The Northshore School District, who serves 22,000 Seattle area students announced they were closing all of their 36 schools due to the COVID-19 virus. Northshore Superintendent Michelle Reid said the courses will take place online from Monday March 9, 2020.
Twitter asked its almost 5,000 employees to work from home, and Microsoft Corp. and Alphabet Inc. (Google) have done the same for their employees in the Seattle area.
Amazon Inc., which employs 50,000 people in the Seattle area, asked its employees to telecommute, and Apple just asked that the 12,000 employees at its Apple Park campus in California also work from home.
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With students studying from home and employees working from home, our internet and mobile phone networks are going to be stretched, which can affect your ability to reach emergency responders if you need them.
During September 11, when cellular networks went down due to overload and police and fire brigade command centers were destroyed, amateur or “amateur” radio operators stepped in and allowed emergency responders to communicate with each other and with the public.
The term “ham”, as in “ham-handed”, was applied to new wireless telegraph operators by wireline telegraph operators to imply that their Morse code skills were poor.
What is amateur radio?
Amateur radio is different from commercial radio, public safety radio like police and firefighters, and professional radio used by taxis, airplanes, and ships. The Federal Communications Commission (FCC) reserves blocks of radio frequencies for satellites, emergency services, military and commercial aircraft, commercial radio stations and cell phones.
Amateur radio operators are assigned 27 bands or groups of frequencies, from 1.8 megahertz (MHz), which is just above broadcast radio frequencies, and going up to 275 gigahertz. FM radio stations have numbers on the dial between 88 and 108, which signifies their frequency from 88 MHz to 108 MHz. AM radio stations are always between 540 and 1600 KHz.
These frequency blocks have different attributes, such as how much power can be used to transmit a signal, what equipment and antennas can be used, whether repeaters are allowed, and what frequencies are available.
Amateur radio can transmit voice, text, images, data and Morse code over distances ranging from a city, region, country, continent, the entire world or even in the space. Amateur radio can access satellites, the International Space Station, and can even bounce off the moon.
Amateur radio is administered by the International Telecommunication Union (ITU), which is a United Nations agency. It is the world’s oldest international organization. Individual governments regulate amateur radio within their own borders and issue station licenses and call signs.
In the United States, the American Radio Relay League (AARL) is the national association for amateur radio, and it has over 161,000 members. The ARRL provides books, news, support, information, special operating events, continuing education courses and other benefits for its members.
Types of amateur radio
There are several types of amateur radio:
- Amateur radio (amateur) – 1.8 to 1300 MHz with deviations, base stations can reach 1500 watts, while a typical portable amateur radio is 5 to 8 watts, there are few restrictions on the antennas and you will need ‘a license
- Citizen Band (CB) – 26 – 27 MHz (HF), 11 meter band, 40 channels, power is limited to 4 watts, you do not need a license, CB requires larger antennas due to its longer wavelength compared to VHF / UHF, and CB is susceptible to interference from baby monitors
- Family radio service (FRS) and General Mobile Radio Service (SRGM) – 462 – 467 MHz (UHF), 22 channels, while technically two different types, their frequencies overlap, and in 2017 the FCC changed its rules making the two types even more similar; the FRS block was offered by RadioShack in the 1990s and led to the two pack walkie talkies that were popular, farmers and businesses use GMRS, while you don’t need a license for FRS, you need one for GMRS but there is no test, GMRS can run up to 50 watts but most radios are 3 to 5 watts, GMRS allows repeaters
- Multi-use radio service (MURS) – 151 – 154 MHz (VHF), 5 channels, created in 2000, you don’t need a license, the power is limited to 2 watts, some devices pair with your mobile phone to send short SMS without using the network cellular, allowing for a peer-to-peer radio network.
Of these, ham is the only way to listen and talk to local emergency services. CB, FRS, GMRS, and MURS do not operate on emergency broadcast and local emergency response frequencies.
Frequency and wavelength
Frequency is the number of waves per second, and it is described in Hertz (Hz) which is a wave. When you see k, M, or G before Hz, it represents kilo, Mega, and Giga, where kilogram is 1000, Mega is a million, and Giga is a billion. A radio frequency of 300 MHz would correspond to 300,000,000 waves per second.
