Emergency whistle for bushwalking

[Rico]

Yesterday someone asked a very unusual question about the Vargo titanium emergency whistle:

"how loud is this whistle, compared to the two-chamber discordant lifejacket whistle(>500m audible range)?"

I like to give proper answers, but in this case I had to apologize and explain that I didn't have any official data about it.
This was his follow up:

"i once used a 7.62x39mm rifle shell as a whistle.. dad heard it easily at >750m range(god it was loud,left my ears ringing for 2 minutes)
perhaps it would pay to do some testing, and advertise results.(if it really is as loud as you say)
judging from the volume and diameter of the titanium whistle, it will be a lower pitch than the shell i used"

at this point I felt the challenge and I explained that:
"I cannot just check if I can hear the whistle at 500m, as the environmental noise, the wind direction, any natural barrier and even the altitude can dramatically change the result. For example the sound will go further in a valley than in a flat area, and trees may reduce the strength of the sound. We may measure the decibels, but I don't think that people would understand how noise it is if I say it is 80db or 100db. The only solution I found so far is to measure the decibel and to do a noise comparison. For example: "this whistle is 90db, as noise as a Boeing 737 before landing". This may work. What do you think?"

and this is the email I got this morning:
"aha, science, just what i need to start the day,....here are my thoughts, hope it helps: i'm not sure, but i think air temp and pressure only affect the speed of sound, not how far.
there is a third factor in how far sound travels.....why is the sky blue?..... FREQUENCY. Red sound waves will be heard for miles(viz the call of the Brown Bittern), I know from flute making that low frequencies need a high volume , too large for awhistle,unless you double the length back on its self
red noises will be directional, unlike blue noise which will be hard to locate in a forest(ie, high frequencies scatter)
open ended whistles (recorder/tin whistle) are an octave higher than closed end whistles,
so much for the science of noise, now for the crucial part,,,, HUMANS
we hear something discordant far more easily than a pure note. a dischordant note means there more than one frequency
this doesnt necessarily mean 2chambers. as in [a life jacket approved whistle] which i would put at 140db, blown at full bore
a .22hornet shell is the best for a small compact whistle, but you gotta blow full bore.
7.62*39mm shell comes a close second, lower pitch, but it will wake the dead
a hydro electric power station running at 100HZ(50hz is only half the audible frequency), 120dB is audible for 5km(in the valley on a calm day)"

After this email I asked him if we could make the discussion public as it is getting really interesting, and he authorized me to publish it on this forum. He also concluded saying:
"ok, sounds good, i have found the marine whistles the best for a pre- manufactured whistle, but nothing i have come across yet can rival a 22hornet shell, or a 7.62*38mm shell for a whistle. refferee's whistles arent very loud at all."

I like my whistle much better than a plastic lifejacket one. I use one of them as keyring, and another is attached to my belt when I go hiking so I know that even if I live my pack in the tent and I go for a short walk, I always have the whistle with me. They really are one of the most important and easy to carry safety device. But I'd love to know if a modified 22 hornet shell can really generate such a powerful sound, anyone with experience in the field?

[corvus]

G'day Rico ,
Interesting thread ,when I was taking my Scouts Hiking /Bushwalking they all had to wear a whistle around their necks (even in bed ) funny thing is now, my adult son and I still carry whistles but on or in our main packs rendering them useless when we leave them to do side trips so perhaps we should revert to the old rule (around the neck at all times)
As to quality and volume of sound I still use my old Police style one and my son's is a cheap "survival" type one both of which sound very loud but never have been tested in the field so I guess we will need to do a review of sorts when next on the track and report back
corvus

[Strider]

I have two whistles. One built into the striker of my fire steel, and the other built into the sternum strap clip on my pack. Hadn't given it a thought, but neither go with me on side trips!

