Sit back, relax and get ready to find out everything you need to know about Lithium Ion and Lithium Iron Phosphate LiFePO4 12V batteries with our resident 12V expert Cahn. Lithium batteries offer a couple of huge benefits over typical lead acid batteries including the fact that they’re super lightweight, they have a high energy density (lots of power in a small package) and they have a much longer cycle life.

In this video we cover the difference between different types of Lithium Ion and Lithium Iron Phosphate batteries, the difference between LiFePO4 and AGM batteries, how Lithium batteries ‘work’ and how to get the most out of them including charging and storage tips. Finally we cover what to look for when doing your own research and focus on how important it is to get a battery with a high quality Battery Management System or BMS.

Why Do We Use LifePO4?

Lithium Iron Phosphate (LiFePO4) batteries are the cheapest, safest lithium chemistry with lighter battery packs, long cycle life, and a maximum output profile, allowing for 90% usable capacity and many years of use. Hams love them!

I Need Power

Ham radio is a hobby that starts simply enough, normally through the purchase of a VHF/UHF handheld transceiver with its own battery pack and charger. Once an amateur radio operator decides that they want to go to more advanced HF and get their General class license (or move to mobile VHF/UHF rigs), that’s where the gear starts getting a little more complicated.

One of the things a new General class ham will find about new HF radios is there’s very little in the way of explaining how to power the more advanced rig. All you get is a funky Molex connector and a pair of bare wires with fuses on them. When I got my first HF rig, a Yaesu FT-857D, I was perplexed that I couldn’t just plug it in to the wall AC outlet.

Many manufacturers do this because they do not know how you will install your new radio. Mobile ones like the 857D I had are intended to be wired to the 12V electrical system of a vehicle. Larger desktop HF radios also use 12V, but the manufacturer does not assume how you’re supplying that 12V or what type of power connector you’ll be using, so they just give you a long pair of black and red wires.

Naturally, a new ham will want to either buy a 12V battery, or a 12V power supply. And not knowing any better, what are the 12V batteries we find everywhere? Car batteries. Sealed lead-acid (SLA) heavy batteries that power everything from motorcycles to boats.

What is a LiFePO4 Battery?

Lithium Iron Phosphate (LiFePO4) batteries are a type of Lithium-ion battery that use lithium iron phosphate as the cathode material instead of lithium nickel manganese cobalt oxide (NMC), lithium nickel cobalt aluminum (NCA), or lithium polymer (LiPo) electrolyte. All lithium-ion batteries are lighter, smaller, and provide more power than an equivalent capacity battery of older chemistry such as SLA.

Among the lithium batteries, it costs less to produce LiFePO4 than other types of lithium-ion chemistries. Iron and phosphates are common elements to find in the Earth’s crust, and have lower toxicity than electrolyte, cobalt, or nickel based chemistries. Moreover, LiFePO4 also does not experience thermal runaway at high temperatures like oxide and electrolyte lithium chemistries do (i.e. LiFePO4 doesn’t vent excessive oxygen to feed a fire and explode at above 150 degrees Celsius), hence LiFePO4 has a reputation as “the safest lithium-ion battery chemistry”. So what can cause a battery to get above 150 degrees C (302 degrees Fahrenheit)? Other than heating one in an oven, a simple short circuit or cell puncture can easily produce this level of heat very quickly.

Another aspect of lithium iron phosphate batteries is they have a longer cycle life than other lithium chemistries. LiPo batteries, the type you find in your cell phone or in small devices, normally have 300 cycles before significantly degrading in performance. NMC lithium batteries, such as popular 18650 cells, can go for about 1000 to 2000 cycles max. LiFePO4 is known under ideal conditions to go to 10000 cycles, but is more commonly expected to do 3000 cycles before degrading to 80% of capacity. Even after that LiFePO4’s are still usable. If you think about it, that’s 8 years of daily battery cycles in typical conditions, and upwards of 20+ years if you treat the LiFePO4 battery well.

Because each cell has a nominal voltage of 3.2V, four of these cells could be put in series to very closely match the profile of a traditional SLA battery. But unlike SLA batteries which get damaged if you drain more than 50% of their capacity, LiFePO4 can deliver 90% of their rated capacity and have safety mechanisms to prevent cell damage.

LiFePO4 Enters the Ham Hive Mind

At a certain point in the late 20-teens, ham radio operators began discovering that portable ops did not require lugging a heavy car battery along. Some hams had already been using RC batteries for their needs, but these would typically provide 11V instead of 12V, and were more dangerous to charge and carry in the field. Right around 2018, I discovered my first lithium iron phosphate battery for QRP operation. It was a 3Ah tiny blue battery from Bioenno. By then many hams had caught on that you could have a lighter, more reliable type of 12V power in the field. LiFePO4 could be discharged till they turn themselves off, could keep their charge for long periods of time, and were smaller for the equivalent amount of amp-hours.

Almost all LiFePO4 batteries have smart balancing and protection technology built into them via a Battery Management System (BMS) board. This prevents over-current, overcharge, over-discharge, short-circuit, and in some cases excessive temperature which enhances the overall battery’s safety.

A growing number of hams found that they could even source the individual parts of a 12V LiFePO4 battery and build one to their own specifications. Early pioneers of this like OH8STN Julian, and K8MRD Mike shared their battery building experience in YouTube videos. Picking the cells, capacities, BMS specifications, current flow estimations, and safety accessories was a hobby in itself.

Naturally, many people do not want to work with soldering and spot-welding, so many manufacturers and resellers (especially Chinese companies, since they have somewhat of a monopoly on LiFePO4 cell production) offer ever-cheaper finished batteries of varying qualities. These are originally intended to be automotive batteries, so if you see anything marketed as “B-rated” cells, those are batteries that did not pass the automotive tests or are used/recycled.

Charging Profiles

LiFePO4 charges best at 14.6V, which translates to getting each cell to 3.65V in a 4S pack. Many Lithium Iron Phosphate batteries will not engage cell-balancing, which is the process of bringing each individual cell to 3.65V as close as possible, if charged below 14.6 volts. Granted, you will get more cycle life out of your battery if you charge it at 14.2V, but its BMS may never be engaged and you won’t get all its potential performance. LiFePO4 batteries like constant voltage/constant current charging, and cut themselves off when full (via the BMS).

Compare this to a SLA charger for typical 6-cell 12V batteries that has concepts of bulk charge, float charge (a.k.a. trickle charge), absorption charge and equalization charge, all these different profiles that vary voltage and current from 13.8V to 14.7V. Can one use a SLA charger on a LiFePO4? Yes, but it is not good for it. These different charging profiles don’t agree with LiFePO4 batteries and will either not charge it to its potential or degrade it over time. SLA batteries like to be charged up constantly, especially when not in use. LiFePO4 likes to be charged then left alone. LiFePO4 has a very small self-discharge rate and can be stored for months, even years, and still work great.

Beyond 12 Volts

The 12V LiFePO4 battery market is just the tip of the iceberg. Many different industries are looking into safe, reliable, long-term energy storage in higher voltages. In the early 2020’s we have seen increasing numbers of rack-mounted 24V, 36V, and 48V systems in the tens of kilowatt-hour range that are intended use in off-grid/backup power systems, boats, and RV’s. Other products include higher voltage battery packs for use in EV bikes, and EV cars, uninterruptible power supplies, and emergency response mobile power trailers.

Even if you are not installing a whole-home backup power wall, many portable solutions are popping up. With the increasing regularity of natural disasters, I have received many inquiries about what is the best portable backup for a power outage during a storm or California fire. I recommend products such as Jackery, EcoFlow, Bluetti, EG4 for all-in-one portable power, as well as, of course, building your own setup with prismatic LiFePO4 cells, solar panels, and inverters.

So if you’ve ever wondered what LiFePO4 is about, why is it different from LiPo, and why not just get a cheaper SLA battery, hopefully this article has given you some insight into this modern battery chemistry.

Source Credit: AD6DM

“How Ham Radio Operators Are Helping with Disaster Communication”:

I. Introduction

The purpose of the article “How Ham Radio Operators Are Helping with Disaster Communication” is to highlight the critical role that amateur radio, or “ham radio,” operators play in facilitating communication during times of disaster. The article emphasizes the unique advantages of ham radio, such as its ability to function independently of traditional communication infrastructure, and the dedicated and skilled operators who volunteer their time to provide essential communication services in emergencies.

