Repeaters
What are Repeater's and what frequencies do they operate on?
What are Repeaters
- An amateur radio a repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. Many repeaters are located on hilltops or on tall buildings as the higher location increases their coverage area, sometimes referred to as the radio horizon, or “footprint”. Amateur radio repeaters are similar in concept to those used by public safety entities (police, fire department, etc.), businesses, government, military, and more. Amateur radio repeaters may even use commercially packaged repeater systems that have been adjusted to operate within amateur radio frequency bands, but more often amateur repeaters are assembled from receivers, transmitters, controllers, power supplies, antennas, and other components, from various sources.
- In amateur radio, repeaters are typically maintained by individual hobbyists or local groups of amateur radio operators. Many repeaters are provided openly to other amateur radio operators and typically not used as a remote base station by a single user or group. In some areas multiple repeaters are linked together to form a wide-coverage network, such as the linked system provided by the Independent Repeater Association[1] which covers most of western Michigan, or the Western Intertie Network System (“WINsystem”) that now covers a great deal of California, and is in 17 other states, including Hawaii, along with parts of four other countries, Australia, Canada, Great Britain and Japan. Wikipedia
Repeater Frequencies
- Repeaters are found mainly in the VHF 6 meter (50–54 MHz), 2 meter (144–148 MHz), 1.25-meter band (11⁄4 meters) (220–225 MHz) and the UHF 70 centimeter (420–450 MHz) bands, but can be used on almost any frequency pair above 28 MHz. In some areas, 33 centimeters (902–928 MHz) and 23 centimeters (1.24–1.3 GHz) are also used for repeaters. Note that different countries have different rules; for example, in the United States, the two meter band is 144–148 MHz, while in the United Kingdom (and most of Europe) it is 144–146 MHz. Wikipedia
National Calling Frequency
- A national calling frequency in the USA is a radio frequency that is widely accepted and understood to be a place to start communicating with other hams.
- This frequency is established for each RF band under the voluntary US band plan and is not regulated by the FCC. It is routinely monitored by any number of radio amateurs and is likely to result in a response when calling CQ or Mayday or SOS.
For new hams who are likely to get started in local VHF/UHF operation, the national calling frequencies to be concerned with are 2m and 70cm FM simplex (non-repeater). These are 146.520MHz and 446.000MHz, respectively, and should be included in your radio’s scanned channels. If you regularly use 1.25m, 33cm and/or 23cm bands, there are national simplex calling frequencies defined per the band plan for you to look up. - Be aware that the national calling frequency for whatever mode and activity is only a place to start communicating. Protocol and common courtesy require that once contact is established, you move to another frequency (QSY) to leave the calling frequency open for others to use.
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Wilderness Protocols
Wilderness Protocol Monitoring:
- The purpose of this initiative is to offer stations outside repeater range an opportunity to be heard when it is needed the most!
- The Wilderness Protocol suggests radio operators in the Amateur service should monitor standard simplex channels at specific times in case of Emergency or priority calls.
- The primary frequency monitored is 146.52 MHz; secondarily or alternatively 52.525, 223.5, 446.0 and 1294.5 MHz respectively. The idea is to allow communications between hams that are hiking or backpacking in uninhabited areas, outside repeater range an alternative opportunity to be heard.
NOTE- Though it’s mainly usedin the wilderness settings, it’s NOT just for hikers, back packers, or similar situations….it is also available for ANYONE to use at ANYTIME… Folks may need assistance outside of camping as well!
Recommended procedures for “Wilderness Protocol”
Simplex frequencies: 146.52 <-- primary 446.0 223.5 52.525 1294.5 Monitor at least 07:00 - 07:05 10:00 - 10:05 13:00 - 13:05 16:00 - 16:05 etc.; if possible, monitor every hour. Priority/Emergency transmission: begin with 10 seconds of DTMF "0" (this is called LiTZ, "Long Tone Zero", and is a good idea for repeaters as well). Routine transmission: wait until four minutes after the hour.
SARnet: Statewide Amateur Radio Networking in Florida
Florida's Ham Radio Emergency Communications Network
WHAT IS SARNET?
The Statewide Amateur Radio Network (SARnet) is a network of linked UHF voice repeaters that serves the State of Florida. The repeaters are operated by their local trustees and the network that connects them together does not interfere with the local use of the repeaters. These UHF repeaters were specifically chosen in part because the voice traffic on them is light. This helps ensure that long conversations and rag-chews are rare on SARnet since any SARnet traffic brings up ALL of the repeaters on the network. But always remember when using these UHF frequencies that the government has primary use of the amateur spectrum near 440MHz. See this discussion on the government use of the band.
The key to what makes SARnet work so well is that this network uses dedicated bandwidth that is separate from the internet. Statewide connectivity is achieved without the use of any commercial telecommunications services. SARnet does not use the internet, cellular telephones, or land lines. SarNET
WHY WAS SARNET STARTED?
- The state of Florida Department of Transportation is continually investigating new IP technologies for use in improving its own voice radio network and to meet its mandate to provide inter-operable communications with other state agencies and public safety entities. Instead of using their live voice radio network as an ongoing test bed for these new IP technologies, the FDOT has partnered with the amateur radio community to use their radio systems throughout the state as part of a test bed to support the FDOT’s research. The benefit for the FDOT is that they gain valuable knowledge about how to install, operate, troubleshoot, expand, upgrade, and maintain a sophisticated IP radio network. With SARnet, the FDOT can conduct their research without jeopardizing their live voice radio system and creating potentially unsafe and counter productive conditions for the FDOT personnel who work on the state’s highways every day. In exchange for supporting this research, the amateur radio community can talk across the state using the same amateur radio equipment they use everyday. The fact that the FDOT network that connects these amateur radio repeaters together is a stand-alone carrier class microwave network means that SARnet is much more likely to remain operational during a severe weather event like a hurricane that might cause disruptions to the internet, cellular telephone and other commercial communication services. SARnet
IS SARNET ONLY FOR EMCOMM?
- No. SARnet is a network of amateur repeaters owned mostly by non-emcomm affiliated hams. So it is not just for emergency communications. That being said, the creators of the network behind SARnet are active in public safety communications, both commercial and amateur, and they have an understanding of what SARnet can do for emergency communications in the state of Florida.
- During a significant emergency event, SARnet may be called upon for support, through an official state emergency request, and radio traffic in and out of an affected area may become heavy. Under such a scenario, It is hoped that all of the local repeater trustees in the affected area will agree to let their repeaters continue to be used as part of SARnet. During such an emergency, if a controlled net is called, it will be by hams working with the county and state EOCs, not SARnet personnel. We have enough to do keeping the network running. SarNET