[Ent]

Hi

I pack PLB, first aid kit (which has the whistle in it) and rain gear along with toilet stuff in the day pack (and now small headlamp after a longer than planned peak bagging side trip) so where ever I go the "vital" stuff is with me. To keep the weight down and size I use one of the orange emergency whistle. It claims to be mega loud but honestly a good old fashion umpires whistle sounds louder. Like the PLB I have never used it in anger. Been tempted to try it in the bush just to see how it would work but this does not feel right in case someone thinks my testing is a real emergency. When on Hanson Peak I heard whistles down on the track that goes around it. Turns out some people being stupid. Amazing the distance the sound carries in open country when you are up high.

Cheers

[corvus]

Re reading your post Rico does that imply that blowing over the top of those bullet cases can reproduce the required effect or have they been crafted into whistles ? sorry also cannot understand the technical details such as you need to blow full bore because I believe if you want any whistle to achieve its highest decibel you will need to give it your best.

I am also of the firm belief that the old "police style " is still very loud however the cheap plastic ones are catching up fast.
corvus

[Bluegum Mic]

Sadly I can tell you mine is nice and loud as my toddler picked it up in the store and gave it his best blow next to a lady with a migraine (hence why we now own this lovely green new whistle I always carry my whistle, suncream and small knife on a carabiner which is on my shoulder strap opposite side to my SPOT. I simply change it to whichever pack Im about to carry along with my medical kit.

[sthughes]

The sternum strap whistles really aren't very loud, I also carry another which has a thrmometer (now busted) and compass built in. But that still isn't as good as my "Thunderer" footy umpire's whistle which I seem to have misplaced in recent times. Interesting idea re the bullet cases, I remember trying that with some .22 casings and it was *&%$#! loud, expecially 2 at a time! Definitley an UL option.

[michael_p]

A friend of mine used his soccer referee whistle. It was the loudest whistle I ever heard and you did not want to be standing next to him when he blew it.

[Nuts]

Watch the ears, if they are loud enough they're too loud for eardrums. I did see a comment somewhere about the advantage of forward blasting over top outlet whistles. I'v'e tried a few different designs. Something to keep in mind is ease of use. Some need to be blown at the right pressure and angle (which may be hard to get in any sort of panic).

[tasadam]

This gets me thinking. I own a sound pressure level meter, measures decibels. I could craft up a frequency generator and portable amp, then a bunch of us could meet up at an outdoor / bush setting, with our whistles and earplugs and do a sound-off.
Whistle levels at 1 metre and say 5 or 10 metres (outside, on a still day). Then perceived volume at a given distance, say 100 metres (which sounded loudest). Everyone gets a scoresheet & records what they think.
Also get the signal generator hooked up and play set frequencies to see if we can detect which frequency sounds loudest.
I could also hook up a microphone head to an oscilloscope and measure the frequencies of the whistles tested on the day, though it might be easier to record the sound & measure it on the computer.
From that, we should be able to establish whether there is much difference between different whistles, and also which whistles are more suited to the purpose for which we might need them.

There's the idea. Any refinements? Any takers? And perhaps members of the forum that think they have the best whistle can send it via post for the test...

[Ent]

Hi Tasadam

Sounds over the top but hey is not most gear reviews. I am game. The important thing is sound carry and for that frequency and even the "warble" might make the difference.

A lot if gear gets sold with extravagant claims. Also as Nuts points out, a whistle that takes out your hearing means less chance to hear a reply.

Actually has anyone used one in a real world situation?

Cheers

[sthughes]

Sounds like fun Adam! Most of that can be done with an iPhone you know? But the microphone isn't much good for the close up decibel ratings as it tops out to early.

A whistle you can blow hands free is advantageous so you can use your hands to block your ears!

Actually has anyone used one in a real world situation?

I've used one that time we lost Corvus and Pomysi up in the Walls. They didn't hear it (either my loud one or sternum strap one). There was no line of site and probably 1km to 1.5km apart as it turns out. UHF might have been more useful.

