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Blue Mountains (Katoomba)
Blue Mountains (Katoomba)
27Mhz (AM) CB frequency table
Australia has two main types of CB or Citizen Band radio. This articles lists the channels and frequencies used by the AM or 27MHz type. This is the cheapest type of CB available and used for long distance communications.
Channel | Freq (MHz) | Use |
1 | 26.965 | |
2 | 26.975 | |
3 | 26.985 | |
4 | 27.005 | |
5 | 27.015 | |
6 | 27.025 | |
7 | 27.035 | |
8 | 27.055 | Road contact |
9 | 27.065 | Emergency Calling only |
10 | 27.075 | |
11 | 27.085 | General Call (IE contact then find another channel) |
12 | 27.105 | |
13 | 27.115 | |
14 | 27.125 | |
15 | 27.135 | |
16 | 27.155 | General call for Side Band (LSB) |
17 | 27.165 | |
18 | 27.175 | |
19 | 27.185 | |
20 | 27.205 | |
21 | 27.215 | |
22 | 27.225 | |
23 | 27.245 | |
24 | 27.235 | |
25 | 27.255 | |
26 | 27.265 | |
27 | 27.275 | |
28 | 27.285 | |
29 | 27.295 | |
30 | 27.305 | |
31 | 27.315 | |
32 | 27.325 | |
33 | 27.335 | |
34 | 27.345 | |
35 | 27.355 | |
36 | 27.365 | |
37 | 27.375 | |
38 | 27.385 | |
39 | 27.395 | |
40 | 27.405 | |
470Mhz (FM) CB frequency table
This article lists the channel, use and frequency table for the 470 MHz FM CB radio for Australia. These radios are becoming very common in the outdoors. Cheap handed held radios that operate over 1-2km are available for less than $100 at many electronic shops. These types of CB radios give access to a large network of freely accessible repeaters throughout Australia. The use of these repeaters can extend the range of communications up 50km. Includes links to lists of all UHF CB repeaters in Australia
UHF CB repeaters NSW
UHF CB repeaters VIC
UHF CB repeaters TAS
UHF CB repeaters SA
UHF CB repeaters WA
UHF CB repeaters QLD
UHF CB repeaters ACT
UHF CB repeaters NT
Channel | Freq (MHz) | Use |
1 | 476.425 | Repeater access (In Duplex mode) |
2 | 476.450 | Repeater access (In Duplex mode) |
3 | 476.475 | Repeater access (In Duplex mode) |
4 | 476.500 | Repeater access (In Duplex mode) |
5 | 476.525 | Emergency Call channel (simplex or duplex) |
6 | 476.550 | Repeater access (In Duplex mode) |
7 | 476.575 | Repeater access (In Duplex mode) |
8 | 476.600 | Repeater access (In Duplex mode) |
9 | 476.625 | |
10 | 476.650 | |
11 | 476.675 | Call channel |
12 | 476.700 | |
13 | 476.725 | |
14 | 476.750 | |
15 | 476.775 | |
16 | 476.800 | |
17 | 476.825 | |
18 | 476.850 | |
19 | 476.875 | |
20 | 476.900 | |
21 | 476.925 | |
22 | 476.950 | Telemetry and Remote control (ie no talking) |
23 | 476.975 | Telemetry and Remote control (ie no talking) |
24 | 477.000 | |
25 | 477.025 | |
26 | 477.050 | |
27 | 477.075 | |
28 | 477.100 | |
29 | 477.125 | |
30 | 477.150 | |
31 | 477.175 | (Outgoing channel for duplex repeater access) |
32 | 477.200 | (Outgoing channel for duplex repeater access) |
33 | 477.225 | (Outgoing channel for duplex repeater access) |
34 | 477.250 | (Outgoing channel for duplex repeater access) |
35 | 477.275 | (Outgoing channel for duplex repeater access -Emergency) |
36 | 477.300 | (Outgoing channel for duplex repeater access) |
37 | 477.325 | (Outgoing channel for duplex repeater access) |
38 | 477.350 | (Outgoing channel for duplex repeater access) |
39 | 477.375 | |
40 | 477.400 | Road channel |
Points of a compass (Cardinal, degree)
There are 4 basic directional indicators used; North South East and West. I assume this is not news to you. A compass uses the same principles and breaks directions down even further to allow more accurate descriptions. When needing to be very accurate you will talk in degrees when general is ok then you will talk in cardinal directions (eg when describing wind direction or the general direction of a track.)
