So I was told to start looking into these as a prepper.  I had a few thoughts and questions if you guys could give me the 411

Assume all cell, internet  and phone lines are down.

1) In HI, where everything is so close, what's the purpose?  I mean I can understand non urban areas on the mainland because if you need help or supplies, you can coordinate with others of like mind.  That's if they're willing to help/barter.  But with HI being such a small place, I don't understand this concept.  Due to our size, hunkering down would be #1. Then if need be, to move to the predetermined locations.  I mean I guess 1 could radio a friend who has a radio as well, but this isn't the mainland where you're 100 miles away.  1 could walk to their friends place if they really needed to.  But then again, you're bound to run into a red cross type center along the route.  So why not just go there for supplies/help.

1 example I can think of is when we had the earthquake and all phone lines were down. I used Myspace messenger to msg my gf at the time.  So can this radio be used to call 911 for help if the phone lines are down?   I think if this is possible, then it would be a good reason to get a CB.  I'm going to assume HPD and like frequencies are encrypted, so there would have to be a main channel for help.

2) Tin foil-invasion.  In the history of the modern USA, an invasion has never happened.  The closest would have been on 12/7/41.  So the likeliness of using a CB for this is minimal and closer to zero.  But then again, to coordinate with our military, they will have comms to distribute. And if you're going to be part of the militia, then again, comms will be already there to distribute. I could understand more if 1 had a farm close to the border where illegals cross and LEO are hours away and bad stuff happens.  But then why would this persons phone lines be down where they cannot call, text, email their friends for help until LEO shows up.  I mean guess 1 could prep for Murphy's law where the power and lines are out.  But also why would an illegal stay to fight once they hear self defense gunfire is another question.

3) Far more close to zero chance of using is like the Bundy Ranch situation.  A fellow is being illegally targeted by the feds and his friends come to help.  How many here would actually show up ready to fight? Especially since Oahu is mostly urban.

Please don't take any of the above as an insult.  I am trying to understand the need.  I mean at $40 for a set of 2 on Amazon, I might just buy them cause they're cheap.  I would not broadcast, so no license would be applied for.  And if I do have to broadcast, then that means SHTF and who cares about a license.  I could be wrong about this part and the law as well.  So fill me in if I am. 

Best argument I know of, as it was in the beginning of the CB craze of the 70's, is you have a standard that everyone can participate in. 

There are a fixed number of channels -- 40 channels between 26.965 MHz and 27.405 MHz. -- , everyone is able to find/use those channels, and the equipment could be as cheap ($20) or expensive as you can afford.  There are handheld, mobile and fixed station radio setups.

I think the simplicity and affordability for a standard communications platform is what has kept it relevant. 

There are also no licensing requirements.  Anyone of any age can legally operate a CB radio, with a few exceptions such as foreign government agencies.

Citizens Band Radio -- the name pretty much says it all.

The FCC does have rules on what is allowed and not allowed.  These rules are intended to keep the system from being monopolized or interfered with.

https://www.ecfr.gov/search?search%5Bdate%5D=current&search%5Bquery%5D=CB+Radio&view=standard

Many, if not most, of the FCC rules govern the Citizens Band Radio Service (CBRS), which is defined as:

A mobile and fixed two-way voice communication service for facilitating personal,
business or voluntary public service activities, including communications to provide
assistance to highway travelers.

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-D/section-95.903

It's good to know when you broadcast on channel 9, there's a system set up to monitor your call for emergency services.

    Used to use when driving  truck in mainland.
Lot of us also had in our cars with big A$$ whip antennae's.
Many locals here have it on their boats.

   Short and sweet of it
Cheap
no age limit
no license required.
Channel 9 is the "Monitored " Channel initially monitored by REACT International, Inc. (Public Service Through Communications)
" It differs from the other cb radio frequencies in that it transceives on a rotating cycle of each frequency in every 10-second interval.
So when you are tuned to channel 9, you will hear all the other channels for one second each rotation (a complete spectrum sweep)."
Channel 11 is   rarely used due to its proximity to an  ham radio repeater output frequency channel 1.
Guess that could be good or bad.

   Biggest downside is the 3 mile or so range.
If I remember correctly, you can only max out at 4 watts.
Been awhile.

[snippy-hi-yay]

   Biggest downside is the 3 mile or so range.
If I remember correctly, you can only max out at 4 watts.
Been awhile.

Good memory!  I knew range was limited, but I could have only guessed at that value.

Transmitter power is limited to 4 watts in the US and the EU.

CB radios have a range of about 3 miles (4.8 km) to 20 miles (32 km) depending on
terrain, for line of sight communication; however, various radio propagation conditions
may intermittently allow communication over much greater distances.

https://en.wikipedia.org/wiki/Citizens_band_radio

Had a CB in my first car. Very handy communication tool pre cell phone era. Used to communicate with my pops when he was out fishing on his boat. Clear line of sight is much further than 4 miles. Hills and buildings will block range definitely.

Had a big antenna on my car though lol

Had a CB in my first car. Very handy communication tool pre cell phone era. Used to communicate with my pops when he was out fishing on his boat. Clear line of sight is much further than 4 miles. Hills and buildings will block range definitely.

Had a big antenna on my car though lol

Yeah, all the cool kids had the giant "State Trooper" style whip antenna.  My brother must have gone through half a dozen shorty antennas looking for one that worked best.  Eventually he went with the 6 ft whip.

If I remember, the top end of the whip was in a clip mounted on his door frame so he could reach up & out the window to disconnect it for maximum height when needed.

High tech!!   

Yeah, all the cool kids had the giant "State Trooper" style whip antenna.  My brother must have gone through half a dozen shorty antennas looking for one that worked best.  Eventually he went with the 6 ft whip.

If I remember, the top end of the whip was in a clip mounted on his door frame so he could reach up & out the window to disconnect it for maximum height when needed.

High tech!!   

In my daze, that whip was a weapon. 

IMHO, CB is of pretty limited usefulness on Oahu.  Terrain and buildings, low max power, and no repeaters really limit what you can do.

I got an amateur radio license during COVID, 90% because I was bored and electronics interest me, and 10% because society might collapse and I’d want to be able to communicate with home base as I made my way back, Walking Dead-style.    Decent number of repeaters on island, with pretty good coverage. 

You kind of have to define your use case.  Amateur (HAM) radio has some emergency services organizations like ARES, if you’re interested in being part of the solution rather than just another victim in a disaster.  In a no-kidding, rule-of-law-has-collapsed situation, you sort of need to have a predetermined group of properly equipped people to communicate with.  On the bright side, nobody’s going to be checking your license in that case…