Why scan?

By Jock Elliott, KB2GOM

A while back, Thomas, SWLing’s Maximum Leader, told me the scope of the SWLing Post is “shortwave listening first, then all things radio.”

As a fan of “all things radio,” when conditions on the shortwave and HF ham bands are awful, frequently I will turn on a scanner (or two) to monitor local VHF and UHF communications.

So why scan? Here are a few of my reasons.

First, scanning increases my enjoyment of communications monitoring in general. Communications monitoring is about hearing stuff, and the more I hear, the better it is. Depending upon current events and/or changes in location, I alter the types of communications services that I scan. For example, when I visited Sodus, NY, I monitored maritime frequencies to hear the activity on Lake Ontario. At another location, I might monitor the local air traffic controllers. When an ice storm passed through the area, I monitored first responders.

Second, “content DXing.” The content that can be heard on scanners is, on occasion, astonishing. Without doubt, I hear things on a scanner that I can hear nowhere else. To name just a few:

  • planes (airport air traffic control and VHF inflight communications),
  • trains (yes, railroads use radios),
  • automobiles (where I live State Police communicate on unencrypted analog frequencies);
  • fire and emergency first responders;
  • police (if not encrypted);
  • VHF and UHF ham bands,
  • business communications.

When confronted with all the different kinds of difficulty in which people can find themselves (particularly on the first responder frequencies), I find myself giving thanks for how nicely undramatic my life usually is.

Third, monitoring public service communications – fire, police, and emergency first responders –  increases my awareness of what’s going locally and that, in turn, can be useful in avoiding trouble spots or traffic problems.

Forth, scanner listening can be opportunity to pray for folks who are in trouble. About a month ago, I was monitoring fire and EMS frequencies when I heard a transmission from an ambulance to a local hospital: “We are inbound with a 14-month-old male found unresponsive in his bed, performing CPR, attempting to establish airway.” Heartbreaking.

If you think you might be interested in a scanner (and I have no commercial interest with any scanner company or retailer), the type of scanner that you will need depends on the sophistication of the communication systems in your area and the kinds of communications that you want to hear.

If you are in the United States, I recommend consulting the Radio Reference database click on the NEAR ME button and follow the prompts. The database will show you what communications are available in your area and what communications systems are involved. If, for example, the database indicates the local Sheriff frequencies are “Project 25 Phase 1,” you will need a scanner capable of receiving P25 Phase 1 communications. If, however, the local Fire and EMS frequencies are labeled FM or FMN, the most basic level of scanner will be capable of hearing those communications. If the Radio Reference database indicates that some of your local communications services are encrypted, you won’t be able to hear encrypted communications with any scanner.

If you find this all a bit confusing, there are retailers who specialize in scanners, and they can help you figure out what you need, and, if necessary, pre-program a scanner for you. (Again, I have no commercial affiliation.)

Finally, there is a fifth reason why I scan: public service. I use four scanners routinely as part of the Commuter Assistance Network. One scanner monitors the local VHF NY State Police frequencies; another is locked onto the UHF frequencies used by the NY State Police on the New York State Thruway; a third scanner sweeps through three national emergency frequencies and a couple of regional interoperability frequencies, and the fourth scanner monitors first responder frequencies for Rensselaer County here in New York State.

In the end, perhaps scanning can open the door to increased enjoyment of your communications monitoring and “all things radio.”

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25 thoughts on “Why scan?

