australia:navigation
navigation management for hikers
Introduction
getting lost in the Australian bush is a major risk - everything tends to look the same and usually there is no mobile internet to help you when you most need it
it is important to have a map and compass as well as smartphone or GPS, and recovery options such as carrying an EPIRB and to inform others of destination and expected return time prior to departure
Using a compass and map
how high is a mountain using an inclinometer on your compass?
take a measurement of the angle to the peak of the mountain from where you are, let this angle be alpha
walk z metres towards the mountain and take a second measurement of the angle to the peak and let this angle be beta
height in metres = z x tan alpha x tan beta / (tan beta - tan alpha)
compasses
most compasses are optimised for the hemisphere in which you will be to make it easier to adjust for magnetic north
some compasses are global and can be used anywhere in the world
compasses can lose magnetism or reverse polarity if stored close to a microwave device (EPIRB, smartphone) or magnetic material such as Apple iPhone MagSafe, etc
compasses become inaccurate if used near other compasses, magnets, batteries, metallic objects, etc
most compasses with glow in the dark markings are phosphorescent and require initial light then last for some 4 hours, some military grade compasses use radioactive material and do not need to be primed by light and will glow continuously for around 7 years
some compasses have an adjustment screw to manage magnetic declination map error, others you need to adjust manually
some compasses are marked in 360 degrees and some are marked in the more precise 6400 mils (milliradians) which is what is used in the military for artillery purposes
some compasses are “lensatic” which means they use a magnifying glass set at 45deg angle to the compass to more accurately line up a bearing line
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lensatic military compasses
the tritium versions of thee are generally the best compasses for night time use
these are used VERY differently to base plate or mirror compasses
Cammenga Lensatic Tritium USGI Compass
compasses with mirror sightings
other high quality compasses
Using a smartphone
bring a compass and topographic map as backup as well as an EPIRB especially if you are going out of internet range
ensure you download maps for the area BEFORE going there as internet access is probably NOT available
turn off WiFi and BlueTooth to conserve battery power
ensure you take a USB power pack as your smartphone battery will not last long with GPS running
UHF CB Radios
NOT useful for emergency communications due to limited coverage
generally not worth carrying while hiking, except for group management purposes
they are popular with 4WD convoys and for groups of hunters
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Consider taking a satellite communicator
Take a personal EPIRB radio beacon
this device has ONE JOB only - to send a continuous radio distress signal if you activate it
battery lasts around 2 years usually
they need to be registered with the local radio beacon service
the main downside is they will not activate if you fall off a cliff !
australia/navigation.txt · Last modified: 2021/11/01 22:55 by gary1