In today’s world, where natural disasters and other emergencies are becoming more frequent and severe, the need for reliable communication is more important than ever. Ham radio operators have proven to be an invaluable resource in these situations, providing a backup communication system when traditional methods fail. The article also touches on the importance of educating the public about the benefits of ham radio and encouraging more people to get involved in this valuable hobby, thereby increasing the pool of skilled operators who can assist in times of crisis.

Overall, the article’s relevance lies in its emphasis on the importance of reliable communication during disasters and the critical role that ham radio operators play in facilitating such communication. By raising awareness of this valuable resource and encouraging more people to get involved, the article aims to help ensure that communities are better prepared to handle emergencies when they arise.

Ham radio, also known as amateur radio, is a hobby that involves the use of radio communication equipment to communicate with other amateur radio operators around the world. Ham radio operators can communicate via voice, Morse code, digital modes, and other techniques.

One significant advantage of ham radio is that it can operate independently of traditional communication infrastructure, such as phone lines, internet connections, and cell towers. This makes ham radio an essential tool in emergency communication when these traditional methods may be unavailable due to damage or overload.

In times of disaster or emergency, ham radio operators play a crucial role in providing communication services. They can quickly set up their equipment and communicate with other operators to relay messages, provide updates, and coordinate rescue efforts. Ham radio operators often work alongside first responders and emergency management teams to provide a backup communication system in case of infrastructure failure.

Moreover, ham radio operators receive special training and certification to ensure they are skilled in operating the equipment and can handle emergency situations effectively. They also typically maintain close relationships with other operators around the world, which can be critical in providing assistance during international emergencies.

Overall, the significance of ham radio in emergency communication lies in its ability to provide a reliable and independent communication system during times of crisis when traditional infrastructure may be unavailable. The skills and dedication of ham radio operators make them an essential part of emergency response efforts and help ensure that critical communication services remain available to those who need them most.

II. Ham Radio in Disaster Communication

Ham radio, also known as amateur radio, is a form of communication that operates on frequencies reserved for non-commercial use by licensed individuals. In emergency situations, ham radio operators can use their equipment and expertise to provide communication services when traditional infrastructure, such as phone lines and cellular networks, are disrupted.

In disaster communication and emergency response, ham radio operators can perform a variety of tasks, such as:

1. Providing situational awareness: Ham radio operators can act as the eyes and ears on the ground, providing real-time updates on the situation in affected areas. This information can be used by emergency responders to allocate resources and prioritize rescue efforts.
2. Coordinating rescue efforts: Ham radio operators can relay information between different emergency response teams, such as fire departments, police departments, and medical teams. They can also assist in search and rescue operations by relaying messages between the rescuers and those who need help.
3. Establishing communication links: In disaster-stricken areas, traditional communication infrastructure may be damaged or destroyed. Ham radio operators can set up portable communication stations and antennas to establish communication links between affected areas and the outside world.
4. Providing backup communication: Ham radio can serve as a backup communication system when traditional infrastructure fails. For example, ham radio operators can provide communication links for emergency responders who are working in remote areas or in areas where traditional communication methods are not available.

Overall, ham radio plays a critical role in disaster communication and emergency response. By providing reliable and resilient communication services, ham radio operators can help save lives and protect property during times of crisis.

Ham radio, or amateur radio, plays a critical role in providing reliable communication in disaster-stricken areas where traditional communication infrastructure may be damaged or overwhelmed. When disasters strike, such as hurricanes, earthquakes, or wildfires, communication is essential for coordinating rescue and relief efforts, and ham radio operators are often the only means of communication available.

One of the primary advantages of ham radio is its ability to function independently of traditional communication infrastructure. Ham radio equipment can operate on batteries, generators, or even solar power, allowing it to function even when the power grid is down. Ham radio operators can set up their equipment quickly and communicate with other operators to relay critical information, such as the location of survivors, the status of infrastructure, and updates on rescue and relief efforts.

Ham radio operators can also provide a backup communication system for first responders and emergency management teams. In many cases, traditional communication systems may become overwhelmed or damaged, making it difficult or impossible for first responders to communicate with each other or with people in need of assistance. In these situations, ham

III. Emergency Communication Organizations and Networks

Several organizations and networks are dedicated to emergency communication, providing support and coordination for ham radio operators during times of crisis. Here are three examples:

1. Amateur Radio Emergency Service (ARES) is a program sponsored by the American Radio Relay League (ARRL) that organizes licensed ham radio operators to provide emergency communication services to public service agencies during times of crisis. ARES volunteers undergo training and can be deployed to assist local emergency management teams, hospitals, and other organizations in need of communication support.
2. Radio Amateur Civil Emergency Service (RACES) is a program sponsored by the Federal Emergency Management Agency (FEMA) that utilizes amateur radio operators to provide emergency communication support to local, state, and federal government agencies during times of crisis. RACES operators are authorized by the government to operate on certain frequencies during emergency situations and undergo specialized training to work with public service agencies.
3. The National Traffic System (NTS) is a network of amateur radio operators in the United States that provides a system for handling and relaying messages during times of emergency or disaster. The NTS operates using standardized procedures and protocols, allowing messages to be relayed quickly and efficiently throughout the network.

These organizations and networks provide essential support and coordination for ham radio operators during emergencies, ensuring that communication services are available when they are needed most. By working together with first responders and emergency management teams, ham radio operators can provide a critical lifeline to those affected by disasters and help facilitate rescue and relief efforts.

Emergency communication organizations and networks, such as the Amateur Radio Emergency Service (ARES), Radio Amateur Civil Emergency Service (RACES), and the National Traffic System (NTS), play a crucial role in disaster communication. These organizations provide trained volunteers, resources, and coordination for ham radio operators during emergencies, ensuring that communication services remain available when traditional infrastructure may be unavailable.

The importance of these organizations lies in their ability to provide a coordinated and efficient communication system during times of crisis. ARES and RACES volunteers can work alongside first responders and emergency management teams, providing communication support and relaying critical information. NTS operators can handle and relay messages quickly and efficiently, ensuring that information is distributed to those who need it most.

In addition, these organizations and networks provide essential training and resources for ham radio operators to prepare for emergency situations. Volunteers receive specialized training and are often equipped with emergency communication kits, enabling them to quickly set up their equipment and provide communication services when needed.

The contributions of these organizations and networks to disaster

IV. Communication Equipment and Technology

Ham radio operators use a variety of communication equipment and technology to provide reliable communication during disasters, often relying on portable and mobile radios, antennas, and power sources. Here is a brief overview of the equipment used:

1. Portable Radios: Ham radio operators use portable radios that are designed to be lightweight and easily transportable, making them ideal for use in emergency situations. These radios often feature multiple bands and frequencies, allowing operators to communicate with other radios over long distances.
2. Mobile Radios: Mobile radios are installed in vehicles and can be used to provide communication support while on the move. These radios are often more powerful than portable radios and can be used to communicate with a wider range of operators.
3. Antennas: Antennas are critical components of ham radio equipment, allowing operators to transmit and receive radio signals. Antennas come in many different shapes and sizes and can be designed for use in specific situations or environments.
4. Power Sources: Ham radio operators rely on a variety of power sources to keep their equipment functioning during disasters. Portable radios may be powered by batteries or solar panels, while mobile radios may be connected to a vehicle’s battery or a separate generator.

In addition to this equipment, ham radio operators also use specialized software and communication protocols to ensure that messages are transmitted efficiently and accurately. By leveraging this equipment and technology, ham radio operators can provide essential communication services during disasters, helping to coordinate rescue and relief efforts and provide critical information to those in need.