  1. Roger Fitzharris

    Another way to satisfy that scanner itch, for Android users, is to download the Scanner Radio App and listen to “live” audio from “scanned frequencies” from the US and around the world.
    Someone else (a volunteer) uses their scanner and their computer to send their scanner’s audio to Broadcastify.com’s servers. [This is done by connecting one end of an audio cable to the earphone jack of the scanner radio; and, then, connecting the other end to the computer’s Line-In or Mic-In port.]
    In other words, when you’re using the Scanner Radio App to listen; you’re hearing the audio that’s being relayed to your smartphone or tablet by Broadcastify.com (which includes: Wunderground.com, RailRoadRadio.net, etc). The result is live audio from: police/fire scanners, marine, rail, and air (scanned) frequencies, amateur radio repeaters, weather radios, etc.
    This approach allows you to scan, by proxy, many of those VHF/UHF communications that you listed in your post without the hassle and expense of purchasing a scanner and programming it. I realize for some this approach would not be as satisfying as the real McCoy. However, it has allowed me to monitor some really interesting conversations: an air-to-ground transmission during the August Complex fire in CA (2020) from the pilot of a flame-retardant tanker as he crested a ridge getting the final drop zone instructions from the fire fighters on the ground below – I could almost smell the smoke. Another example, you mentioned trains, how about a RR engineer to dispatch reporting a car on the tracks somewhere in the middle of Indiana around midnight. The car was abandoned, and the train was going nowhere. The decision was that a special rail car (I’m assuming one with a winch) would have to be sent to the scene in order to left the car off the rails. The last I heard the dispatcher was trying to find lodging to put the two-man up for the remainder of the night. Those two examples certainly lend credence to your supposition that the content that can be heard on scanners (or scanner app, in my case) can be, on occasion, astonishing.

  2. Franz Miller

    I agree, scanning can be a wealth of information. My little Kenwood TH-F6A handy talkie has several modes of scan fuction and since it covers all modes from 0.5MhZ to 1300MhZ there’s always something interesting. I even use it to familiarize myself with the correct way to communicate with ATC (Air Traffic Control) since I play X-Plane & DCS (Digital Combat Simulator) computer video flight simulation; both have an ATC feature included in their programming. This is just one of many uses, besides casual listening!
    Franz Miller

  3. john

    Currently listening to my SDS200 (I also own the handheld unit little brother of the SDS100).

    The Uniden SDS scanners are the only scanners available that can deal with simulcast issues that plague radio systems with multiple transmission sites.

    There’s always something interesting going on where I’m located. In the last few days I’ve monitored cops dealing with a shooting and pursuing the suspect and searching for the spent cartridges. Also a search and rescue mission where they were just about to call in the Trooper Search and Rescue helicopters just before the individual was found.

    If you’re interested in scanning the following website has tons of information on scanning, the frequencies and public radio systems etc:


  4. Andrew (grayhat)

    Well, Jock, I do that routinely, I mean sweeping through different bands and then (I use SDR for that), if I see an interesting signal, tuning it in and trying to “fathom” it; in many cases such stuff can be received/read w/o any special stuff, in other cases one may need some kind of decoder, I’m not going to post links about those (software stuff) also since they may be illegal (in some or all countries), I’ll just give a pointer to a useful “signal identification” software named “artemis”


    which, I think, may be pretty useful at times 😉


    any news about the external antennas idea

    1. Jock Elliott


      I have not yet caught the SDR but your comments intrigue me . . .

      I will check out that link.

      The outdoor antenna project will be delayed until spring, when the thermal window coverings come off.

      As I write this, it is snowing!

      Cheers, Jock

  5. Rob W4ZNG

    Making lemonade out of lemons, here in FL, law enforcement has gone over to SLERS, which is unscannable by any commercial unit. That’s OK though, there’s lots else out there to listen in on:

    – Hospital dispatch: This was great information when waves of covid swept through the county. The numbers of covid calls per day gave an approximate early warning when things were heating up again. Also, hospital calls can let me know when Florida Man is active in the area.

    – Fire dispatch: Much the same as hospital dispatch. Good to know what’s going on.

    – Ham 2m & 70cm calling frequencies: I keep the scanner in my home office, and this lets me know when to run to the shack and call back.

    – Marine VHF calling frequency: Lots of boat chatter, some of it interesting.

    – CB: Usually too much skip garbage to be worthwhile, but it’s nice to listen in during deer season.

    – FRS/GMRS: It’s fun to listen in on the occasional tourist comments as they mill around downtown. Also, there’s a nearby boatyard that has some interesting chatter. Finally, when there are climbers working on the telecom tower about a half-mile away the conversations can be lively, such as when last year some climbers decided it would be better to defer some work to when osprey nesting season was over.

  6. Peter L

    Radio is radio and it’s all fun. I understand the Boss’s mantra of “SW first” because, you know, it’s his site. 🙂 But he does include “all things radio” and that’s good because if you limit yourself to one radio sub-hobby, you are absolutely missing out on other stuff you are interested in if you gave it a try.