[Rico]

Hi Corvus

Re reading your post Rico does that imply that blowing over the top of those bullet cases can reproduce the required effect or have they been crafted into whistles ? sorry also cannot understand the technical details such as you need to blow full bore because I believe if you want any whistle to achieve its highest decibel you will need to give it your best.

my customer sent me an email quoting directly your question:
"yes, the harder you blow the louder it gets, if you want to be heard, give it your best shot, you arent whispering to a kitten
yes, you do have to blow over the muzzle of the shell
the following common shells need to be cut down to blow across their larger diameter, and to right length to work as a survival whistle: 222, 223, 243, 22-250, 270, 270mag, 300mag, 303, 30-06
22 hornet , 32 pistol shell, 38, 7.62*39(ak) need no modification to be an effective survival whistle

to put it on a key ring, i replace the spent primer with a machined brass rod(tight press fit, hammered home) and drill a small hole across the brass rod now protruding from the shell, to fit a #7 fishing split ring, and cut off excess brass rod.. use the second smallest drill in your 13 piece set, and take it slow, there isnt much room for error drilling this hole. i use a slow drill chuck, and my leatherman pliers to machine down the brass rod
you do not need a licence to buy un-primed brass, the brass is in good condition , and it costs about $1/shell
do not drill any holes in the resonating chamber, this will ruin the sound.
needless to say, DO NOT USE LIVE AMMO TO CUT UP!"
"for those who dont know, a decibel represents a 26% increase in the noise level,
which derives from the 10th root of 10, so 101 decibels is way louder than 100dB
there is a simple way of testing, get the two whistles side by side, and see which one can be heard the furthest(needs a remote patch of desert, so as not to cause panic)"

I kindly asked him to join directly the conversation, as I am sure we'd love to ask him some more question about this DIY whistle.
Rico

[corvus]

Thanks for that information Rico
corvus

[Rico]

This gets me thinking. I own a sound pressure level meter, measures decibels. I could craft up a frequency generator and portable amp, then a bunch of us could meet up at an outdoor / bush setting, with our whistles and earplugs and do a sound-off.
Whistle levels at 1 metre and say 5 or 10 metres (outside, on a still day). Then perceived volume at a given distance, say 100 metres (which sounded loudest). Everyone gets a scoresheet & records what they think.
Also get the signal generator hooked up and play set frequencies to see if we can detect which frequency sounds loudest.
I could also hook up a microphone head to an oscilloscope and measure the frequencies of the whistles tested on the day, though it might be easier to record the sound & measure it on the computer.
From that, we should be able to establish whether there is much difference between different whistles, and also which whistles are more suited to the purpose for which we might need them.

There's the idea. Any refinements? Any takers? And perhaps members of the forum that think they have the best whistle can send it via post for the test...

I love the idea! I am willing to send one of my whistles over. Lets define what features we need in an emergency whistle specifically designed for bushwalking.
- Of course as loud as possible
- As small as possible. The marine whistles are usually double chamber, but it is too bulky for a bushwalking whistle. I think we pretty much agree that it should be always on your person, even when answering the call of nature at night!
- made of plastic or of a material that does not rust. If we wear it around the neck it will be in contact with our body sweat (an acid), or if we wear it on our belt as I do it will be exposed to the weather.
- No moving parts as it may get dusty or muddy if the emergency is due to a fall

The important thing is sound carry and for that frequency and even the "warble" might make the difference.

Good point! High frequencies are directional, very easy to understand where the sound come from, lower frequencies may propagate better if the sound come from a crevasse or an area with dense vegetation.

a whistle that takes out your hearing means less chance to hear a reply

True, another excellent point. So the whistle should have a rear exit, or as Sthughes pointed out, it should be "hand free" so you can block your ears with your hands.

This is getting fun, I had a look in Internet and I couldn't find any proper bushwalking whistle review.

Rico

[Falco desertum]

Adam here, aka Desert Falcon
high frequencies tend not to propagate very far in a forest, at close range they are directional
low frequencies carry for miles(viz fog horn)
i had a go at a scout/umpires whistle, with /without warble, loud(<400m) , but not loud compared to the marine safety discordant dual chamber lifejacket whistles at full bore
the lifejacket whistle i have around my neck is black, but identical to the orange ones you can find on ebay. you certainly need to hold your ears with this one.(this one is DESIGNED to be heard above a raging Bass Strait storm at sea, easily heard >500m on land against a moderate wind).
as such, a marine safety whistle should be the standard by which all other whistles are tested
I havnt got a chance to test the vargo titanium whistle which started this discussion.
the 22hornet can be heard easily at approx 1km on a noisy day, loud enough to alert my slightly deaf father, left my ears ringing
22long rifle casings are loud, but the pitch is too high
22magnum are the smallest for an effective survival whistle,


I have used my marine safety whistle many times to call out to my bush walking family in morse code
re:iPhone, great, untill the batteries are dead... toss!