Setting up communication infrastructure in disaster-stricken areas can be a significant challenge due to a variety of factors, including:

1. Damage to existing infrastructure: Disasters such as earthquakes, hurricanes, and wildfires can cause significant damage to existing communication infrastructure, including cell towers, power lines, and telephone lines. This damage can make it difficult or impossible to establish reliable communication channels in affected areas.
2. Limited access to resources: In some disaster-stricken areas, access to resources such as power, fuel, and transportation may be limited, making it difficult to deploy and operate communication equipment. This can also make it challenging to maintain communication infrastructure over an extended period of time.
3. Geographic and environmental obstacles: Some disaster-stricken areas may be difficult to access due to challenging terrain or environmental factors such as flooding or extreme weather conditions. These obstacles can make it difficult to deploy communication equipment and can also affect the quality of communication signals.
4. Security concerns: In some disaster situations, security concerns may arise, making it difficult to establish communication infrastructure and ensure the safety of personnel and equipment.
5. Communication protocol incompatibility: Communication infrastructure may not be compatible with other protocols, which can lead to confusion, delay, and errors.

Overcoming these challenges requires careful planning and coordination between emergency responders, communication experts, and other stakeholders. Ham radio operators can play an important role in bridging communication gaps by providing alternative communication channels and support during emergencies. Additionally, ongoing investments in communication infrastructure can help mitigate the impact of disasters on communication services, making it easier to provide reliable communication services to those in need.

V. Ham Radio in Specific Disasters

Ham radio operators play a crucial role in providing communication support during a range of disasters, including hurricanes, earthquakes, and wildfires. Here are some examples of their contributions:

1. Hurricanes: During hurricanes, ham radio operators often work with emergency response agencies to provide communication support to affected communities. They can provide critical updates on weather conditions, evacuation orders, and relief efforts. In the aftermath of a hurricane, ham radio operators can also provide communication support to first responders and aid organizations, helping to coordinate search and rescue efforts and deliver supplies to those in need.
2. Earthquakes: In the event of an earthquake, ham radio operators can provide communication support when traditional communication channels such as phone and internet lines may be down. They can relay information about the location and severity of the earthquake, as well as any damage or injuries. Ham radio operators can also assist with search and rescue efforts by relaying information between first responders and those in need of assistance.
3. Wildfires: Ham radio operators can assist with communication efforts during wildfires by providing information about the location and severity of the fire, as well as evacuation orders and shelter locations. They can also provide support to first responders by relaying information about the location of hotspots and the status of firefighting efforts.

Ineach of these disasters, ham radio operators can provide critical communication support when traditional channels are unavailable or overloaded. Their ability to operate independently of traditional communication infrastructure makes them an invaluable asset in emergency situations.

1. Hurricane Katrina (2005): During Hurricane Katrina, which struck the Gulf Coast in 2005, ham radio operators were critical in providing communication support to affected communities. When traditional communication infrastructure was damaged or destroyed, ham radio operators were able to provide updates on the storm’s progress and relay critical information about rescue and relief efforts. Ham radio operators also helped to coordinate medical evacuations and communicate with other emergency response agencies.
2. Nepal Earthquake (2015): In 2015, a 7.8-magnitude earthquake struck Nepal, killing over 8,000 people and causing widespread destruction. Ham radio operators from around the world volunteered to provide communication support to the affected communities. They set up temporary communication networks and helped to coordinate search and rescue efforts, as well as provide updates on the status of relief efforts.
3. California Wildfires (2017): In 2017, a series of devastating wildfires swept through California, destroying thousands of homes and forcing tens of thousands of people to evacuate. Ham radio operators played a critical role in providing communication support to affected communities. They relayed information about evacuation orders, provided updates on the status of the fires, and helped to coordinate relief efforts.
4. Hurricane Maria (2017): When Hurricane Maria struck Puerto Rico in 2017, ham radio operators were among the first to provide communication support to the island. They helped to relay critical information about the storm’s progress, as well as provide updates on the status of relief efforts. Ham radio operators also helped to coordinate search and rescue efforts and assist with medical evacuations.

These are just a few examples of the important role that ham radio operators play in disaster communication. Their ability to operate independently of traditional communication infrastructure makes them a valuable asset in emergency situations, and their dedication to providing communication support to affected communities is truly remarkable.

VI. Emergency Preparedness

Emergency preparedness is crucial for effective disaster communication and response. When a disaster strikes, it is often too late to start preparing communication infrastructure and systems. Therefore, it is important to have a plan in place ahead of time and to regularly practice and update that plan.

Here are some reasons why emergency preparedness is so important:

1. Communication infrastructure can be damaged or destroyed in a disaster: During a disaster, traditional communication infrastructure such as phone lines and internet services can become damaged or destroyed. Having backup communication systems, such as ham radios, can help ensure that communication channels remain open.
2. Time is of the essence: In a disaster, time is of the essence. The faster emergency response agencies can communicate with each other and with affected communities, the more lives can be saved. A well-prepared emergency communication plan can help facilitate rapid communication and coordination.
3. Effective communication can prevent chaos: Without effective communication, disaster response efforts can quickly devolve into chaos. Clear communication channels and coordinated efforts can help prevent confusion and ensure that resources are distributed efficiently.
4. Preparation can save lives: Ultimately, emergency preparedness can save lives. When communication infrastructure is in place and emergency response agencies are well-coordinated, response efforts can be more effective and efficient, allowing for faster and more effective aid to those in need.

In short, emergency preparedness is critical for effective disaster communication and response. It can help ensure that communication channels remain open, facilitate rapid communication and coordination, prevent chaos, and ultimately save lives.

Ham radio operators can take several steps to prepare for emergencies and be ready to provide communication support. Here are a few key strategies:

1. Obtain the necessary equipment: Ham radio operators should ensure they have the necessary equipment, including radios, antennas, and power sources. They should also keep spare parts and backup equipment on hand in case of equipment failure.
2. Develop a communication plan: Ham radio operators should develop a communication plan that outlines who they will communicate with, what frequencies they will use, and what protocols they will follow. This plan should be tested regularly to ensure it works in practice.
3. Participate in emergency communication networks: Ham radio operators can participate in networks such as the Amateur Radio Emergency Service (ARES) and the Radio Amateur Civil Emergency Service (RACES). These networks provide training, support, and coordination during emergencies.
4. Stay informed: Ham radio operators should stay informed about emergency situations in their area and be ready to respond if called upon. They can do this by monitoring local news and weather reports and participating in emergency drills and exercises.
5. Practice good communication skills: Ham radio operators should practice good communication skills, including clear and concise communication, active listening, and proper radio etiquette. This can help ensure that communication channels remain clear and effective during emergencies.

By taking these steps, ham radio operators can be prepared to provide communication support during emergencies and help ensure that critical communication channels remain open.

VII. Training and Licensing

Ham radio operators who want to participate in disaster communication and response must obtain the appropriate training and licensing. Here are the key requirements:

1. Licensing: In order to operate a ham radio, individuals must obtain a license from the Federal Communications Commission (FCC). There are three levels of licenses, each with increasing privileges and responsibilities. The entry-level license, called the Technician Class license, requires passing a written exam that covers basic operating procedures, regulations, and electronics theory. The next level, called the General Class license, requires passing a more advanced written exam that covers additional operating procedures and regulations. The highest level, called the Extra Class license, requires passing an even more advanced written exam that covers advanced operating procedures, regulations, and technical theory.
2. Training: In addition to obtaining a license, ham radio operators who want to participate in disaster communication and response should seek out training in emergency communication procedures and protocols. There are several organizations that offer such training, including the Amateur Radio Emergency Service (ARES), the Radio Amateur Civil Emergency Service (RACES), and the National Traffic System (NTS). These organizations provide training on topics such as emergency communication protocols, message handling, and net control operations.
3. Ongoing Education: Ham radio operators must also participate in ongoing education to maintain their licenses. This includes staying up-to-date with changes to regulations and procedures and continuing to develop their knowledge and skills in radio communication.

Overall, obtaining a ham radio license and obtaining training in emergency communication procedures and protocols are key requirements for ham radio operators who want to participate in disaster communication and response. By obtaining these credentials and continuing to develop their knowledge and skills, ham radio operators can play a critical role in providing communication support during emergencies.