Wave length is the physical distance from a point on one wave, such as its peak, to the same point on the next wave. The wavelength and frequency are in inverse proportion, that is, the higher the frequency, the lower the wavelength.
High frequency (HF) is 3 – 30 MHz, Very high frequency (VHF) is 30 to 300 MHz, and Ultra high frequency (UHF) is 300 MHz to 3 GHz. Of the 27 amateur radio bands, the most popular are:
|HF||80||3.5 – 4.0|
|HF||40||7.0 – 7.3|
|HF||30||10.1 – 10.15|
|HF||20||14.0 – 14.350|
|HF||17||18,068 – 18,168|
|HF||15||21.0 – 21.450|
|HF||12||24,890 – 24,990|
|HF||ten||28.0 – 29.70|
|VHF||6||50 – 54|
|VHF||2||144 – 148|
|UHF||70cm||430 – 440|
Most amateur radios focus on just two bands: 2 meters / 144-148 MHz and 70 centimeters / 430-440MHz. These two bands are used by local emergency radio services, such as the Amateur radio emergency service, Civilian Amateur Radio Emergency Service, and Community Emergency Response Teams (CERTs).
Radio canals are like URLs, you don’t describe a website as its IP address (220.127.116.11), instead you describe it as “whitehouse.gov”. When people use channel 19 on CB radio, they are actually referring to the frequency 27.185 MHz.
The attributes of wavelengths are that longer wavelengths travel farther, and shorter wavelengths can penetrate buildings. Since the higher the radio frequency, the shorter the wavelength, the 2-meter VHF band can travel farther, but the 70cm UHF band is more effective in making its way through windows and the doors.
Longer wavelengths travel farther than the horizon as they bounce off the atmosphere, mountains, and even the moon. Since an FCC technician’s license, which you’ll find out below, does not allow HF, VHF is most popular among amateur radio enthusiasts.
When Hurricane Maria wiped out cellular networks in Puerto Rico in 2017, amateur radio operators working with VHF mobile radios and speaking on the 2-meter band allowed emergency responders to communicate with each other.
What gives ham radio its reach are repeaters, which are a bit like cell phone towers. Repeaters receive a nearby signal, then broadcast it again with greater power and clarity.
Repeaters are usually located on top of a hill or tall building and are free to use. They are usually created and maintained by a local ham radio or operator. A repeater can move your signal up to 50 miles, but if transmitted by a number of repeaters, your signal can cover an entire country.
A repeater cannot receive and broadcast on the same frequency at the same time. Therefore, they use two different frequencies slightly offset from each other, one for reception and the other for broadcast.
Although some repeaters are solar or generator powered, most depend on the electrical grid. Therefore, in an extreme emergency, these may not be available.
Amateur radio configurations
All amateur radios are composed of a transmitter receiver which sends and receives radio signals, a power supply and an antenna. The three types of amateur radios are:
- Portable radios – also called Handitalkies or HT, the most popular are the Baofeng UV-5R and BF-F8HP.
- Mobile radios – are installed in a vehicle such as a CB radio, they are usually mounted in the dashboard of a vehicle, glove box, or under a seat, and they have a wired microphone that goes all the way to the driver’s seat. Mobile radios have at least double the signal range of a portable radio due to the more battery power and a larger antenna. The antenna can attach to a car’s hood, roof, or tailgate, and magnetic mounts are popular because you can remove the antenna when you don’t need it.
- Base station radios – are usually installed in your home and have a large stationary antenna. The antenna is the most critical part of a base station, and it should be at least 1/4 the size of the wavelength you want to use. The 70cm UHF band only needs a 7 inch antenna.
Amateur radio licenses
There are three levels of ham licensing, and each requires testing and lasts for 10 years. The levels differ depending on how many frequencies you can access.
- Technician (entry) – gives you access to the above amateur groups 30 MHz, including the popular 2 meters and 70 centimeters bands
- General – allows you to access higher frequency bands at lower frequency and longer wavelength, better for long distances
- Additional (advanced) – allows you to broadcast on any amateur frequency.
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