Radio Usage for SAR

Even in 2023 with cell phone and satellite coverage, the VHF radio remains the primary communication tool for SAR missions in the field. Teams carry handheld radios and Incident Base will typically employ a vehicle-mounted “mobile” radio.

Disclaimer before we get too far: I am not a radio nerd. I know how to use it well, and I have my HAM license, but I do not spend significant amounts of free time chatting on the radio, buying new gear all the time, trying to talk to satellites with my computer through some custom programmed modem through a radio I built from scrap parts from the 1950s… as many diehard HAMs do. There are people out there that are incredibly serious about radios, and can speak far more intelligently than I can about the technical aspects of it. If you want primo technical information, talk to someone in the radio club. The purpose of this page is to give only the bare minimum information that is directly applicable to going into the field and being able to use a radio on a SAR mission.

I’ll provide a recommendation for a specific handheld VHF at the bottom of this page, but you’ll have to scroll past all of the more important content (how to actually USE the radio properly) in order to reach it. And if you scroll past it all without reading it, maybe you’ll subconsciously feel a bit guilty for not imbibing the carefully crafted content first.

While using a radio is not particularly hard, there is certainly a base level of training and etiquette to be observed. It’s similar in a way to riding a bike: it’s not very hard to learn how to do it, but if you don’t know how to ride a bike and you jump on one in the middle of a mission, you’re liable to make a huge mess of things.

And to learn it, the only way is to use it. Certainly it will help to read and digest the material written here, but no amount of book learning will make you good on the radio the first time. It’s one of those skills that develops only through practice. And you need to be willing to make mistakes. Lots of mistakes. Try, make mistakes, learn from them, modify your methods. Iterate.

Radio coms are a broadcast system. One person speaks at a time, and everyone else is forced to listen. If two people try to speak at once… FAIL. Things can get very confusing when there are a number of stations out in the field. Hence there is a system to speaking on the radio. An etiquette. Conventions.

I personally learned how to operate a radio properly while crossing the pacific ocean in a 40 ft sailboat with my wife. We had the standard VHF short-range radio that all boats carry, which we would use constantly for speaking with other boats in visible range and also back and forth with each other from ship to land with handhelds that we would take ashore with us. We also had a super long-range SSB “shortwave” ham radio. Compared to the SSB, VHF was easy. Typically, VHF would either work or not. The coms on the SSB were the hard ones, mainly due to the AM modulation (as opposed to FM which is what VHF uses). They could be quiet but clear, loud but garbled, totally clear but covered over in noise, variable from one minute to the next.

The antenna for the ssb was huge—it was the the sailboat’s backstay—the ~60 ft long steel cable that held up the mast from the aft side, and we were using wavelengths that sometimes bounce off the atmosphere. We would regularly speak to other boats that were hundreds of miles distant. Our longest com was 3500 miles, back to a HAM in California while we were most of the way to Australia. The longest open ocean passage of the trip was the stretch from Mexico to the Marquesas, colloquially termed the “puddle jump”. It took us about 30 days, without seeing another boat the entire time. Though we couldn’t see them, there were about a dozen other boats doing the same passage we were, in radio range if not sight. We would have daily radio “nets” with all the other boats for safety and socializing. The net operator’s job was to collect health & welfare checks for all of the boats, as well as coordinates for their positions. Our boat often had the best radio signal of everyone, and so the task of running the daily radio net frequently fell to me. I found the task wonderful and challenging. As the net operator, one had to juggle constant poor signals, big distances, arranging for other boats to act as relays. Occasionally, other boats would have breakdowns, or a true emergency—one boat lost all the rigging on one side of the boat, nearly dismasting, and had to limp along hundreds of miles on one tack. The entire radio net collectively tracked that sailboat across the ocean, ready to arrange emergency assistance on their behalf if they ended up losing their mast (they didn’t). The risk was genuine, and it could be nerve racking when a boat failed to check in for days at a time (usually a result of poor signal transmission rather than a real problem).

Here are the radio skills and recommendations that I think most relevant for the SAR responder.