• Explain how ham radio operators can develop their skills and knowledge in emergency communication

VIII. Challenges and Opportunities

While ham radio operators play a critical role in disaster communication, they face several challenges that can make it difficult to provide effective support. Here are some of the key challenges:

1. Interference: One of the biggest challenges ham radio operators face is interference from other radio signals. During a disaster, many different organizations may be using radios to communicate, which can create interference that makes it difficult for ham radio operators to establish communication. Additionally, natural phenomena such as solar flares and geomagnetic storms can also create interference that disrupts radio communication.
2. Limited Resources: Another challenge facing ham radio operators is limited resources. In a disaster situation, resources such as power and communication infrastructure may be damaged or destroyed, making it difficult to establish and maintain communication. Ham radio operators must be able to operate with limited resources,

Ham radio operators have the opportunity to contribute to disaster communication and response in innovative ways. Here are some examples:

1. Digital Modes: Ham radio operators are increasingly using digital modes, such as packet radio and Winlink, to provide reliable communication during emergencies. These modes allow operators to send and receive messages using computers and software, which can be more efficient than traditional voice communication.
2. Drones: Ham radio operators can use drones equipped with cameras and radios to provide communication support in areas that are difficult to reach or inaccessible. Drones can be used to establish communication links between remote locations and provide real-time video feeds of disaster zones.
3. Mobile Applications: There are several mobile applications that allow ham radio operators to access communication networks and resources during emergencies. For example, the Ham Radio Deluxe app provides access to digital modes and logging software, while the ARES Connect app allows operators to access emergency communication protocols and resources.
4. Social Media: Ham radio operators can also use social media platforms, such as Twitter and Facebook, to provide updates on disaster response efforts and communicate with other operators and emergency responders.

Overall, ham radio operators have many opportunities to contribute to disaster communication and response in innovative ways. By leveraging new technologies and tools, operators can provide critical support during emergencies and help to ensure that communication remains reliable and effective.

IX. Future of Ham Radio in Disaster Communication

Ham radio has been an essential tool for disaster communication for over a century, and it will likely continue to play a vital role in emergency response efforts in the future. Here are some potential ways ham radio may evolve in the coming years:

1. Integration with other technologies: Ham radio operators may increasingly integrate their communication efforts with other technologies such as drones, satellites, and the internet of things. This integration could lead to more efficient and effective communication networks that can provide real-time updates and monitoring.
2. Greater use of digital modes: Digital modes such as packet radio and Winlink are becoming increasingly popular among ham radio operators. As these technologies continue to develop, they could become even more reliable and efficient, allowing for faster and more secure communication during emergencies.
3. Expansion of emergency preparedness training: As more people become interested in ham radio as a tool for emergency communication, we may see an expansion of emergency preparedness training programs. These programs could help more people to become licensed ham radio operators and prepare them to provide communication support during emergencies.
4. Continued collaboration with emergency responders: Ham radio operators will likely continue to collaborate closely with emergency responders such as firefighters, police, and medical professionals. This collaboration could lead to more effective emergency response efforts and better coordination between different groups during disasters.

Overall, the future of ham radio in disaster communication is likely to involve a combination of new technologies, expanded training programs, and closer collaboration with emergency responders. As disasters become more frequent and severe, the importance of reliable communication will only continue to grow, making ham radio a critical tool for emergency response efforts around the world.

There are potential opportunities and challenges that may arise as ham radio evolves in disaster communication in the coming years:

Opportunities:

1. Improved communication networks: The integration of ham radio with other technologies such as drones and satellites could lead to more efficient and effective communication networks during emergencies.
2. More efficient and secure communication: The use of digital modes and the development of new technologies could lead to faster, more secure, and reliable communication during emergencies.
3. Increased interest in emergency preparedness: The expansion of training programs and the growing interest in ham radio as a tool for emergency communication could lead to more people becoming prepared for emergencies and willing to help during disasters.
4. Enhanced collaboration with emergency responders: The continued collaboration between ham radio operators and emergency responders could lead to better coordination and more effective emergency response efforts.

Challenges:

1. Interference and limited resources: As more people use ham radio during emergencies, there may be more interference and limited resources available, which could hinder communication efforts.
2. Changing technology: As technology continues to evolve, ham radio operators may need to keep up with these changes, which could require additional training and resources.
3. Dependence on volunteers: Ham radio communication networks often rely on volunteers who may not be available during emergencies, which could pose challenges in maintaining communication networks.
4. Regulatory issues: Regulatory issues could pose challenges for ham radio operators, such as changes to licensing requirements or spectrum allocation.

Overall, while there are potential challenges that may arise as ham radio evolves in disaster communication, there are also opportunities for improved communication networks, more efficient and secure communication, increased interest in emergency preparedness, and enhanced collaboration with emergency responders.

X. Conclusion

The article discusses the role of ham radio in disaster communication and response, highlighting its significance in providing reliable communication during emergencies. It describes the various organizations and networks dedicated to emergency communication, such as ARES, RACES, and NTS, and their contributions to disaster communication. The article also explains the communication equipment and technology used by ham radio operators, as well as the challenges of setting up communication infrastructure in disaster-stricken areas. Additionally, the article provides case studies and examples of successful ham radio communication in disasters such as hurricanes, earthquakes, and wildfires.

It emphasizes the importance of emergency preparedness in disaster communication and response, and describes how ham radio operators can prepare for emergencies and be ready to provide communication support. The article also discusses the training and licensing requirements for ham radio operators who want to participate in disaster communication and response.

Furthermore, it discusses the challenges facing ham radio operators in disaster communication, such as interference, limited resources, and changing technology, as well as potential opportunities for ham radio operators to contribute to disaster communication and response in innovative ways.

Finally, the article looks into the future of ham radio in disaster communication and speculates on how it might evolve in the coming years, highlighting potential opportunities and challenges that may arise.

Ham radio plays a crucial role in disaster communication and response. During emergencies, traditional communication methods such as cell phones and the internet may become unreliable or even completely unavailable. In these situations, ham radio operators can provide a lifeline of communication that can save lives and help coordinate relief efforts.

Ham radio’s ability to operate independently of traditional communication infrastructure makes it a valuable asset in disaster situations. It allows communication to be established and maintained even when other methods are unavailable, providing a vital link between emergency responders, relief organizations, and those affected by the disaster.

Moreover, ham radio operators often work alongside other emergency communication organizations, such as ARES, RACES, and NTS, to provide a coordinated and effective response. Their expertise and training in communication technology and emergency procedures enable them to quickly establish communication networks, even in the most challenging circumstances.

Getting involved in ham radio and its emergency communication organizations and networks is an excellent way to contribute to the community and prepare for emergencies. Whether you’re interested in becoming a licensed ham radio operator, volunteering with an emergency communication organization, or simply learning more about how you can help in times of disaster, there are many opportunities to get involved.

By joining a local ham radio club, you can connect with other enthusiasts and learn about the latest technology and techniques in the field. You can also participate in drills and exercises to practice emergency communication procedures and gain valuable experience.

Additionally, volunteering with organizations such as ARES, RACES, and NTS can provide you with opportunities to support disaster response efforts and serve your community in times of need.

In conclusion, getting involved in ham radio and emergency communication organizations can not only help you develop valuable skills and knowledge but also make a real difference in times of crisis. So, consider exploring these opportunities and see how you can contribute to the important work of emergency communication and response.

Source Credit: Medium

The Wilderness Protocol is a suggestion that those outside of repeater range should monitor standard simplex channels at specific times in case others have Emergency or priority calls. The primary frequency is 146.52 MHz with 52.525, 223.5, 446.0 and 1294.5 MHz serving as secondary frequencies. This system was conceived to facilitate communications between hams that were hiking or backpacking in uninhabited areas, outside repeater range. However, the Wilderness Protocol should not be viewed as something just for hikers. It can (and should) be used by everyone anywhere repeater coverage is unavailable. The protocol only becomes effective when many people use it.

The Wilderness Protocol recommends that those stations able to do so should monitor the primary (and secondary, if possible) frequency every three hours starting at:

• 7 AM, local time, for 5 minutes…
• 10 AM
• 1 PM
• 4 PM
• 7 PM
• 10 PM

Additionally, those stations that have sufficient power resources should monitor for 5 minutes starting at the top of every hour, or even continuously.

NOTE*** Placing 146.52 MHz , 52.525, 223.5, 446.0 and 1294.5 MHz in your Scanner would help.

Priority transmissions should begin with the LiTZ signal. ( LONG TONE ZERO )
CQ-like calls (to see who is out there) should not take place until four minutes after the hour.

