The M7 modems in a system may be configured with a 16-bit address and network mask.
- Reliable Data Raveon’s M7 incorporates 16-bit CRCs, and reverse error correction, so that all data that comes out of an M7 is 100% perfect.
- Common Port Similar to all telco/Hayes type modems with the AT command set, the M7 uses a common serial port for operation, configuration, and diagnostics.
- Remote Ping The M7 supports a variety of remote diagnostics, including a remote “Ping” command.
- Auto-Status Reporting An M7 may be configured to automatically and periodically report its status over-the-air.
- TDMA Option Al M7 modems have the option of being ordered with a unique TDMA (Time Division Multiple Access) feature. TDMA orchestrates the transmissions of an entire field of M7 modems to ensure that no two transmissions occur at the same time.
- WMX Communications The Wireless Messaging Exchange protocol is an option to communicate with the radio and send data over the air. WMX features include specifying radio IDs, issuing commands, sending data, and monitoring RSSI.