Radios as alternative ways of communication

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We all seem to agree that there's value in off-the-grid comms.

In practice, how do people use these radios in these kinds of situations?

Difficult situation - tightly regulated.

Discuss ways of using radio spectrum that might be at odds with local regulations. We'll discussed what they are and how they're enforced; you'll make your own decisions.

Tactical Operations

Doing a bunch of stuff with a group of people in some physical situation.

I'm (Schuyler) more here for voice instead of data comms.

4 Radio bands relevant to discussion

High freq 3-30Mhz Very High 30-300Mhz Ultra High 300Mhz-1Ghz Super high 1Ghz and up (microwave!)

All the properties of radio boil down to the frequency of your radio transmission. Always travel at the speed of light.

Longer wavelengths tend to travel farther and require bigger antennas. HF (or is medium frequency?) radio will also bounce off the ionosphere. Downside is that HF antennas have a full wavelength of ~10 meters. You wind up needing a minimum of a 6ft' antenna, which is why you don't see portable HF radios. Amazing range offset by bulky equipment. Counterexample: Citizen's Band (CB). Technically HF. Awesome, but also sucks for a different reason. (Too crowded!)

Higher frequencies:

  • Less power
  • Shorter ranges
  • Smaller equipment

Your choices further constrained by:

  • FCC regs
  • what radios you can actually obtain

All radio in USA licensed by

  • ???
  • "Licensed by rule" i.e. they say you can if you do the thing
    • Wide variety of bands that am operators are allowed to use
    • Am radio pretty inexpensive now

Once you get the license, radios are cheap and you have a lot frequency to choose from. But your name and home address go into a database, and you're obliged to use your callsign at the end of each transmission. Licenses now easy to get.


You can take a "ham cram."

  • FCC publishes 400 questions, with answers.
  • 8 hour session to prep
  • 35 questions on the actual exam, need 26 to succeed.

Don't need to know Morse code anymore.

Locations Walnut Creek Emergency Response Team SF VA Hospital etc

Users mostly older, retired. Am radio bands mostly policed by licensed users! FCC relies on these users to raise flags. Am radio operators tend to guard their bands very jealously.

Am radio operators not permitted to transmit encrypted, because you might be doing business, and business is banned. You can do packet radio over ham/am, but your packets can't be encrypted either!

Radio frequency licensed by rule

Both introduced in the 90s. Intended to mimic CB but at higher frequencies (UHF). You can buy these radios at Walgreens, Target, etc.

Differences primarily historical.

FRS - Family Radio Service

FRS restricted to 1/4Watt (1 Watt ~= 1 mile in rural, less in urban)

GMRS - General Mobile Radio Service

Licensed to operate up to 2 Watts (or maybe 5 Watts? Easy to check this.)

Used to require licensing, but not anymore. No more databases, etc. Under (5?) Watts.

Might be your best bet for your purposes. Several blocks in an urban area, farther elsewhere.

Multi-Use Radio Service (MURS)

VHF band Longer range for same amount of power Never caught on - so you can't buy them on the internet for reasonable prices.


Japanese manufacturers will let you listen on licensed, but only broadcast unlicensed. Chinese manufacturers don't care.


Update the programming on pretty much any programmable radio out there, including baofeng. Use Chirp to come up with a channel plan, program one radio, clone it, then copy it to all the other radios you need.

Use cases:

  • Use non-standard bands instead of default bands programmed into off-the-shelf radios
  • Bypass licensed, "type-accepted" bands


  • 16 channels in 400ish MHz range (GMRS and a little more)
  • Responsible citizen: use Chirp to program for GMRS
  • Super cheap, like 6 radios for $75 or about $10-15 apiece
  • Squelch tones / privacy tones
    • Doesn't give you privacy
    • Actually filters out tones you don't want
    • Like your own booth at a restaurant. Seclusion, not privacy.
  • Don't need to identify yourself, etc
  • Can't have legal encryption...
  • ...but there are opsec strategies to get plausible deniability!

No readily available consumer radio with voice encryption. (Let me know if you know otherwise!) Commercial radios (e.g. motorola) can do this, but cost ~$100 apiece. Not consumer-oriented, but maybe you can get it?

Radio Trunking

Some sort of central dispatcher assigning "virtual channels" to physical channels in physical spectrum. Physical channels actually hop around. Not really available in civilian radios.

Radio Skills

Learning how to communicate in a half-duplex channel is a skill! (Half-duplex means only one person can talk at a time.)

How does your organization develop radio use skills?

Have a dispatcher in a fixed location! Know how to clearly give your location. Train people to use brevity when speaking on the radio!

Acquire skills by practicing them! Develop exercises.