UHF/VHF Simplex Wilderness Protocol

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The Wilderness Protocol is simply a recommendation that those outside of repeater range monitor standard simplex channels at specific times in case others have priority or emergency calls. “FM & Repeaters”, June 1996 QST, p. 85.

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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.

The Wilderness Protocol --

The Wilderness Protocol is a dedicated effort to insure emergency communications help either in areas beyond normal repeater coverage, or in the event local repeaters are off-the-air and not reachable
in an emergency situation.

The purpose of this initiative is to offer stations outside or without repeater range capability an opportunity to be heard when needed the most!

The Wilderness Protocol suggests that radio operators in the Amateur service monitor standard simplex channels at specific times in case of Emergency or priority calls.

The primary frequency to monitor 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, or outside repeater range an alternative opportunity to be heard.

NOTE- Though it’s mainly used in the wilderness settings, it’s NOT just for hikers, back packers, or similar situations….it is also available for ANYONE to use at ANYTIME assistance is needed.

Recommended procedures for “Wilderness Protocol”

MONITOR THE STANDARD CALLING FREQS: *146.520* and/or any of the SECONDARY FREQUENCIES.(52.525, 223.500, 446.00, 1294.500)

MONITOR TIMING: Every 3 hours starting from 0700 HRS ..on the hour until 5 (five) minutes past the hour.(7:00-7:05 AM, 10:00-10:05 AM, …, 10:00-10:05 PM).

ALTERNATE TIMING: 0655 to 0705, Etc 5 before till 5 after.. (to allow for differences in peoples watch settings). You can always listen for longer if you want.

ENHANCED MONITORING: Fixed stations or portable stations with enough battery power levels LISTEN EVERY HOUR. (Obviously Continuous Monitoring is also an option.)

LISTENING / MONITORING: Listen to the calling frequencies until 4 minutes past the hour, then make a few calls asking if there are stations listening that may need assistance. This calling traffic should only start at 4 minutes after the hour preceded by listening for 30 seconds… Unless of course you’re the one making an emergency call. LISTEN FIRST- CALL CQ with short transmissions. LISTEN FIRST! – always a good idea!

NOTE- 146.52 IS A CALLING FREQUENCY…. Make your Calls, and then move off the frequency so others can use the frequency. Suggested frequencies to move to; 146.55, 146.43, etc. etc.

PRIORITY TONE SIGNALS: Suggested for Priority Radio Transmissions ONLY.

USE the LONG TONE ZERO (abbreviated LiTZ). Begin calls for assistance with about 10 seconds of TONE with the LiTZ signal. Do this by keying up and holding down the zero key to continuously transmit the zero DTMF tone ( hence: LONG TONE ZERO ). Then proceed to make your emergency call. This should help those listening to recognize that an emergency or priority call is coming through.

Lastly, remind people of the protocol at your club meetings and on radio nets. It a good thing to know.

Source Credit: Tcares

Let’s take a look at several different power supply technologies to power your rig. How do you get a low-noise, high-current 13.8 volts? Price, performance, power, and even weight are things to consider.

How many amps does your rig draw? Do you need to over-provision current? Is that cheap ebay-supply going to smoke your expensive radio? No everyone can afford an expensive linear power supply, so let’s take a look at some reliable alternatives.

[NOTE: this originated as a Linux User Net discussion topic for Aug. 5, 2019]

Indroduction

The term “SDR” — Software Defined Radio — has been widely used and misused, both for descriptive and marketing purposes. As a result, it has can mean many things, depending on the context in which it is used, as well as the perspecive of the speaker.

If someone tells you, “I have an SDR”, you have to dig deeper to discover what that “SDR” actually is. Part of the confusion comes from the fact that “software-defined radio” originally described a process, not an object.

Usage

I have come up with a list of seven possibile meanings — there may be more.

1) A radio with DSP

People sometimes cofuse Digital Signal Processing with SDR. The difference is that DSP works on audio signals, not radio signals. Many analog radios use DSP in their audio stages. Note that a true SDR almost always will encorporate DSP. So, this is not actually SDR.

2) Digital control of a radio

Again, not really SDR. I hear this most often applied to QRP rigs, such as the uBitx. The radio itself is fully analog, but it is controlled by a digital device, such as an Arduino or similar microcontroller board. This is nothing new, of course — virtually every ham rig produced in recent years has come with a digital interface. What is new is that the control device is open to be programmed by the user. I believe this is the source of confusion with SDR.

3) A USB device

• Here we get into radios are true SDRs, with full analog-to-digital (and possibly vice-versa) at the RF stage.
• This includes a large range of devices, from inexpensive plug-in dongles to sophisticated radio development devices.
• Most commonly receive-only, but could be a transceiver
• Output might be an I/Q stream for processing by another device. E.G., RTL-SDR.
• Might include a FPGA (Field Programmable Gate Array) to process the I/Q from the ADC, so the output is audio, plus perhaps metadata such as spectrum data for display. In a development device, the FPGA could be open for programming by the user.

4) SDR-in-a-box

Here the radio is fully software-defined in the inside, but externally appears to be, and functions as, a traditional radio. These rigs are essentially designed to be drop-in replacements for older analog units, sporting the cutomary knob and button controls, along with legacy interfaces such as serial ports. It looks and feels so much like an analog radio that you wouldn’t know it’s digital inside without being told. Examples: Icom IC-7300, Yaesu FTDX-101D.

5) SDR box + built-in Windows PC

This is an all-in-one rig that includes a full MS Windows PC internally. That gives it the capability of running various ham software inside the box, rather than in a connected PC. Hook up monitor, keyboard, and mouse, and you have a complete shack-in-a-box. Example: Expert Electronics MB1.

6) SDR box + server

• Again, a single box with traditional controls, but it also acts as a network server so that other digital boxes can connect to it, either to remotely control or be controlled.
• All signal conversion and processing is done onboard, with audio and metadata transferred over a computer network.
• Example: Elecraft K4 (I think with a Linux server inside).

7) SDR server only

• As above, all signal conversion and processing is done on board, with audio and metadata transferred over a computer network.
• No external user controls. All control is performed on networked computers.
• In essence, the network is the radio.
• Possible advantage is open API or software that allows anyone to program interfaces for them.
• Examples:
  • FlexRadio. Linux server inside. They produce a custom control unit, built around a Windows CE tablet. Also have grafted that unit to the front of servers to produce an all-in-one unit; still connected via Ethernet. Control software (SmartSDR) is proprietary, but the API (Application Programming Interface) it uses is open and well-documented.
  • ANAN transceivers: Fully open source software, inside and out. Apache Labs offers a Raspberry Pi-based control unit.

An aside

“SDR radio” — another redundant acronym?

I’m always on the lookout for new examples of redundant acronyms, where people pronounce the acronym as a word and follow it with the word that the final letter of the acronym stands for. Examples are “PIN number” and “ATM machine”. I recently added “NIC card” to my list (thanks to KA7PLE).

“SDR radio” might be one — or it might not. It can be argued that if “SDR” describes the process of manipulating RF signals with software and the word “radio” describes an object that functions within the accepted meaning of “a radio”, then “radio” has two different meanings – and so there is no redundancy, even though it sounds that way.

Source Credit: KC7MM Wiki

C4FM stands for Continuous 4-level Frequency Modulation. (FM), and is the actual digital modulation of the radio signal used in System Fusion over VHF/UHF. Wires-X is the node linking/voip technology that allows nodes to link across the Internet.

For WIRES-X, an amateur node station connecting to the Internet is used as the access point and connects the wireless communication to the Internet. Users’ stations can communicate with other amateur stations all over the world using a node within the radio wave range.

WIRES-X supports the C4FM digital and the clear and crisp voice technology enables high sound quality. By repeating C4FM digital data as it is via the Internet, users can enjoy clear voice communications even if they are thousands of miles away each other.

Utilizing the digital communication, the WIRES-X operation is simple, easy and user friendly.
Varieties of the new functions as well as voice communications expands opportunities for enjoyment of ham station operation.

WIRES-X automatically connects to nodes and rooms via the Internet. No more need to verify connection IDs or transmit cumbersome DTMF connection codes.