Below you will find two diagrams and a table.
The cardinal points diagram shows a basic compass bevel and the cardinal points
The compass bevel diagram show the mix of cardinal points and degrees that are common on a compass
The Bearing and cardinal points table relates the angle in degrees to a cardinal point and the text descriptor.
- Cardinal Points
- Compass Bevel
- Bearing and Cardinal points table
Degrees | Cardinal Point | Spoken (lazy) | ||
0.00 | N | North | ||
11.25 | N by E | North by east | ||
22.50 | NNE | North north east (Nor nor east) | ||
33.75 | NE by N | North east by north | ||
45.00 | NE | North east (nor east) | ||
56.25 | NE by E | North east by east | ||
67.50 | ENE | East north east | ||
78.75 | E by N | East by north | ||
90.00 | E | East | ||
101.25 | E by S | East by south | ||
112.50 | ESE | East south east | ||
123.75 | SE by E | South east by east | ||
135.00 | SE | South east | ||
146.25 | SE by S | South east by south | ||
157.50 | SSE | South south east (sou sou east) | ||
168.75 | S by E | South by east | ||
180.00 | S | South | ||
191.25 | S by W | South by west | ||
202.50 | SSW | South south west (sou sou west) | ||
213.75 | SW by S | South west by south | ||
225.00 | SW | South west | ||
236.25 | SW by W | South west by west | ||
247.50 | WSW | West south west | ||
258.75 | W by S | West by south | ||
270.00 | W | West | ||
281.25 | W by N | West by north | ||
292.50 | WNW | West north west | ||
303.75 | NW by W | North west by west | ||
315.00 | NW | North west (nor west) | ||
326.25 | NW by N | North west by north | ||
337.50 | NNW | North north west (nor nor west) | ||
348.75 | N by W | North by west | ||
360.00 | N | North |
Track Classification System
An Australian standard for bush track was developed in 2001 in consultation with a number of out door bodies and organisations. These Standards are used to describe the condition of the track and the terrain and give a feel for the level of experience required by people using them.
The following tables gives a bit of a feel for the tack classification standards. I have modified them a bit from the AS 2156.1-2001 to suit the need of the website. As well as these elements for classifying a track the standard does also outline guides for management, these include facilities to provide, publicity and intervention levels.
The pictures in this table act a a bit of a guide, but only refer to the specific element been studied (IE just the sign or gradient)
A walk is then classified based on the higest class number found.
In this table below you will see the range of assessments made for a particular track ranged the full gamut but generally sat around class 3. But because the one element of weather ranged from 1 to 4 then this walk will be ranked a 4. However if in the summer months the weather class never extends beyond 3, then you could class this was as a 3 in summer and 4 in other seasons.
Standard Class | ||||||
Elements | 1 | 2 | 3 | 4 | 5 | 6 |
Track Conditions | ||||||
Gradiant | ||||||
Signage | ||||||
Infrastructure | ||||||
Terrain | ||||||
Weather |
Please see the AS 2156.1-2001 standard for more information.
Naismith’s Rule (estimate walking time)
Naismith’s rule was developed by a William Naismith in 1892 as a basic rule of thumb that can be used to calculate the time it will take to walk from point a to b. The formula has been adapted a little since then and considers the distance to walk, the altitude changed and the speed that you will walk at.
This rule assumes a reasonable level of fitness, but Tranter’s corrections can but used to change the time to suit a particular level of fitness.