    Technology in VHF/UHF monitoring has changed a bunch since I bought an *Electra* Bearcat BC100 programmable hand-held in 1982 but if you want to listen, the technology is available.

    Public safety comms, particularly law enforcement, are where the problems lie. Any kind of “scrambling” on a radio system used to be an expensive add-on; with APCO P25 and other modern digital systems, it’s a button-push. And the people attracted to some services are the same people who think that no one should ever know what they are doing because Criminals Might Hear Details (it’s a variation of “if we allow you to take pictures the terrorists will have won” mentality). Locally, and likely because the cops control the system, even most of the fireground channels in the FD’s radio zone are encrypted. *Fireground*. EMS to emergency department? Nope, in the clear. It’s one of those problems that’s not technical, but management/political.

    And it’s not “scrambled”, it’s encrypted meaning that you *will* *not* *be* *able* *to* *decode* *it*.

    As someone who has had scanners for 40 years, I can assure you that 99.9% (possibly 99.99 … or 99.999) of law enforcement radio communications are entirely routine and, if heard by “Criminals”, would be of no use to them.

    All that said, plenty to listen to that is still analog. Not only is aircraft radio, both civilian and military, still analog, but it’s AM. Railroads (well, the AAR) have settled on NXDN for digital. Not sure how many places are actually using that as most RR comms are on the same ~95 numbered VHF FM channels they’ve been on since the 1960s. Maritime radio, even under GMDSS, is mostly VHF FM, at least in “Sea Area A1”. There are software decoders for the digital selective call stuff even (I believe it’s the same protocol at VHF as it is ag MF/HF).

    One other point … a lot of the VHF spectrum assigned to “Land Mobile” radio is now unused, especially on “low band”. Some of it, in the area of Public Safety, is because comms have been moved to county-wide, regional, or even statewide trunked system, usually on 700/800 MHz. Others, like local deliveries taxis, etc, just use cellphones now – no need to buy a radio system if all your workers have phones. I’ve never seen any organized effort to re-use that now-fallow spectrum. There are some Part 5 Experimental operations run by amateurs hoping for a world-wide 40 MHz (the 8 meter band) allocation, but that doesn’t have much traction yet. It makes the whole Narrow-banding effort of a decade ago seem silly – we really didn’t need all those new channels because few of the old channels were in use outside the largest metros. Sold a lot of new radios, though.

    1. mangosman

      North America.
      If the Low band to which you refer is from 47 – 50, 54 – 74.8, 75.2 – 88 MHz includes TV channels 2 – 6 which has been virtually deserted by digital TV then it will cover 359 DRM channels of 100 kHz each. Another 198 DRM channels are available if FM and HD radio in the FM band was switched off. Currently this is 98 FM channels (for interference free HD radio it would be half that), in the Medium Frequency band there is 116 overlapping AM channels.
      Thus there is plenty of channels available for Digital Radio Mondiale broadcasting. Each channel can carry upto 3 sound channels and a data channel.
      If all radio broadcasts were to move into this frequency band, the AM/FM divide will disappear and it will be up to the broadcasters as to what sound quality and type of content they broadcast.

      Peter, I have been trying to find the manufacturers of new low band VHF transceivers and have not been able to find any online. I have checked the FCC for TV transmitters on channels 2 – 6 and there are hardly any on air in digital. Analog has been switched off. This still leaves 50 – 54 MHz 6 metre amateur band which is also used in the rest of the world except Europe/Africa.

  7. Bill Hemphill

    As usual Jock, another very nice write up. I always enjoy reading your posts.

    While I’m not big fan on scanning, I have to admit I occasionally fall back to it when I get bored.

    This past year, I found out that several of the local amateur operators had placed GMRS (General Mobile Radio Service) repeaters on the air. So I loaded all the GMRS frequencies (which also includes the Family Radio Service) into my Yaesu VX-6r radio. Hooked it to an outdoor antenna and then just let it scan all day to see what I might hear. While I did hear the GMRS repeaters and the occasional FRS signal, I kept hearing an unusual signal on one of the FRS channels. Since I was only getting bits of it, I preceded to just listen to that channel.