Information about nodes and rooms is exchanged via C4FM Digital signaling. Thanks to automatic reconnection to the previous contact, all you need to do is press PTT and start talking.
Easily search for new nodes and rooms, and initiate communication promptly when you find an ID that captures your interest.

Yaesu FT-70D, finding and saving Wires X rooms into memory

A repeater, in concept, is not really a complicated device. A repeater is an automatically controlled transmitter and receiver that simply transmits what the receiver hears simultaneously. Imagine having a receiver on one channel, and a high power transmitter on the other, and then holding the microphone of the transmitter in front of the speaker of the receiver. Now make the operation fully automatic. Any user that can be heard by the receiver has the effectiveness of the high power transmitter at his control.

In general, repeater systems are usually located in places of high elevation (on tall towers, on top of mountains or tall buildings) and are equipped with large and efficient antennas, extremely low loss feedlines, and a transmitter and receiver that is very durable, rated for continuous duty, and built to be as immune as possible to interference.

The end result? People using a repeater get much greater range from their radio equipment than would be possible talking from radio to radio. This is how an individual with a portable walkie-talkie (handheld) transceiver can communicate with people many miles away with good clarity.

Repeaters are used in police, fire and ambulance service communications (commonly called “Public Safety”), Commercial (Business) Communications, Federal, State and Local Government agencies, Emergency Communications, and by Amateur Radio Operators. Repeaters can be powered by the regular commercial power lines, or they can be connected to multiple sources of power, including batteries and/or generators for when commercial power is lost. Repeaters can be built that are extremely power efficient and may run exclusively from batteries; recharged by solar, wind or water power.

Here’s a link to a solar-powered amateur repeater: http://www.polkcounty.org/ham/

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What is Simplex

Simplex is point to point communications without the use of a repeater. Simplex operation utilizes the same frequency for receive and transmit, like a CB radio. I.E. Portable to Portable or Mobile to Mobile. The commercial 2-way world calls Simplex operation ‘Talk Around” because you are talking around the repeater, not through it.

There are such things as Simplex Repeaters. These machines listen on the frequency for activity, when it recognizes something it will begin to record that activity for a pre-determined time; usually 1 minute. A slang term for these is a “parrot repeater”. After the activity ceases or the time has expired, the unit will repeat what it has recorded. This method of communications is somewhat cumbersome over a conventional repeater; because you are forced to listen to what you said earlier in time and the channel usage is problematic as you never know when someone else is recording; however it should not be discounted as these types of systems can be very beneficial.

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What is Duplex

The simple explanation of full duplex operation is like the telephone, where both people can talk at the same time. In contrast, a pair of handhelds operate in half-duplex mode because only one person can talk at a time. Since the ‘repeater’ listens and talks at the same time in relaying your message, it operates in full duplex mode.

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How does a Repeater work

At first glance, a repeater might appear complicated, but if we take it apart, piece by piece, it’s really not really so difficult to understand. A basic repeater consists of several individual pieces that, when connected, form a functional system. Here’s a simple block diagram of a repeater:

The collection of the antenna, the feedline, the duplexer, and the interconnecting cables is frequently called the “antenna system”.

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Antenna

Most repeaters use only one antenna. The antenna simultaneously serves both the transmit and receive RF (Radio Frequency) signals that are going in to and out of the repeater. It’s generally a high performance, durable, and very efficient antenna located as high on a tower or structure as we can get it. Antenna systems of this type can easily cost $500 or more, and that’s not including the feedline. On the other hand, when properly installed and maintaned they can last from 10 to 25 years.

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Feedline

The feedline on most repeaters isn’t just a piece of standard coax cable, it’s what’s called Hardline. This stuff is more like a pipe with a center conductor than a cable. It’s hard to work with and very expensive. So why do we use it? Performance! The signal loss is much lower in hardline than in standard cable, so more power gets from the antenna to the receiver and weaker signals can be received. A hard rule is that once any percentage of a received signal is lost that you can’t get it back – ever.

Remember, the signal at a repeater site doesn’t just travel a few feet to an antenna like in a mobile rig. It may go hundreds of feet up the tower to the antenna. Just for fun check out the specs on a roll of coax some time and see how many dB of loss you’ll get from 200 feet of cable, and remember 3 dB is 1/2 of your power, and 10 dB is 90% of your power. Hardline also tends to be more durable than standard cable, which increases reliability and helps us minimize the financial expense, and the tower climbs to replace it.

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Duplexer

This device serves a critical role in a repeater. To make a long story short, the duplexer separates and isolates the incoming signal from the outgoing and vice versa. Even though the repeaters input and output frequencies are different, the duplexer is still needed. Why? Have you ever been in a place where there’s lots of RF activity, and noticed the receive performance of your handheld radio degrades to some degree? This is called desensitization, or desense, and it’s a bad thing on a repeater. The receiver gets noisy or gets desensitized to the point of total deafness from the strong RF signals being radiated in its vicinity and confused about which signal it should receive.

The result is poor receive quality, or in extreme cases, complete lack of receive capability. Keep in mind that in this example, the radios are picking up radiated power from one another and that’s enough to cause trouble. Now imagine how much trouble there will be if you not only have the transmitter and receiver close together, but connect them to the same antenna!

Transmitting only a few hundred kHz away in frequency would blow away the input to the receiver if the equipment was simply connected together with a Tee. That’s where the duplexer comes in; it prevents the receiver and transmitter from ‘hearing’ one another by the isolation it provides. And the more isolation the better.

A duplexer is a device that is referred to by several different names like cavities or cans. A duplexer has the shape of tall canisters and is designed to pass a very, very narrow range of frequencies and to reject all others. There is some loss to the system because of the duplexer (called the “insertion loss”), however, the advantage of being able to use a single antenna and a single feedline usually outweighs the drawbacks.

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Receiver

Receives the incoming signal. This receiver is generally a very sensitive and selective high performance one which helps weaker stations to be heard better by the repeater. It’s also where CTCSS (Continuous Tone Coded Squelch System) or “PL” decoding takes place. More on this later.

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Transmitter

Most machines have a transmitter composed of two parts: an ‘exciter’ and a power amplifier. The exciter created low level RF energy on the proper frequency and then modulates it with the audio. The power amplifier stages simply boosts the level so the signal will travel further. Transmitters come in two types: intermittent duty and continuous duty. One that is rated for continuous duty is preferred.

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The “Station”

The term “Station” is used to describe a stationary two way radio set; which includes the transmitter, receiver and sometimes the control circuitry. One example is the dispatch radio for a fire department. A ‘Repeater Station’ is a station designed to be used as a duplex repeater.

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Controller

This is the brain of the repeater. It handles station identification (through either CW or voice), activates the transmitter at the appropriate times, controls the autopatch, and sometimes does many other things. Some machines also have a DVR (Digital Voice Recorder) for announcements and messages. The controller is a little computer that’s programmed and optimized to control a repeater.

The various models of controllers have different useful features like speed-dial for phone patches, a voice clock, facilities to control a remote base or linking, etc. The controller gives the repeater its ‘personality’. Whenever you’re using a repeater, you’re interacting with its controller. In the early days of repeaters the controller was a large chassis full of relays and timers. These days a controller is most often a microcomputer based unit.

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What is a Phone Patch or Autopatch? AKA “The Patch”

Many repeaters have a feature that allows you to place a telephone call from your radio. Phone calls are generally restricted to the local calling area of the repeater to avoid long distance charges to the repeater’s sponsors. If in doubt, ask if the repeater has an open patch and how to access it.

When using the patch it is common courtesy to announce your intentions, e.g. “This is N3XZY on the patch”. This may help to prevent anyone from keying up while you are trying to use the function. In most areas when you are finished with the patch the accepted protocol is to announce it, e.g. “This is N3XZY clear the patch”.

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DVR
A DVR is a Digital Voice Recorder, or in modern terms a “voice mail” system for the repeater. Usually it’s an option that is installed into the controller.

Repeater Operation
Operating using a repeater isn’t difficult. A good source of info is the ARRL Repeater Directory. It’s an inexpensive book with repeater listings all over the US. It contains frequency, offset and whether the repeater is + or – in shift (see “offset” below), whether or not it requires a PL tone, and other features (like an autopatch, or repeater-to-repeater linking).