Naismith’s Rule first makes a calculation based on distance over time. eg if your walking a 4km/h for 4 km it will take you one hour. Not rocket science. But it adds a bit over an hour and a half for every 1000m you climb and about three quarters of a hour for every 500 meters you descend.
I have include two methods to help you in your trip planning. Firstly a calculator and secondly a Nomogram that you can use with a ruler in the field. Have a play with both
- Naismith’s Rule Calculator
- Naismith’s Rule Nomogram
- How to use Naismith’s Rule Nomogram
This Nomogram below can be used to calculate the estimated walking time.
At first this Nomogram can be a bit overwhelming to look at. But don’t stress I think you will pick it up quickly.
First you need to pick an altitude shift line.
Move from right to left to find the line that represents the number of meters you will climb in total, next
Move down the number of meters you will descend in total.
Follow this new line up and to the left (this is your altitude shift line)
see here we plan to climb 700m and descend 1000m
Next we keep going up the altitude shift line until we get to your estimated walking speed.
This is our pivot point.
In this example it is 4km/h
Now just draw a straight line from the number of Kilometers you plan to walk, through the pivot point till you hit the Hours axis. And voila you can read the estimated time.
In this example we will walk 10km and the answer is 4 and a half hours
If you wish to apply Tranter’s Corrections I have include a table below to help.
Fitness in the left column is the number of minutes that it would take you to climb 1000ft over 800m
f i t n e s s (m) |
Time taken in hours using Naismith’s Rule | ||||||||||||||||
2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | ||
15 (fit) | 1 | 1½ | 2 | 2¾ | 3½ | 4½ | 5½ | 6¾ | 7¾ | 10 | 12½ | 14½ | 17 | 19½ | 22 | 24 | |
20 | 1¼ | 2¼ | 3¼ | 4½ | 5½ | 6½ | 7¾ | 8¾ | 10 | 12½ | 15 | 17½ | 20 | 23 | |||
25 | 1½ | 3 | 4¼ | 5½ | 7 | 8½ | 10 | 11½ | 13¼ | 15 | 17½ | ||||||
30 | 2 | 3½ | 5 | 6¾ | 8½ | 10½ | 12½ | 14½ | |||||||||
40 | 2¾ | 4¼ | 5¾ | 7½ | 9½ | 11½ | |||||||||||
50 (unfit) | 3¼ | 4¾ | 6½ | 8½ |
Heat Index
You have heard it said that “It’s not the heat, it’s the humidity” Well, actually it’s both. Our bodies dissipate heat by varying the rate and depth of blood circulation, by losing water through the skin and sweat glands, and, as the last extremity is reached, by panting. As the body heats up, the heart begins to pump more blood, blood vessels to accommodate the increased flow, and the tiny capillaries in the upper layers of skin are put into operation.
The body’s blood is circulated closer to the skin’s surface, and excess heat drains off into the cooler atmosphere by one or a combination of three ways…
- radiation,
- convection, and
- evaporation.
At lower temperatures, radiation and convection are efficient methods of removing heat. However, once the air temperature reaches 35°C, heat loss by radiation and convection ceases. It is at this point that heat loss by sweating becomes all-important. But sweating, by itself, does nothing to cool the body, unless the water is removed by evaporation (sweat changing to water vapor). The downside of this method of cooling is that high relative humidity retards evaporation.
Relative humidity is a measure of the amount of water vapor contained in the air, divided by the maximum amount the air can hold, expressed as a percent. A relative humidity of 50% means the air contains ½ of the water vapor it can actually hold. The maximum amount of water vapor the air can hold is dependent upon the temperature (the “relative” in relative humidity). The higher the temperature, the more water (actually water vapor) the air can hold. For example, air with a temperature of 0°C can hold about 4.5ml of water. Air with a temperature of 26°C can hold about an 30ml of water.