Etiquette and Best Practices

  • It’s all about clarity and efficiency. Keep this in mind when reading the list of guidelines/rules below.
  • Be willing to get on the radio, make mistakes, learn from them, and keep making mistakes. Everyone had to go through it, even the most professional sounding person had to start from a point of awkwardness. Seriously, radio proficiency only comes with practice, so just do it. Don’t get caught in the catch-22: don’t think you need to wait to talk on the radio until you’re comfortable and capable; the only way to get there is to get started with it despite any discomfort.
  • Be very careful to not accidentally press and hold down the mic button.
    • This can happen pretty easily if one uses an external mic fastened to a shoulder strap, or shoves the radio into a pack. This ruins everything for everybody, and the only solution is for everyone to switch to a different channel (incredibly onerous and unproductive, as you can imagine).
  • Wait half a beat after pressing the mic button before you start talking
    • If you start speaking too soon, the beginning of your transmission will be clipped. This is a clear newbie tell.
    • This is even more important when going through a repeater, as it can take a bit longer to spool up and start “listening” to you.
  • Start your communication by stating who you’re calling, then your own identification. For example, if you’re Team 1 out in the field trying to call Incident Base, the order goes: “Incident Base, this is Team 1”. Then you should hear back, “Team 1, Incident Base.”
    • We do this when it is necessary, and omit it if not. It is not a fixed requirement for every communication. Efficiency, effiency, efficiency!
    • Sometimes this practice is absolutely essential so that communications don’t descend into comical chaos; sometimes it’s a flagrant waste of time. If there’s only one team in the field so that every single communication is between Incident Base and Team 1, then it’s a total waste of time to do this ID dance every time you key up the radio… so don’t bother. If there are lots of teams in the field, and multiple teams are trying to jump in on the same conversation, it becomes absolutely essential. Remember the intent, and tailor your convo accordingly.
    • There is a good reason for the order. You name the other party first, to get their attention, then you say your own name (and since you got their attention first, now they’re paying attention enough to hear who’s trying to call them). We use the “HEY YOU! …It’s me…” system. (The opposite, i.e. “It’s me… HEY YOU” doesn’t work as well).
  • Take turns. It’s a one-way broadcast, so you make a statement and then you get off the air and you wait for the person you called to respond. When you let go the mic, it’s their turn, so don’t jump back on again because you remembered something you want to add. Wait for them to respond, then when it’s your turn again, make your addition. When two people are trying to transmit at the same time, it’s called “stepping on each other” and is to be avoided.
  • Keep a pen/paper easily accessible, without having to even take off your pack.  Radio coms almost inevitably involve recording information.
  • Respond promptly when anyone calls you. If a station calls you, you should respond on your “turn” even if you’re not ready with the answer to their question or the information they need. It’s better to give a response of “we hear you, stand by while we think about what you said” than to leave them hanging with silence. If you do not respond, the assumption is that you did not receive the communication, and the calling party will try you again. There is a responsibility on the part of the receiving party to at least acknowledge the reception promptly.
  • Don’t shout into the mic, don’t stuff it into your mouth and make it sound like you’re trying to swallow it, don’t hold it inside your pocket and try to yell from three feet away. Moderation. A few inches away in a normal speaking voice is the approved textbook guidance, but really as long as you avoid the extremes you’re fine.
  • Say what you’re going to say, then get off (let go the mic). Because no one else can talk while you’re holding down the mic.
  • When you’re standing in a group and someone goes to speak on the radio, turn down your radio briefly to avoid feedback. Standing in a tight group and trying to talk on the radio is guaranteed to fail when multiple people have their radios turned up.
  • Understand the difference bewtween “yes” vs “I heard you”.
    • “I copy” or “copy that” etc means “I heard you” (it does not mean “yes I agree”)
    • Example: “Team 1; Incident Base, are you able to provide coordinates for the smoke signal in the distance?”; “IB; Team 1, we copy.”
    • Back at IB, we’re wondering what that meant. Does that mean they can provide coordinates, or just that they heard what we asked for? It is ambiguous. “We copy” isn’t really an answer to a question.
    • “Negative copy” means “I couldn’t understand you”
    • “affirmative” means “yes”
    • When in doubt, just use enough extra words to make it clear. In others words, you can just say “IB we heard your request but we can’t get a good enough fix on the smoke to provide useful coordinates.”
  • Before calling IB with a wellness check, go ahead and have your coordinates ready.  They usually want them, so save a tempo.
  • State coordinates (and all numbers for that matter) using single digits (e.g. don’t say 1900 as “nineteen-hundred” but rather “one-nine-zero-zero”).