What is Offset
In order to listen and transmit at the same time, repeaters use two different frequencies. On the 2 meter ham band these frequencies are 600 kHz apart. As a general rule in the USA, if the output frequency (transmit) of the repeater is below 147 MHz then the input frequency (listening) is 600 kHz lower. This is referred to as a negative offset. If the output is 147 MHz or above then the input is 600 kHz above. This is referred to as a positive offset. However in any given area the offset rules can be different.

Virtually all ham radios sold today set the offset once you have chosen the operating frequency. As an example one repeater output is 145.270 MHz. The input, or the frequency it listens on is 144.670 MHz (600 kHz below). If you have your radio tuned to 145.270 MHz with the offset enabled, when you push the PTT switch (Push-To-Talk) your radio automatically transmits on 144.670 MHz. When you release the PTT to listen, the radio reverts back to 145.270 MHz to listen on the repeater’s output frequency.

Standard Repeater Input/Output Offsets
Band	Offset
6 meters (50-54 MHz)	No real nationwide standard, it varies widely. Most common are -500 kHz, -600 kHz or -1.0 MHz
2 meters (144-148 MHz)	Up and down 600 kHz, depends on frequency
1.25 meters (222-224 MHz, also called “220”)	Down 1.6 MHz
70 cm (440 MHz, also called “UHF”)	Up or down 5 MHz, depends on local area usage
33 cm (900 MHz)	-25 MHz
23 cm (1200 MHz)	-20 MHz

Note: There are exceptions to the above so check local repeater listings.

Why do Repeaters use an Offset
To use a repeater a user station must use a different transmit frequency than receive frequency. This is a form of duplex, or two frequency operation. It is known as half-duplex as you do not receive and transmit at the same time but normally use the push-to-talk button on your microphone to switch between the two.

Most repeater installations use the same antenna for transmit and receive. Without having an offset the repeater would simply hear itself when it was transmitting on the same frequency it was listening on. Even with the offset, the two frequencies are close enough that antenna system isolation is required. Again, this isolation is afforded by the duplexer.

What is Carrier Access, Tone Squelch, CTCSS or a PL Tone
Carrier Access, or Carrier Squelch means that the repeater is looking for a carrier on the receiver frequency to open the squelch. A circuit called a Carrier Operated Switch (COS) or Carrier Operated Relay (COR) senses the squelch opening, and tells the repeater that there is a carrier on the input. The controller keys the transmitter, thereby repeating the signal.

Continuous Tone Coded Squelch System, or CTCSS, is a radio communications industry standard signaling scheme. It provides an electronic means of allowing a repeater to respond only to stations that encode or send a very precise audio tone at a very low level superimosed on the transmitter along with the microphone audio. The CTCSS system is used to prevent the repeater receiver from responding to unwanted signals or interference (it’s looking for both the carrier and the tone before the signal is considered as valid).

If a repeater is “in tone mode” that means it requires a CTCSS tone to activate the repeater. If it is in “Carrier mode” then it is ignoring the CTCSS decoder, if there is one. Modern repeater controllers offer a way to switch back and forth, even automatically, between the two modes. Originally there were 32 standard tones, now there are 37.

Some manufacturers offer more, but most repeaters use one of the original 32 so as to allow the older radios to use the system. Aftermarket tone generators from several differnet manufacturers allow any station to be set up to transmit a CTCSS tone. The tones are in the 67-250 Hz range and are called sub-audible, because they’re below the normal voice audio range of 300-3000 Hz. This doesn’t mean you can’t or won’t hear them; they can be quite noticeable depending on the radio you’re using.

PL, an acronym for Private Line, is Motorola’s proprietary name for CTCSS. General Electric uses the name “Channel Guard” or CG for the same system. Other names, such as Call Guard, Quiet Channel or Quiet Tone are used by other manufacturers.

In days of old, repeaters that used PL were considered to be closed or private. This is no longer the case as tone operation has become more the rule instead of the exception. Uninformed people use CTCSS to “solve” interference problems. It doesn’t. It just covers them up, or hides them. The unwanted signal is still on the repeater input, the tone decoder simply prevents the repeater from making it obvious.

Of course, everything these days is digital. A later system called Digital Coded Squelch (DCS) uses 85 different sub-audible digital bit streams. Motorola uses the name Digital Private Line, or DPL for this. Other manufacturers use different names. DPL is gaining in popularity since more radios now come with it as a standard feature.

How do you call someone on an Amateur Repeater?
First, listen to make sure that the repeater is not already in use. Then listen some more. If you are a new ham that has never used a repater before it might pay to listen for a week or so and see what goes on, who seems to be the “regular users”, and if you know any of them, perhaps from the local ham club meeting.

When you are satisfied that the repeater is not in use, begin with the callsign of the station you are trying to contact followed by your callsign. e.g. “W3ABC this is N3XYZ”. If you don’t establish contact with the station you are looking for, wait a minute or two and repeat your call.

If you are just announcing your presence on the repeater it is helpful to others that may be listening if you identify the repeater you are using. e.g. “This is N3XYZ listening on 6-2-5”. This allows people that are listening on radios that scan several repeaters to identify which repeater you are using (and therefore which microphone to pick up to answer you).

If the repeater you are using is a busy repeater you may consider moving to a simplex frequency (transmit and receive on the same frequency), once you have made contact with the station you were calling. Repeaters are designed to facilitate communications between stations that normally wouldn’t be able to communicate because of terrain or power limitations. If you can maintain your conversation without using the repeater, going “simplex” will leave the repeater free for other stations to use.

Repeater Etiquette
The first and most important rule is LISTEN FIRST. Few things are more annoying than someone that “keys up” in the middle of another conversation without first checking to make sure the repeater is free. Saying that your volume control was down too low and you didn’t hear any conversation is no excuse – it just says that you didn’t chack your own station before you used it. If the repeater is in use, wait for a pause in the conversation and simply announce your callsign and wait for one of the other stations to acknowledge your call.

When you are using the repeater leave a couple of seconds between exchanges to allow other stations to join in or make a quick call. Most repeaters have a “Courtesy Tone” that will help in determining how long to pause. The courtesy tone serves two purposes. Repeaters have a time out function that will shut down the transmitter if the repeater is held on for a preset length of time (normally three or four minutes). This ensures that if someone’s transmitter is stuck on for any reason, it won’t hold the repeater’s transmitter on indefinitely.

When a ham is talking and releases the push-to-talk switch on their radio, the controller in the repeater detects the loss of carrier and resets the time-out timer. Many of the modern computerized controllers allow the owner to program a “beep” to indicate that the timer is reset. This beep is called the courtesy beep, or the courtesy tone.

If you wait until you hear this beep (normally a couple of seconds) before you respond, you can be sure that you are pausing a suitable length of time. After you hear the beep, the repeater’s transmitter will stay on for a few more seconds before turning off. This is referred to as the “carrier delay”, or the “hang in timer”. The length of the delay will vary from repeater to repeater but the average is about 2 or 3 seconds. You don’t have to wait for the transmitter to drop off the air before keying up again, but you should make sure that you hear the courtesy tone before going ahead.

Note: If you don’t wait for the beep the time-out timer to may not reset. Some repeater clubs have a rule that if you time-out the repeater you get to buy a round of coffee at the next ham club meeting.

What is “Doubling” ?
When two stations try to talk at the same time the signals mix in the repeater’s receiver and results in a buzzing sound or squeal. When you are involved in a roundtable discussion with several other stations it is always best to pass off to a specific person rather than leave it up it the air. e.g. “W3ABC to take it, this is N3XYZ” or “Do you have any comments Fred?, this is N3XYZ”. Failing to do so is an invitation to chaos and confusion.

It is for this very reason that when groups hold scheduled Nets (network of hams meeting on air at a predetermined time), they assign a Net Control station. The Net Controls job is to make sure there is an orderly exchange and that all stations get a chance to speak. Listen to a local net and you will get an idea of the format and how the Net Control juggles the various stations and traffic.

It’s a job almost anyone can handle, but as you will discover, some are much better at it than others. And if you try your hand at being Net Control for a night, you will discover just how hard it can be! (and you will gain a lot of respect for those that have the knack to do it and make it sound easy). A well run net is both informative and entertaining!

