53 votes
Accepted

How do you aim a signal mirror?

How I've practiced is I hold my left hand palm out, and I create a "V" between my ring and middle fingers with the plane or person between my fingers. I then hold the mirror by my face and shine the ...
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  • 590
26 votes

How do you aim a signal mirror?

A modern (Korean War era and later, at least) signal mirror has a hole in the center, and the hole is surrounded by a grid of retroreflectors. You aim the mirror spot at something close by, then look ...
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23 votes
Accepted

What are the consequences of — illegally — using a 446 MHz PMR in the North American wilderness?

In both the U.S. and Canada, amateur radio operators serve an important role in providing emergency radio communications during war, disaster, terrorist attack, or whatever other emergency. So amateur ...
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20 votes

What is the risk of starting a forest or wildland fire with a flare gun?

There is a definitely a risk of starting a fire with a flare gun, for this reason they are discouraged by the National Park Service (at least in Grand Canyon-Parashant National Monument). Not Useful: ...
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19 votes

How do you aim a signal mirror?

This answer applies only to signal mirrors which are two-sided and have an aiming hole in the middle, which should be the case with any good signal mirror. My answer will partially duplicate a prior, ...
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  • 5,158
18 votes
Accepted

How do you wave off a search and rescue helicopter?

Charles Brumbaugh's answer is correct if a helicopter rescue is underway and you need to warn an approaching helicopter that it should abort the approach due to some problem you have spotted. (From ...
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  • 5,862
15 votes

How do you aim a signal mirror?

Your signal mirror is likely polished on both sides, with a hole in the middle to help you aim it. Although the principle is simple, it's fiddly and takes a little practice. With the mirror in ...
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  • 4,348
11 votes
Accepted

Are there standard whistle signals for communicating with separated party members?

From Scouting For Girls, Official Handbook of the Girl Scouts Whistle Signals One blast, "Attention"; "Assemble" (if scattered). Two short blasts, "All right." Four ...
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11 votes
Accepted

Garmin inReach vs. overcast sky

Iridium uses radio frequencies around 1.6 GHz or 18.75cm wavelength. Atmospheric absorption at these frequencies is very low: Clouds contain water droplets, though. So, let's have a look at rain ...
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  • 226
9 votes
Accepted

Are there standardized signals to communicate with aircraft?

International standard and very easy to remember is the Y or N signal. If you want to communicate more than that, your signals should be easy and self-explaining. If you are e.g. climbing and it's ...
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  • 12.1k
8 votes

How do you wave off a search and rescue helicopter?

There used to be an article on the homepage of the Austrian mountain rescue service concerning behaviour during helicopter rescues, originally published in Berg und Steigen 3/02 (a professional ...
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  • 1,239
6 votes

How do you aim a signal mirror?

The sun isn't a laser, so you don't actually have to be very accurate. The further away your target is, the less accurate you have to be as the reflection will spread.
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6 votes
Accepted

Is there a safer way to use a flare in a wooded area?

I would say that the alternatives in the the answers to the linked question would be a better idea, but if you had to use a flare then there are a couple of things that could lessen but not eliminate ...
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6 votes

What is the risk of starting a forest or wildland fire with a flare gun?

Flares ignite at 191 °C (376 °F) and burn as hot as 1,600 °C (2,900 °F). This makes them incredibly dangerous since they are well above the ignition temperature of most flammables found in a forest or ...
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  • 161
5 votes

What are the consequences of — illegally — using a 446 MHz PMR in the North American wilderness?

I am an amateur radio operator (Extra Class) active in Skywarn. Yes, PMR radios transmit in the amateur radio spectrum in Canada and the U.S. Yes, it is not legal. In the wilderness, far away from ...
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5 votes

Are there sound-based alternatives to whistle signals for group communication?

I'm sure this isn't what you were shooting for but using radios, satellite phones, cell phones, etc. would all count because they transmit the "noise" of your voice to your target where it is ...
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  • 9,608
5 votes

What would happen if I use a USA (GMRS/FRS) two-way radio in Europe?

Personal radio devices in Europe use a different frequency (446 Mhz). According to a quick google search the frequency range of GMRS/FRS (462-467 Mhz) is used by fire brigades in UK, police in Russia ...
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5 votes

Are there standard whistle signals for communicating with separated party members?

Beyond the previously mentioned Scouting communication guidelines, Morse Code is definitely an option. However, Morse code isn't as widely known anymore and could potentially be misinterpreted as a ...
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  • 430
5 votes

Are there sound-based alternatives to whistle signals for group communication?

Percussion Drums have been used historically to communicate over long distances in forested areas, so you could send messages simply by knocking on wood. Pick up a couple of hard sticks, and knock ...
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  • 53k
4 votes

Can you use an Iridium phone with a SIM but with no active plan to place an emergency call?

I looked at some different plans and it looks like you could buy a prepaid plan and not activate it for up to 2 years. See the pricing here. However that seems like the really expensive option. ...
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4 votes

Are there sound-based alternatives to whistle signals for group communication?

I spent a summer with two brothers from the Dominican Republic and they would call out to each other with a loud howl-like "FOOOOOOOOOOOO" sound that carried very well through fields, forests, and ...
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  • 3,921
4 votes

Are there standard whistle signals for communicating with separated party members?

If anyone has hiked in the woods knows that noise may not travel very far, especially in dense forested areas. So the use of any whistle would imply that group members should be relatively close ...
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  • 9,534
4 votes

Garmin inReach vs. overcast sky

I have an inReach and have used it in all sorts of conditions and terrain. Overcast weather is not a problem but a reflective tarp or deep canyons can be. If a message fails to get through the device ...
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4 votes
Accepted

Do Garmin InReach plans include unlimited incoming messages?

Incoming messages count against the limit of text messages. Yes, any message sent back to your inReach device, including replies to preset messages, count against your monthly message allotment. ...
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3 votes

Are there standard whistle signals for communicating with separated party members?

The nice thing about standards is that you have so many to choose from. - Andrew S. Tanenbaum While there are standards you and your companions need to know and agree upon what that standard is prior ...
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  • 1,327
3 votes

How can I report an emergency via SMS text message?

Although the question specified using no equipment beyond a standard mobile phone, I think it's worth pointing out that VHF and UHF radio signals can typically be heard over greater distances than a ...
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  • 404
3 votes

How can I report an emergency via SMS text message?

In the EU (including the UK), SMS to the general emergency number (112) appears to be widely supported technically, but several countries I checked appear to require pre-registration. It's not clear ...
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  • 404
3 votes

What qualities to look for in a good emergency whistle?

... what qualities ...? immediate availability to the user not liable to cause injury to the user - cold, sharp edges, hearing, lanyard strangulation etc. health of the user - lung capacity, breath ...
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3 votes

Are there standardized signals to communicate with aircraft?

Two arms up (Y) indicates you are in distress. One arm up, one arm down, indicates that you are not in distress. Also, when in distress, our friends in Europe tend to recognize the rule of 3 ( or 6 ):...
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