  • Avoid using “ten” codes because SAR people aren’t expected to know them (except 10-4 that’s fine because everyone knows that).
  • If you have the phonetic alphabet memorized, wonderful, excellent work, extra credit for professionalism. If not, and you absolutely need to spell something out to be clear, just MAKE IT UP (e.g. “b” for boy, “m” for mama)
    • Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.
  • “Break” signifies that you’re switching parties (uno-style SKIP other’s turn)
    • Example: “Team 1, incident base, good copy on your coordinates; break, break team 2, team 2, incident base, please provide wellness check and coordinates.”
    • If you use this “break” technique, be ready for the second party to have tuned you out during the first part of your transmission (which didn’t concern them). It might take extra effort to get their attention.
  • This single most important aspect of good reception is line-of-sight.  I’ve used my handheld for clear coms at a distance of 30 miles, from the top of Pecos baldy to the hillside west of Los Alamos. But put a single hill between us and we can’t communicate from a quarter mile.  All other things being equal, line-of-sight makes a bigger difference to reception than anything else.  What can we do about that?  Well, often times, not a darn thing.  IB is where it is, and you are where you are.  However.  Knowing about it can still help.  For one, walking onto a small rise that may be only 5 ft higher, and holding the radio up, might make a difference.  Also, it explains why repeaters are helpful, and also how to pick a repeater.  You want a repeater that is line-of-sight to both you and to me (repeaters get their own section below). Remember: line of sight trumps all other radio considerations.
  • Always look for ways to increase efficiency. It’s all about efficiency (maybe that’s why I love it).
  • Often, simply rotating your body or holding the radio a foot away and vertical may fix marginal reception.
  • For SAR, perpetually look to eliminate an unnecessary extra back & forth each time we do check-ins.  If IB calls you for coordinates, you might be able to assume that they’re ready to copy them down (and not need to ask them every time if they’re “ready to copy coordinates?”)—depending on the IB and staff etc
  • If the reception is bad, and it’s just not working out to get your health & welfare “I’m ok and this is where I am” message through, don’t sweat it. Don’t freak out and go into stressed out emergency mode; everything will be fine. With radio coms, people understand that it doesn’t always work; Incident Base isn’t going to immediately send the helicopter for you if you can’t manage to reach them for one of the check-ins. Granted, if you just located the subject and the situation is urgent, obviously you will need to re-establish coms immediately. But short of an actual emergency situation, radio coms are going to be intermittent at times and that’s anticipated behavior.
  • Perform a proper radio check before departing Incident Base
    • Confirm BOTH transmit and receive.
    • Don’t half ass it. Don’t just say “radio check,” without ID’ing yourself, while listening to someone else’s radio, and calling it all good.
  • Always keep in mind: Just because your radio is silent doesn’t mean that no one’s communicating—you can’t always hear all sides of a convo. It is tempting to listen to SOME crystal clear traffic and assume that you’re hearing ALL the traffic.
  • Relaying. Hard to do it well; a thing of beauty when it’s done well. Here I’m referring to a manual relay, i.e. using a middle-man to pass along a message between two parties. If you have no coms with IB and you really need them immediately, you can put out a general call to see if another team can relay your message for you. Properly running the relay is a true art, but if it’s urgent then poorly done is better than not at all. If you can hear IB and you can hear Team 10 but it’s obvious they can’t hear each other, you can offer to do the relay. This is usually pretty obvious: someone is calling and nobody is answering, but you’ve been listening to both parties clearly. The challenge is knowing the correct moment to jump in an offer help. If you’re going to offer, the first thing you do is make sure you have good coms with both parties. Just because you can hear both of them doesn’t mean they can both hear you (but it’s a decent start). It might go something like this, say you’re team 5 and they’re team 10 and you start by calling them:
    • Team 10, this is Team 5
    • Team 5, Team 10
    • Team 10, Team 5, I hear you loud and clear, I’ll try to relay for you; break break Incident Base, Incident Base this is Team 5
    • Team 5, Incident Base.
    • Incident Base, Team 5, I have you loud and clear and will relay a message from Team 10; break break Team 10, this is Team 5, go ahead with your message please
    • Team 5, Team 10, our message is to tell Incident Base that we checked the small structure, found no clues
    • Team 10, Team 5, I understand your message to IB is that you checked the small structure and found no clues, is that correct
    • Team 5, Team 10, that is correct
    • thank you team 10; break break Incident Base, this is Team 5
    • Team 5, Incident Base, we copied your readback that Team 10 checked the small structure and found no clues
    • Incident Base, Team 5, that’s correct
    • thank you Team 5
    • Team 10, Team 5
    • Team 5, Team 10
    • Team 10 we passed along your message, no instructions from IB
    • Team 5, Team 10, thanks

