It monitored various emergency and other radio channels used by police, fire department, ambulance service, taxis and so on. The '10 channels' is in reference to how many tuned channels the thing can scan.

Here is some more detail for that particular scanner:

https://www.rigpix.com/rs-realistic/realistic_pro57.htm

Waiting for someone to explain that iPhone has replaced this too (via streaming), completely unaware that the origin of the stream is likely a 3.5mm jack on... an actual scanner.

While very true, so long as someone keeps that scanner online and the source remains unencrypted, only one person needs to own a scanner rather than hundreds.

Sadly, my city now encrypts all police channels. Fire and EMS can still be streamed though.

I am surprised they such sensitive channels are not encrypted. Both for confidentiality and integrity.

It depends on the region and specific needs, but a common reason for not encrypting is that it adds complexity in an emergency (where, e.g., people might need to communicate from other regions nearby, or ambulance needs to talk to fire, maybe civil defence or AREC needs to be involved.) The simplicity of plain unencrypted radio can outweigh the benefits of secrecy.

This said, different places weigh factors differently, there's no one-size-fits-all answer.

But then you lose accountability.

In what sense?

Likely replaced by group text for most. my grandpa drove snowplow for the state and often had the scanner listening for when he might be called in. he couldn't respond directly but he did call dispatch to give his ability to come in. Pagers probably replaced that for many.

It might be possible to use iPhone as scanner with RTL-SDR dongle. I don't know if there is any scanner software for the iPhone, most of it is PC software.

Anything is possible with accesories but that breaks the thesis.

For the moment, yes. But in practice, this years dongles are next years built-ins. The same was the case with GPS, accelerometers, temp and humidity sensors, blood oxygen sensors, incident light detection, finger print reading, cameras and so on. Phones absorb sensors like toddlers consume cookies, they can't get enough of them.

I want to those things. Tricorder please.

It will happen. The bigger obstacle is to make sensors cheaper. But MEMS has opened many doors already and I think microfluidics and various gas sensors (think chromatograph in your pocket) will be the next frontier.

I wish that Apple would match all these sensor features on their laptops as well.

I’d like to have a thermometer in my iPhone, for ambient temp, but most of all I am waiting for IR photography and the the inevitable calibrated fever thermometer app.

I'll bet $20 you can find a combination thermometer cellphone on aliexpress.

Oh, I found one already!

I don’t want an Aliexpress phone, though.

The promo image for the next Apple event looks kinda like IR false colour to me, so maybe you’ll get your wish?

I have this absurd vision of someone sticking their smartphone edge-on into a slab of beef as a meat thermometer.

SDR++ app enables this on Android

Ah, I remember those now! I forgot they were called scanners. Thanks!

I used to sell that particular model (I worked for Tandy on Saturdays in Amsterdam when I was a kid).

Radio frequency scanners are far from obsolete overall but they typically have a lot more channels and scan much faster now. They have continued to evolve or devolve for those that like simplicity. Plenty of people, myself included still have scanners in their home and vehicle. I just had mine on to find out why a parade of ambulance, fire and troopers were going down the highway.

Semi-related because Radio Shack, a store manager taught me how to leverage my "Tandy Service Plan" to get free upgrades on my scanner for life. I was not ready for him to do this. He grabbed my handheld 20 channel scanner by the antenna and smashed it on the desk. Then he handed me a 200 channel scanner because Radio Shack no longer had an equivalent model. Once the 200 channel scanner was obsolete I got a free 1000 channel scanner. Each iteration scanned both channels and stepped frequencies faster. Most scanners lock out particular frequency ranges but this can be bypassed usually by cutting one diode or moving a jumper. Radio Shack preferred the diode method. Nowadays people call this "frequency expansion" or expanded on scanners, ham radio, etc... Some HAM radios can be used as scanners once frequency expanded.

Some now prefer software defined radios to double as scanners. I like both. SDR's are great at home but too much clutter for in the vehicle for me. SDR's combined with leaked keys can monitor P25 encrypted law enforcement tactical channels.

Right, but more specifically they are most often used for scanning stuff like air-band and VHF/UHF two-way radio traffic. Nowadays with a lot of public safety being digital P25 (requiring more expensive scanners) and online streams being so easily available, there's not a lot of reasons to buy a scanner unless you're really passionate about it.

I used a scanner this weekend to listen to the Blue Angels perform. It was also helpful to have their ground crew frequencies in their so we knew that they were a few minutes out from taking off (we watched from a few miles away at a friend’s house with a good view). Scanners are far from obsolete!