So, what does this all mean? Sweat is evaporated (changes from a liquid to a gas, i.e. water vapor) when heat is added. The heat is supplied by your body. The results are summed up in the table below…
Relative Humidity |
Capacity for air to hold water |
Amount of Evaporation |
HEAT removed from the body |
low |
LARGER |
HIGHER |
MORE |
HIGH |
smaller |
lower |
less |
We, at the National Weather Service, as part of our mission for protecting life and property, have a measure of how the hot weather “feels” to the body. The Heat Index is based on work by R.G. Steadman and published in 1979 under the title “The Assessment of Sultriness, Parts 1 and 2.” In this work, Steadman constructed a table which uses relative humidity and dry bulb temperature to produce the “apparent temperature” or the temperature the body “feels”.
We use this table to provide you with Heat Index values. These values are for shady locations only. Exposure to full sunshine can increase heat index values by up to 10°C. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous as the wind adds heat to the body. The Heat Index Table is below.
Relative Humidity % | |||||||||||||
0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | |||
T e m p °C |
60 | 54 | 60 | 65 | 70 | 75 | 80 | 85 | 90 | 96 | 101 | 106 | |
50 | 44 | 49 | 53 | 58 | 62 | 67 | 71 | 75 | 80 | 84 | 89 | ||
40 | 34 | 38 | 42 | 45 | 49 | 53 | 56 | 60 | 64 | 67 | 71 | ||
30 | 24 | 27 | 30 | 33 | 36 | 39 | 42 | 44 | 47 | 50 | 53 | ||
20 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | 28 | 30 | 32 | 34 | ||
10 | 4 | 5 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
Remember, these values are in the SHADE. You can add up to 10°C to these values if you are in direct sunlight.
The chart below tells you the risk to the body from continued exposure to the excessive heat.
Category |
Classification |
Heat Index/Apparent Temp (°C) |
General Affect on People in High Risk Groups |
I |
Extremely Hot |
54°C or Higher |
Heat/Sunstroke HIGHLY LIKELY with continued exposure |
II |
Very Hot |
40°C – 54°C |
Sunstroke, heat cramps, or heat exhaustion LIKELY, and heatstroke POSSIBLE with prolonged exposure and/or physical activity |
III |
Hot |
32°C – 40°C |
Sunstroke, heat cramps, or heat exhaustion POSSIBLE with prolonged exposure and/or physical activity |
IV |
Very Warm |
26°C – 32°C |
Fatigue POSSIBLE with prolonged exposure and/or physical activity |
Wind Chill
The wind chill is the effect of the wind on people and animals. The wind chill temperature is based on the rate of heat loss from exposed skin caused by wind and cold and is to give you an approximation of how cold the air feels on your body.
As the wind increases, it removes heat from the body, driving down skin temperature and eventually the internal body temperature. Therefore, the wind makes it FEEL much colder. If the temperature is -11°C and the wind is blowing at 30km/h , the wind chill temperature is -20°C. At this level, exposed skin can freeze in just a few minutes.
The only effect wind chill has on inanimate objects, such as car radiators and water pipes, is to shorten the amount of time for the object to cool. The inanimate object will not cool below the actual air temperature. For example, if the temperature outside is -11°C and the wind chill temperature is -20°C, then your car’s radiator temperature will be no lower than the air temperature of -11°C.
The Wind Chill Chart
To determine the wind chill temperature, find the value closest to your outside air temperature. Find the value that most closely represents your present wind speed. Your wind chill temperature is the value where lines drawn from the air temperature and wind cross.
