Radio nerd here. (73 y'all)
I've seen pictures of people getting arrested and one thing I've noticed is that every now and again I'll see an FRS/GMRS radio with some of these rioters.
What does that mean? Well, it means they're organized. And you can be too.
As a radio operator, when we do events and such a common thing to do is to set up a "net control" or central command or some sort of base station. This station will have high power and an effective antenna. People can then meander around with an HT (handheld radio) and communicate back to the base.
This is effective in that two HT's, which are lower power and don't have a nice antenna profile, can communicate via the base station (otherwise known as a repeater).
This can work in a couple of different ways. In repeater mode, the HT's can all communicate with the higher power repeater and it rebroadcasts and everybody hears it. Or there might be a net control operator, the HT's communicate with net control (a person) and net control responds with advice or orders or some sort of information they wouldn't otherwise have.
This radio right here is one that is inexpensive and that I've seen used by people getting arrested. https://www.amazon.com/dp/B07BXCF85T/
Knowing radio technology, I can take an educated guess and say they're using GMRS. Here's why, a nice chart that shows the overlap between FRS and GMRS frequencies: https://wiki.radioreference.com/index.php/FRS/GMRS_combined_channel_chart
You'll notice peak FRS power is 2w while GMRS peak power is 50w. If they're following legal operating power, which a lot of radios require in hardware, then that means they're operating between the frequencies of 462.5500 - 467.7250.
What does this mean and what can you do?
Well you can get a GMRS radio and antenna and listen and record. This is evidence if they're coordinating criminal activity and could help in a RICO case.
So what to do... Keep in mind this is a "line of site" radio technology, so everything's within a mile or so.
Option 1: You can spend $20 on the same radio I posted (or any GMRS radio) and set it to scan between the above frequencies. You're free to roam around.
Option 2: You can get a GMRS radio (even the HT) and use a vehicle mounted antenna. This will use the vehicle as a ground plane and have much better reception, around 3.5dBi. Example: https://www.amazon.com/dp/B00NWYVM94
Option 3: You can get a base station antenna and radio, this will have the most gain (up to 6.5dBi) with this antenna, but you're not going to be mobile. Example: https://www.amazon.com/dp/B0784FQ9VB
They're talking to each other and coordinating right under your nose, this is how you go about listening in. Record any crimes. Fuck it, give them false orders too. Don't let them own this technology, we can use it too.
They're certainly not smart enough to reprogram the radios to something else.
FYI https://gist.github.com/kennedy/11278351 PL's are listed
That channel plan programmed into a scanner with a VOX record output would be the ticket.
Other guys were chasing girls and I was fixing old radios, been at it for a long time!
VOX record on a scanner is a great idea.
I would have loved to have live throat mike audio of the fire dancers...
Wish I'd been more like you and less like the other guys.
Second best time to get started is right now.
What do you think would be a good resource to get a foundational understanding? Book?
Honestly, the best place to get into this is with a ham radio club. We do all sorts of stuff, GMRS and these other bands aren't us but it's super simple after messing with ham radio.
You can find a club here: http://www.arrl.org/find-a-club
I'd encourage you to go to the club and meet some people, get a cheap radio and listen in on your local repeater. It's really some fun stuff!
PL's won't be needed unless you are transmitting disinformation and want to be sure their radios break squelch.
If you have the right cable, Chirp can be used to reprogram these radios and remove the PL. But, I like your idea of using a scanner, or at least a radio that can be programmed to scan. I don't think the radios linked by the OP will do it.
The other radio they use is the UV-5R sold under a couple different brands such as tenway and beofang. They got in trouble because they used to be able to be modified to transmit a far more powerful signal than allowed by law using CHIRP or similar software. It's also been very popular in prepper circles for its price. We have a couple after we got a GMRS family license for when we're in the mountains skiing. The cobra or midland FRS radios just didn't have enough power usually and at $25 if someone takes a spill and it ends up damaging the radio it's not a big deal.
I thought about buying a UV-5R as a "throwaway" amateur radio handheld (I'm an Extra class ham) that I don't have to worry about damaging. I already have a digital/analog handheld that is an order of magnitude more expensive.
But, I passed after the ARRL published an article showing the results of testing for it and a few other popular handhelds. The UV-5R had the dubious honor of being the only tested radio that wasn't in compliance with FCC rules on spurious and harmonic emissions.
It wasn't an isolated instance. They bought 45 units in 2019 on the retail market, and 78% were out of spec. In 2016 and 2017, the results were even worse.
Some of those chinese handhelds can freq-hop from my understanding. Tough nut to crack.