Technical skills and knowing how to use your radio

  • Know how to change the channel on the radio
  • Know how to lock and unlock the keypad (usually just holding down the button with the key icon)
  • Know how to FIND a channel on the radio
    • Say IB asks you to change to the Tesuque repeater–do you know which channel is the Tesuque repeater?
    • Not being able to switch your radio onto a requested frequency because you don’t know how to figure out which frequency goes with which channel is an amateur hour move. To avoid this…
    • Keep a cheat-sheet with the radio. No one can memorize all the channels; carry a list so that you can correlate which channel you’re supposed to use with what’s already programmed into your radio.
  • Know how to adjust the squelch on the radio
    • bonus: know how to temporarily defeat squelch (bypass? disable?) so that you can check and adjust the volume
  • Most of the handheld radios are dual-band, VHF and UHF. Overwhelmingly we use VHF, and only occasionally resort to UHF for setting up fancy repeater systems the the field responder will likely not need to even know about. In normal radio usage you won’t even observe the difference; switching to the desired channel transparently swaps between bands when necessary. Still, it’s good to know that your radio can do both (most can). UHF is even higher frequency, so it’s even more subject to the line-of-sight limiting behavior than is VHF.
  • Know which channels programmed into your radio are the HAM frequencies, and don’t use them if you’re not licensed.
    • getting your HAM radio license is very helpful for SAR, because you can then make use of a network of repeaters located across the state. More on repeater use elsewhere. For here, know that it is illegal to use the HAM frequency bands if you don’t have your license.
  • Don’t be lured into the “more power!” fallacy. Remember: having a more powerful radio may let others hear you, but it doesn’t improve your ability to hear them… Most of the handhelds these days are 5 W, sometimes up to 8 W. But those numbers are an oversimplification, and often meaningless. A cheap 5 W radio may put out only 2 W on the desired frequency, and a stupid 3 W of noise on various harmonic frequencies (which is not only useless, but illegal). I know this from personal experience—a friend measured exactly that behavior on a Baofeng UV-5R that I subsequently threw in the trash. It’s more important to have a good antenna…
  • Advanced: know how to manually enter a frequency, offset, and a tone encoding in order to access a new repeater in the field
  • Antennas
    • Typical VHF antennas are tuned (i.e. have the right length) for 144 MHz because that’s the most common HAM band; SAR works more often in the 155 MHz band. You should definitely get a 155 Mhz tuned antenna. An antenna for 155 is slightly shorter than for 144.
    • Holding the antenna close to your body results in some radio energy being absorbed by your body and less getting out. Holding it away from your body may buy you a bit of reception. I know I mentioned above in the etiquette section to speak from a few inches and don’t shout at the radio, so this is different guidance, but try it if you need to
    • Antenna shape can be used to redistribute the radiated power in one direction at the expense of another—this is called GAIN. Higher gain antennas can help get better transmission and reception—as long as you’re pointing the antenna in the right direction. For a whip or telescoping antenna, the “right direction” is normal to the antenna axis.  Think of a disc—lower gain the disc is fatter and doesn’t reach as far; higher gain the disc is narrower and reaches farther. This means you should keep the antenna vertical, so your transmit “disc” remains parallel with the earth.
    • Carry a second, telescoping high-gain antenna. If you have trouble with reception, you can swap antennas. The telescoping antenna is unwieldy and not practical for bushwhacking, but can make the difference between having coms or not. The other nice thing about the telescoping antenna is that you can by a 144 MHz one and then shorten it just the right amount to properly tune it for 155 Mhz frequency. If you know a nerdy radio type, they will have a SWR meter that you can use, and you can shorten the antenna to just the right length and then mark it for the future.

License and Legality

In SAR, we use SAR-specific frequencies in the vicinity of 155 MHz, and we use HAM frequencies in the vicinity of 144 MHz. Being in SAR does not grant you legal right to use HAM frequencies—you must get your HAM license to do that. Being a HAM does not grant you legal right to use SAR frequencies—you must be participating in a SAR mission to do that.

Also, one can only legally transmit on the 155 Mhz frequencies with a Part-90 certified radio. A Part-90 radio has to satisfy tighter specifications for transmission quality than a $20 junk radio off Amazon can pull off. You should be using a Part-90 certified radio for SAR. Note, there is a difference between “compliant” and “certified”. “Certified” means it’s been tested and passed; “compliant” means that it ought to pass the test to obtain certification, if it were ever actually tested.

The Part 90 radio will likely not be permitted to access the HAM frequencies when you first take it out of the box. That doesn’t mean it is incapable of using them, only that by default they assume the operator is not likely to be legal on those frequencies, so the capability is disabled. If you also have you HAM license, then you will need to go into the radio programming and enable the HAM frequencies. This may be as simple as programming the radio with the HAM frequencies and it just works, or it may be that the radio is locked down so hard you can’t manage to open it up to HAM frequencies. Caveat Emptor.

Ham Repeaters

Let’s talk about HAM repeaters.  First of all, you can’t use them unless you have your HAM license. Being able to use the repeaters on SAR missions is the best reason to get your HAM license.