Air Temperature (°C) |
|||||||||||||||||||||
W I N D S P E E D km / h |
Calm |
4 |
2 |
-1 |
-4 |
-7 |
-9 |
-12 |
-15 |
-18 |
-21 |
-23 |
-26 |
-29 |
-32 |
-34 |
-37 |
-40 |
-43 |
||
8 |
2 |
-1 |
-4 |
-7 |
-11 |
-14 |
-17 |
-21 |
-24 |
-27 |
-30 |
-33 |
-37 |
-40 |
-43 |
-47 |
-49 |
-53 |
|||
16 |
1 |
-3 |
-6 |
-9 |
-13 |
-16 |
-20 |
-23 |
-27 |
-30 |
-33 |
-37 |
-41 |
-44 |
-47 |
-51 |
-54 |
-58 |
|||
24 |
0 |
-4 |
-7 |
-11 |
-14 |
-18 |
-22 |
-25 |
-28 |
-32 |
-36 |
-39 |
-43 |
-46 |
-50 |
-53 |
-57 |
-61 |
|||
32 |
-1 |
-4 |
-8 |
-12 |
-15 |
-19 |
-23 |
-26 |
-30 |
-34 |
-37 |
-41 |
-44 |
-48 |
-52 |
-56 |
-59 |
-63 |
|||
40 |
-1 |
-5 |
-9 |
-13 |
-16 |
-20 |
-24 |
-27 |
-31 |
-35 |
-38 |
-42 |
-46 |
-50 |
-53 |
-57 |
-61 |
-64 |
|||
48 |
-2 |
-6 |
-9 |
-13 |
-17 |
-21 |
-24 |
-28 |
-32 |
-36 |
-39 |
-43 |
-47 |
-51 |
-55 |
-58 |
-62 |
-66 |
|||
56 |
-2 |
-6 |
-10 |
-14 |
-18 |
-22 |
-26 |
-29 |
-33 |
-37 |
-41 |
-44 |
-48 |
-52 |
-56 |
-60 |
-63 |
-67 |
|||
64 |
-3 |
-7 |
-11 |
-14 |
-18 |
-22 |
-26 |
-30 |
-34 |
-38 |
-42 |
-46 |
-49 |
-53 |
-57 |
-61 |
-64 |
-68 |
|||
72 |
-3 |
-7 |
-11 |
-15 |
-19 |
-23 |
-27 |
-31 |
-34 |
-38 |
-42 |
-46 |
-50 |
-54 |
-58 |
-62 |
-66 |
-69 |
|||
80 |
-3 |
-7 |
-11 |
-16 |
-19 |
-23 |
-27 |
-31 |
-35 |
-39 |
-43 |
-47 |
-51 |
-55 |
-59 |
-63 |
-67 |
-71 |
|||
89 |
-4 |
-8 |
-12 |
-15 |
-19 |
-24 |
-28 |
-32 |
-36 |
-39 |
-43 |
-48 |
-52 |
-56 |
-59 |
-63 |
-67 |
-72 |
|||
97 |
-4 |
-8 |
-12 |
-16 |
-20 |
-24 |
-28 |
-32 |
-36 |
-40 |
-44 |
-48 |
-52 |
-56 |
-60 |
-64 |
-68 |
-72 |
What is important about the wind chill besides feeling colder than the actual air temperature? The lower the wind chill temperature, the greater you are at risk for developing frost bite and/or hypothermia.
Frostbite occurs when your body tissue freezes. The most susceptible parts of the body are fingers, toes, ear lobes, and the tip of the nose. Hypothermia occurs when body core temperature, normally around 37°C falls below 35°C. The following table shows how fast frostbite can occur at various wind chill temperatures.
Wind Chill |
Cold Threat |
-6°C to 4°C |
COLD. Unpleasant. |
-17°C to -7°C |
VERY COLD. Very unpleasant. |
-28°C to -18°C |
BITTER COLD. Frostbite possible. Exposed skin can freeze within 5 minutes. |
-56°C to -29°C |
EXTREMELY COLD. Frostbite likely. Exposed skin can freeze within 1 minute. Outdoor activity becomes dangerous. |
-57°C and lower |
FRIGIDLY COLD. Exposed skin can freeze in 30 seconds. |
The best way to avoid hypothermia and frostbite is to stay warm and dry indoors. When you must go outside, dress appropriately. Wear several layers of loose-fitting, lightweight, warm clothing. Trapped air between the layers will insulate you. Remove layers to avoid sweating and subsequent chill.
Outer garments should be tightly woven, water repellent, and hooded. Wear a hat, because half of your body heat can be lost from your head. Cover your mouth to protect your lungs from extreme cold. Mittens, snug at the wrist, are better than gloves. Try to stay dry and out of the wind.