What is a Control Operator?
The Part 97 of the FCC Rules requires all stations in the Amateur Service that are capable of operating unattended must be monitored for proper operation while in the unattended mode. This monitoring function is accomplished by a control operator. The Control Op can be the licensee of the station or anyone he or she chooses. In many cases, he or she also ends up being the person that answers questions about the repeater.

What is White Noise?
White noise is a term used to describe a spectrum of broad band noise generated in a receiver’s detector and sampled to control the receiver’s squelch. When you open the squelch control and hear the rushing noise from the speaker, this is white noise. When the receiver is in carrier squelch mode the squelch circuit uses the presence of that noise to decide that the signal has gone away and it should mute the receiver speaker.

When the receiver is in tone squelch mode it uses the abscence of the tone AND the presense of the noise to indicate loss of signal. The “squelch tail” is that burst of white noise that you hear that starts when someone unkeys and ends when the squelch circuit actually mutes the receiver audio (some people mistakenly use the term to refer to the carrier delay mentioned above).

I hope this article has explained the Repeater in enough detail that you understand what it is and how to use it. If there is any part of this article that seems vague or confusing, please write me and I’ll do my best to explain it better.

Email Kevin: kuggie //at// kuggie //dot// com

Credits: Repeater Builder

The word “grounding” — meaning a connection to the Earth — is casually applied to so many different purposes in Amateur Radio, it’s no wonder there are many opinions and misconceptions about it. “Bonding” is a less familiar term to most amateurs. In the electrical sense, bonding simply means “to connect together” so that voltage differences between pieces of equipment are minimized.

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Why Are Grounding and Bonding Important?

There are three needs we are trying to satisfy:

• AC safety: protect against shock hazards from ac-powered equipment by providing a safe path for current when a fault occurs in wiring or insulation.

• Lightning protection: keep all equipment at the same voltage during transients and surges from lightning and dissipate the lightning’s charge in the Earth, routing it away from equipment.

• RF management: prevent unwanted RF currents and voltages from disrupting the normal functions of equipment (also known as RF interference or RFI).

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Why Is “Grounding” So Complicated?

The very word — grounding — means a lot of different things depending on who you’re talking to and what you’re talking about. Isn’t grounding just connecting equipment to the Earth? That is certainly one definition of grounding.

The British use the terms “earthing” and “protective earth conductor” which are more exact references to what the connection is for. But the layer of soil and rock at the Earth’s surface is not a magic zero-voltage point into which we can pour any amount of electric charge where it safely disappears! The current’s strength and frequency, soil characteristics, whether it is wet or dry, the length of the path to the Earth connection and through the soil — all of these affect what our equipment experiences at the “ground” connection.

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Station Grounding for Amateur Radio – Ask Dave

Grey or gray line propagation is a form of HF radio propagation apparent at dawn and dusk where signals traveling along the line are heard at much higher strengths.

Grey line or gray line propagation is a form of radio signal propagation that provides surprisingly long distance radio communications at dawn and dusk sometimes when other forms of ionospheric propagation may not be expected to provide signal paths of these distances.

Grey line propagation is only present around dawn and dusk and therefore it cannot be used to support global radio communications at any time. Accordingly it tends to be used chiefly by radio amateurs and a few other users who can accommodate the timing and other limitations of its availability.

Grey line propagation basics

For grey line propagation signals travel along the grey or twilight zone between night and day. This is area where night and day meet and it is also known as the terminator. In this region signals on some frequencies are attenuated much less than might normally be experienced and as a result signals can be received at surprisingly high levels over very long distances – even from the other side of the globe.

The improved propagation conditions around the grey line are most noticeable primarily on the lower frequency bands in the HF portion of the spectrum where the level of ionization in the D layer has a much greater effect on signals that on those frequencies higher up.

The diagram below shows how the illumination remains on the F region much longer than on the D region, and this creates a situation where the D region has faded away, but the F region remains intact.

In reality, the D region fades before dusk as the illumination from the sun reduces around dusk at the Earths surface. The level of ionization in the D region drops very quickly around dusk and after dark because the air density is high and recombination of the free electrons and positive ions occurs comparatively quickly.

This occurs while the level of ionization is still high within the F layer, which gives most of the radio propagation for long distance radio communications. This occurs because the F region is much higher in altitude, and as the Sun sets it remains illuminated by the Sun’s radiation for longer than the D region, which is lower down. Also recombination of the ions takes longer because the air is very much thinner at the altitude of the F region compared to that of the D region.

The same occurs in the morning as the Sun rises. The F region receives radiation from the Sun before the D region and its ionization level starts to rise before that of the D region. As the level of the D region ionization is low, this means that the degree of attenuation to which the lower frequency signals are subjected to is very much less than in the day. This also occurs at a time when the F region ionization is still very high, and good reflections are still achievable. Accordingly this results in much lower overall path losses around the grey line than are normally seen.

In terms of the diagram above, the altitude of the D and F regions have been highly exaggerated to show the mechanism behind the grey line. This means that the fading of the D region starts to occur well before dusk and the F region remains in place until after dusk – and grey line propagation occurs around the region of dusk and dawn.

In fact, when looking at the region of the radio terminator it should be remembered that there are a variety of variables that mean that it does not exactly follow the day time / night time terminator as seen on the Earth’s surface. The ionized regions are well above the Earth’s surface and are accordingly illuminated for longer, although against this the Sun is low in the sky and the level of ionization is low. Furthermore there is a finite time required for the level of ionization to rise and decay. As there are many variables associated with the “radio signal propagation” terminator, the ordinary terminator should only be taken as a rough guide for radio signal propagation conditions.

Although it may be obvious to mention, grey line propagation can only exist for stations at locations that fall along the grey line or terminator. This significantly limits the number of areas for a given station at a particular location to set up long distance communication, although there will be slight changes over the course of the year for many stations.

Frequencies affected by grey line propagation

Frequencies that are affected by this form of propagation are generally limited to frequencies up to about 10 MHz. Frequencies higher in frequency than 10 MHz tend to be attenuated to only a minor degree by the D region and therefore there is little or no enhancement around dusk and dawn by this mechanism.

Grey line propagation is particularly noticeable on lower frequencies, for example the 3.5 MHz amateur radio band. Normally signals may be heard over distances of a few hundred kilometers in the day, and possibly up to or two thousand kilometers at night for those stations with good antennas.

Grey line propagation regularly enables long distance radio communication contacts to be made with stations the other side of the globe at very good strength levels.

The optimum times are normally around the spring and autumn equinoxes as neither end of the link is subject to the propagation extremes of summer and winter. It is at these times of year that long distance radio communication can be established with stations on the other side of the globe at remarkably good signal strength levels.

Similar mechanisms for higher frequencies

It is still possible for higher frequency signals to be affected by a grey line type enhancements. This occurs as a result of the fact that a propagation path is opening in one area and closing in another giving a short window during which the path is open on a particular frequency or band of frequencies.

Looking at the MUFs over the course of the day can demonstrate the way in which this occurs. The level of ionization in the F layer falls after dusk, and rises at dawn. This results in the MUF falling after dark.

Accordingly, stations experiencing dawn find the MUF rises and those experiencing dusk find it that it falls. For frequencies that are above the night time MUF, and for stations where one is experiencing dusk and the other dawn, there is only a limited time where the path will remain open. This results in a similar effect to that seen by the lower frequency grey-line enhancement.

Grey line enhancements over the course of the year

The path of the grey line changes during the course of the year. As the angle subtended by the Sun’s rays changes with the seasons, so the line taken by the terminator changes. This results from the fact that during the winter months, the Northern Hemisphere of the earth is titled away from the Sun, and towards it during the summer months.

The converse is obviously true for the southern hemisphere. In addition to this the width of the grey line also changes. It is much wider towards the poles because the line between dark and light is less will defined as a result of the fact that the Sun never rises high in the sky at the poles. It is also much narrower at the equator. This results in grey line propagation being active for longer at the poles than at the equator.

Grey line propagation provides an opportunity for long distance radio communication contacts and links to be made, often with stations the other side of the globe. Signals travel along the grey line, or terminator and suffer comparatively little attenuation. An opening via grey line propagation may only last for half an hour, but it gives the opportunity for radio communication to be established between stations as far away as the other side of the globe.