    Turned out it was the local elementary school. They were using FRS radios to keep track of how many kids were on the playground. There would be a transmission stating “20 children with three teachers leaving for playground”. Then every so often one of the teachers would report “20 children three adults on playground”. Then a transmission “20 children and three adults coming back in”. Finally “20 children with three adults back in classroom”. I found it very reassuring that they were using radios for up-to-date tracking of the kids. There were plenty of other transmissions from the school also.

    But I wondered – did the school buy the radios or did one of the teachers or administrators just decided to pick a few up at the local store and put them to use. Either way, it demonstrates a creative use of radios. Especially cheap FRS radios.

    Another time, I was listening to the aircraft band when I heard a pilot declaring an emergency on board with sick person, requesting an ambulance to be available upon landing. The signal faded before I got the full story.

    And a few years ago I was listening to the aircraft band and heard an air-air chat between two pilots. They had just released a group of skydivers and were returning back to the small local airport. Great chat between them on their family, events, plans for the weekend, etc.

    73 Bill WD9EQD
    Smithville, NJ

    1. john

      The public schools radio communication are part of the public safety digital system where I live.

      Listening to the the bus drivers coordinating with the dispatchers getting the students to school and back home is like monitoring a military operation in full swing with all the attendent student shenanigans that occur daily.

      The local schools, public and private, also use individual radios to monitor activity within the schools to keep an eye on the students, e.g. at one local school the other day there was a bumped head at recess, one student throwing up requiring a clean-up and a fight in the 7th grade boys hallway. Every day is a new adventure!

    1. Jock Elliott


      That is an SDS 200, and it is one of those scanners that is database-driven (it comes with a memory card that contains all the active frequencies on the Radio Reference database) . . . you simply put in your zip code or longitude and latitude, select the services that you want to monitor, and the scanner does the rest . . . no programming necessary. It’s very, very slick, and very, very expensive, but I am glad I bought one. (and I get no rewards for saying that.)

      The SDS 200 comes with a whip antenna, but I highly recommend connecting it to one of these — https://wiki.radioreference.com/index.php/Homebrewed_Off-Center_Fed_Dipole . I built the wire version for just a few dollars, hung it in a corner of the radio shack, and it works very well.

      Have you been good this year? Maybe Santa . . .

      Cheers, Jock

    2. john

      Concur with Jock.

      I own the SDS100/200 scanners and they’re the best scanners available. Very sophisticated pieces of high-tech.

      The SDS Uniden scanners are the only radios on the consumer market that can handle silmulcast problems in areas where there are multiple transmission sites. This issue can prevent reception of digital signals on other scanners.

  8. Robert Gulley

    Excellent reasons for enjoying the scanner, Jock! I would add an addition thought for encouragement to try scanning – many are worried about encryption and digital comms on a scanner. It can be intimidating, and I am no expert with it. However, there is so much more to scanning than just police and fire, even if those are encrypted. Local services such as busses, snow removal (timely!), marine, Coast Guard, aircraft, National Guard, towing services, cabs, hospitals, etc. There is far more unencrypted than one might realize, and if you are fortunate, even much of the police and fire might be unencrypted in your area.
    Besides, you can always start with an analog scanner and work your way up – analog scanners can often be had for a song on used sites, or even free from local radio folks. It’s a lot of fun!
    Oh, and one other thing I have listened to is one of our local TV stations broadcasting a director’s cut, so to speak – the reporters talk but so do the engineers / technicians giving behind-the-scene directions. Very cool!

    1. Jock Elliott

      Well, said, Robert! All good points.

      Analog scanners are a great place to start. I used two of them when I am running the Commuter Assistance Net.

      Cheers, Jock

    2. john

      I’m fortunate where I am, almost nothing is encrypted, including police. For some reason only the local dispatch channel for police is encrypted. However, that dispatch channel is cross-patched into the local military base’s radio system and it’s not encrypted there.

  9. Frank K4FMH

    Great post, Jock. While I know using rtl dongles and other SDRs (which I have in spades) is all the rage for scanning right now, I still maintain a scanner in my shack. Radio Reference is well worth the donation…especially with software like ProScan which can query and retrieve RR directly.




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