[Rico]

Hi Adam, thanks a lot for publicly joining the conversation we started in private.

as such, a marine safety whistle should be the standard by which all other whistles are tested

I agree with you, they are designed for emergency use and they need to be approved for use with emergency floating devices, so they can be use as standard to evaluate other whistles. But as you said a high frequencies tend not to propagate very far in a forest, and it may not be the best sound for bushwalking use. I'd love to see a test involving one of your shells

[ramgrabber]

you mean just by blowing across the case mouth? i tried it with a 5.56×45 (223) and for me 90% of the time it sounds like as if I've left the window ajar on a windy night but 10% of the time I can get a proper 'whistle' sound. But not yet comparable in loudness with normal whistles
will chop one down as he(Falco?) suggests so the whole shell is the same diameter (i.e. so new length is about 35mm) and report back later
but I can't say I've had a problem with the loudness of my other whistles ('Fox' style ones and one integrated into the sternum strap from a backpack as someone else also mentioned) so it seems a bit too much trouble than it's worth unless we are talking ridiculously loud. will have to try and see

[Strider]

you mean just by blowing across the case mouth? i tried it with a 5.56×45 (223) and for me 90% of the time it sounds like as if I've left the window ajar on a windy night but 10% of the time I can get a proper 'whistle' sound. But not yet comparable in loudness with normal whistles
will chop one down as he(Falco?) suggests so the whole shell is the same diameter (i.e. so new length is about 35mm) and report back later
but I can't say I've had a problem with the loudness of my other whistles ('Fox' style ones and one integrated into the sternum strap from a backpack as someone else also mentioned) so it seems a bit too much trouble than it's worth unless we are talking ridiculously loud. will have to try and see

This might be of interest...

http://www.instructables.com/id/223-Survival-Whistle/

[tasadam]

This might be of interest...

http://www.instructables.com/id/223-Survival-Whistle/

Brilliant!
Doubt it could be done by the wditten instructions, but a pic tells a lot of words!

[Falco desertum]

you are right, it dose sound like antarctic wind unless you chop a 223 down to the same length as a 38, and blow across the hole like a normal shell
the same goes for 222, 224, 243, 270 etc

th e only ones that dont need modification are 22hornet, 32auto, and ak shells
thanks for the link, will try. he was using a 22lr. the same could be done with 243 and 22mag. 22-250 and 22lr should also work, with different pitch
i have yet to find the right shells to do the same trick with 270, and 300, and 303, anyone who knows, please inform us all

Falco

[Falco desertum]

This might be of interest...

http://www.instructables.com/id/223-Survival-Whistle/

Brilliant!
Doubt it could be done by the wditten instructions, but a pic tells a lot of words!

just tried a 243 and a 22mag
just like the vid, except no soldering needed, using a light hammer and 5mm core, carefully flatten the rim off a .22long rifle, this needs to fit easily down the tube of the 243, once this fits easily, you can fit the 22lr into the 22mag, this will bring it to the right diameter to fit solidly into the 243. now file half the lid off the 22lr, to look like the vid, and file the rim off the 22mag, so you can blow through. then insert into the 243 with wedge cut out, as per vid. drill the primer out to 5.5mm, and tap an M6 thread. and drill a transverse 2mm hole into the shank of a stainless M6 bolt, cut to thread to length.
this is much louder than 223, but you have to recess the jet 4-5mm from the cut to get best effect
if 22mag slips too easily into the 243, you can crimp the muzzle of the 243, with a drill chuck, and crimp the 22mag at cross purposes, then press to fit, this will be a tight fit, enough to stay in place

[Strider]

Looking at getting a proper whistle. Does anyone have experience with the Fox 40 Sharx or Fox 40 Sonik Blast?