In this section I’m referring only to third-party repeaters, other people have set them up, they’re semi-permanent, usually on towers, that kind.  We also have a different sort of portable repeater that we can deploy on missions, but that works differently and I’ll write about that elsewhere.

I don’t want to get too complicated because that will not help you to be more effective with SAR radio coms.  Suffice to say a repeater is a fixed radio apparatus that re-transmits a signal.  Think of a weatherproof box on a radio tower in the middle of nowhere, hopefully in a high place that we can all see (line-of-sight).  It acts as a middle-man for radio coms.  It does not receive and retransmit on the same frequency; it doesn’t work that way, it’s not that simple.  The repeater receives on one frequency, and re-transmits on a different frequency.  So the handheld radio needs to be specially set up so that it transmits on the right frequency to the repeater, and then receives on a different frequency from the repeater. 

There is an important implication to this.  If I am standing right next to you and I am set to a repeater frequency, in order for you to hear me, BOTH of us need to be in range of the repeater.  It’s not like it goes direct to each other when we’re close, and only uses the repeater to increase the range when we’re far from each other.  When we’re using the frequency that is set to the repeater, everything goes through the repeater or you don’t hear it.  Now, there’s a fancy way to swap around the frequencies so that you’re bypassing the repeater and “going direct”, but that requires a different channel, different transmit and receive frequency settings and is beyond the scope of the material here..

Next little repeater tidbit.  The repeater uses a sort of lock/key setup to restrict access.  In order for the repeater to listen to your transmission, your radio needs to include the proper “key” so to speak (really it is a “tone” in a DTCS or CTCS digital/continuous tone coded squelch).  Whatever, point is, the radio has to be set up to send the right tone for the repeater to function. Sometimes there is also the vice versa lock/key: the repeater may do the favor of transmitting a certain “key” to unlock your radio, and your radio is typically set up (though it doesn’t need to be) to ignore any signal unless that key is received. 

You will want the repeater settings programmed into your radio ahead of time. It is too much of a hassle and takes too long to try to do that out in the field, when you ought to be starting the searching.

Practically speaking, using a repeater is pretty straightforward.  Mainly, you need to give it extra time at the beginning of your transmission in order to “key up” the repeater. Other than that, there are HAM rules about identifying yourself, which you will learn when you become a HAM.

After you get some experience using repeaters, you’ll learn to recognize when your transmission is so weak that the repeater does not “break squelch”.  In other words, it’s ignoring you because your signal is too weak.

Sometimes our settings are simply wrong for the repeater.  Maybe we can transmit but aren’t receiving, or vice versa.  It happens.  Things change, programming might have a mistake in it, we definitely haven’t tested every single channel on the new brigade radios.  When this happens, basically it’s an “oh well” moment that we can’t usually fix in the field, we just note it and try to remedy it before the next mission. 

Gear

There are many, many handheld VHF radios that will work. I hesitate to even mention a particular brand or model, because how you use the radio is the most important thing here, not which radio you possess. That said, some visitors to this page will be looking for a gear recommendation, so let me provide some non-zero response…

For a handheld, as I write this in late 2023, a fair number of responders seem to be enthused about the Anytone AT-D878. We see teams adopting these for their standard-issue radio. This is the radio I would recommend, if compelled to choose one.

I have a Wouxun KG-UV9T(plus) handheld which doesn’t seem to be available anymore. That radio has always worked great. However, I think the quality is highly variable, not only between Wouxun models but even different radios of exactly the same model. I have heard of broken antennas, random transmit circuit faults, etc. I consider myself lucky to have one that seems perfectly serviceable. The Wouxun radios will probably work out fine, but it’s less of a sure thing.

I’ll say it again: the antenna is as important as the radio. For goodness sake get one that is tuned to the SAR frequencies rather than the HAM frequencies. Often the handheld will ship with a 144 MHz antenna and you want a 155 MHz one.

For a vehicle mobile radio I have the Wouxun KG-UV920P. It’s perfectly fine so far. I’m not in love with it, but there’s no problem with it. I like the detachable head unit, with a speaker on the microphone. I relocate the head unit onto a folding table outside the vehicle, and the audio comes out of the speaker right there on the mic (otherwise the relocatable head unit isn’t much use, when the audio is coming out of a speaker buried under my passenger seat).

Two other FCs have recently installed an Anytone mobile unit, which has a wireless (via Bluetooth) microphone that is even more portable than the relocatable head unit that I have. But I’m not sure how well the bluetooth mic works—I’m still waiting for those radios to see enough action with which to build an informed review.

Matt Holmes, 12/1/23

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