HAM radio

What is Amateur radio?

• May be non-commercial, but we're experts. "The expert radio community".

• Shortwave radio just receives across multiple bands 0 to ad infinitum including digital.

• CB — Citizens Band radio used by truckers and RVs

• Runs the gamut the whole spectrum of radio, no matter how it's split up. We're all using wireless communications. Regardless of whether it's a radio, or phone, bluetooth, etc.

• The concept for our purposes is the use of radio on public bands.
  • Must not be unencrypted

• • • Also includes websites that use radio to feed data. Cannot use SSL HTTPS

• • Some are digital

• Radio waves always propogate at speed of light, shorter wavelengths have higher frequencies — inverse relationship.

• If you want to dip your toe in there are many publicly accessible receivers around the world that are available online like http://websdr.org

Short history

• Marconi, first radio transmission in San Francisco during the 1890s Spanish American War from a Liberty Ship off the coast using spark gap communication, to the Cliff House.

• Started out with broadcasters who didn't want the general public to use the bands led to breaking up of the spectrum. There are many parts of the spectrum. They started out using very low frequency 1, 2 cycles per second. How waves travel depends on atmospheric conditions.

Current radio technology

• Current radio works off of bouncing off of ionesphere — launch angles come into play. Impacted by weather and sun spot activity.

• Most am radio operators use low frequency, or higher frequency VHF, UHF using public reserved areas of the band.

• In Bay Area working on resilient internet networks utilizing radio for disasters.

• Because of advances in technology the amount of power / features available has increased in relationship to form factor. However there are legal limits to power of devices — 1500 Watts.
  • A 1500 watt transmitter (same as a microwave oven) can communicate across the world. A 10 watt device can communicate across town.
  • Your use case determines what device / power you use. Tailored to specific needs/circumstances.

Repeaters

• Can be used to boost a single. Often based on high points like Mt Tam, Sutro Tower, etc. Can be leveraged to boost signals of lower power devices

The "Go Kit" demonstration

• A portable radio. In the amateur radio world there are many uses.

• Demonstration of various components and set up

• Antennae
  • Antennae must match your device. An improperly matched attennae may damage your transmitter. It must match the frequency that your transmitter. In some case a low frequency transmission requires a very long antennae, however there are ways to mitigate this using things lik a "load", "matching transformer", "coil".
  • How you position the antennae — proximity to the ground, etc — will impact distance you can communicate. Also can be factored into the type of terrain you're trying to communicate across.
  • Elevation makes a difference to reach. Also salt water, being close to the ocean is highly reflective and can help boost your signal.
  • Battery
    • Typically doesn't use wall power
  • Many new transmitters use very little power, can be run for a 1 week without charging.
  • Portable 10 watt radio
    • Microphone
    • Built in speaker
    • multi-frequency band tuner

• 7 Mhz spectrum 40 meters

Emergency comms

• Part of the purpose of amateur radio is emergency communications. Operators often are chatting, but it's a useful way to test equipment.

• Example of wild fires in N. California due to utilities. No electricity, power. Phone, and mobile cell phone tower networks are very brittle. Batteries in cell towers are only good for 3 *5 days. Land lines can also go down.

• Radio is the last communication option, and became extremely important during the wild fires.

• EPURB — emergency position beacons that help to locate lost /stranded hikers, boats.

Digital radio

• Different ways in which radio waves can be translated into sound, compared to AM / FM bands

• Digital DMR (Digital Mobile Radio, same as HD radio) and newer, more open protocols encodes voice into digital. Effective system that helps to clarify sound

• Packeting can be used to send text.
  • Early packets were being used to send text messages over radio when voice was not possible.
  • Many different protocols exist to compress data in packets.
  • WSJTX transmitter receiver software transmits callsign and location based on a gridded map. Transmit from computer into radio. Handshake to say hello/goodbye.

Uses by Movement

• Location reports on threats

• Disasters

• Hurricane Helene in N. Carolina -*communicating important info like open gas stations

• • Information Technology Disaster Resource Network** deployed to disaster areas. Leveraged Starlink. Provide first responders and community with internet access, VOIP access.

• If your org/affinity group is concerened with op sec then amateur radio may not be for you. Anyone can be listening in, and HAM radio operators may out you to Feds if you're encrypting info, or raises suspicion.

How to become an amateur radio operator

• In most countries you need to get a license from a government body. In US the FCC, different classes of operators:
  • Lowest level technicians license, no more complicated than a driver's license exam. Limited to UHF/VHF bands
  • Very easy to get a license, can do tests online, or in most cities
  • You'll receive a call sign from the FCC
  • General class license if you want to communicate across borders
  • Op Sec issues: FCC will publish address of all licensees, but you can use P.O. Box, or create an association or club if you want to mask your location. Someone who is determined to find your location can triangulate your location