[sailfish]

and this is the email I got this morning:
"aha, science, just what i need to start the day,....here are my thoughts, hope it helps: i'm not sure, but i think air temp and pressure only affect the speed of sound, not how far.

Pressure does not affect the speed of sound, that is a function of the velocity of the vibrating molecules which is a function of temperature. Outdoors the speed of sound appears to vary with altitude only because of the temperature gradient. At a constant indoor temp it does not vary. Had this come up on a flute making forum, really thrashed it out as it related to tuning. I was unconvinced until studying a NASSA standard atmosphere chart for an altitude region where temp and speed of sound are constant while pressure changes. So its true by theory and in practice.

I found an interesting comment about playing concerts in the Andes, that it is hard to get wind instruments to penetrate far but the traditional pan flutes (siku) are most effective in thin atmosphere. Closed tube whistles like these are much more effective with a constricted opening and wider closed end (bottle shape). In other words a brass shell case.

Be aware that while low frequencies travel long distances with little dispersion, they give less indication of direction while high frequencies give much better direction, they scatter more so in forest will not be heard far at all. Probably the reasoning behind dual tone emergency whistles.


Regards,
Ken

[Burnsy]

Interesting read, did the field test ever happen?

I want to buy a coupe of good whistles for my two kids to keep around their necks. the Vargo Titatium look good with a lanyard already attached as do the Fox 40 Micro's. I think the plastic micros would be my choice if they are both equal in ease of use and volume.

Has anyone used these and more importantly had their kids use them? I don't think I need to worry about looking for a whistle that will cover huge distances at this stage as I think my kids would be lucky to get more than 100 metres away from us before knowing they were lost. We have in the past always told them to stop and yell, don't keep moving but a whistle would be heaps better.

[thejungleisneutral]

I carry a Fox 40 Micro in my personal survival kit, which, when I'm carrying a conventional backpack, is an off-the-shelf Doug Ritter/AMK Pocket Survival Pak - fits in the pocket of the hiking pants. I've tested the Fox 40 Micro a few times, but have never had the cause to use one in anger.

Brian Green in the US ran a comparison between the various distress whistle types commonly found in his neck of the woods. - http://briangreen.net/2011/03/safety-wh ... sting.html

The results were a little surprising.

[Burnsy]

Thanks for the link. I am no expert but would think that a 0.4 decibel difference over the ones he tested is statistically insignificant in a field test. I think the second arguably less scientific test someone in the comments section made is probably a better measure of emergency whistle effectiveness however he did not include the Fox 40 micro unfortunately

[stry]

As well as the Fox40, there is an English company called ACME which makes dog whistles, police whistles, and all sorts of interesting stuff.

Their plastic signal whistle is very effective.

[keithy]

Thanks for the link.

Burnsy - another link you might find handy is http://bigpigblog.com/tag/whistle-test/

Again, not tested in real world scenario, but he goes through a wide range of whistles. I have a few of the ones he reviews (Fox Sharx, Promo, sternum, SOL slim, zipper pull, and an ITW Fastex lifejacket whistle).

BTW Simon's Tier Gear has the ITW pretty cheap http://www.tiergear.com.au/11/online-sh ... tle-Orange

[Bubbalouie]

For giggles here: http://youtu.be/I9QuO09z-SI

On a more serious note, I've heard that pips can freeze or fail in certain circumstances. I also read that some metal whistles can have problems with extreme environments as they use non-metal resonators causing differential expansion/contraction problems (not sure about this one though, seems like a stretch). Probably not a big concern for kids as they'll not be going to those sorts of places.

In any case, the point is, as I understand it a whistle should be made from a single material and have no moving parts (a pip for example) in order to maximise reliability.

(EDIT: forgot to mention, have a Nitecore NSW10, it's ear drum burstingly loud, haven't tested audible range in any meaningful way though, it appears to have a plastic resonator)