home 
wiki
wiki
ConnectingToTheNetworkFAQ
- Connecting to the network
- Where can I get the equipment?
- How do I get started?
- Can I use my Apple Macintosh and/or Airport hardware or not?
- How long can 802.11b wireless links go?
- What's the closest node to my house/office/mountain hut?
- When creating a node, how can you get the latitude and longitude required for locfinder from the Melway street directory?
- What is line of sight?
- How do I plot a node on a Melway map using longitude and latitude from locfinder?
- How do I use a magnetic compass to determine the bearing to a node?
- What GPS format is required in the Create New Node Form? My GPS has several Standard Formats
- What is a Fresnel Zone?
- How close or how far the two node has to be to establish connection?
Connecting to the network
Want details on what you need to get connected? You've come to the right place! If your question is not here, try looking through all of the questions which are listed on TheEvolvingFAQ.Where can I get the equipment?
Off the shelf at a retailer, or make it yourself.Why not start by looking at the TheIncredibleBulk
Have a look at the HomeBrew page to see things you can make for yourself.
If it's wireless gear you want to buy, HardwareSuppliers are not far away.
Be sure to check the HardwareDatabase first.
How do I get started?
See the Getting Started howto.Can I use my Apple Macintosh and/or Airport hardware or not?
Yes.You sure can! You can even get wireless with your Newton. Check out the Apple Wiki page.
Macs running OSX, Linux or *BSD are useful for running higher-level nodes which may require Unix-based routing tools. However, for a simple client node, you can get away with a much lower-end machine running the Classic MacOS - see AppleMacMinimumSpecs
Apple proposed the original 802.11b standard </trivia>. Their version of the hardware is marketed under AirPort brand. It is completely interoperable with other 802.11b equipment and networks.
You can connect to a Windows or Linux based Access Point or Client with your Airport hardware, and connect Win/Linux clients to an Airport base station. The Lucent/Avaya/Cabletron/Orinoco cards use the exact same chipset as the Airport cards, and are an inexpensive substitute if your Mac has PCMCIA slots. In fact, apart from the fancy case, the original Graphite Airport base station was just a 486 single-board computer running Linux, with an Orinoco PCMCIA card.
How long can 802.11b wireless links go?
Anywhere from 100m to 50km depending on conditions, up to 15km is achievable by most.It depends on many factors such as what the terrain is like between either end of the link, the quality of the antennas in use, etc. NodeGDW was running a marginal quality link of approximately 50km to NodeGHO for a length of time.
With enough power the only limit is the curve of the earth. Unfortunately, there are laws governing power output. Personally I've seen a guy doing 17km links, some Perth guys did 25km, O'Reilly says
33km links are theoretically possible and some guys in Spain have done 70.5km without any kind of power amplification. Granted, all of these links had very good line of sight to each other.But some believe the link is unreliable after 15km with default settings, at 11mb/s, but lower speeds can go farther.
Distance Limits for 802.11 has further information.What's the closest node to my house/office/mountain hut?
Take a look at Locfinder and the RegionalGroups.
When creating a node, how can you get the latitude and longitude required for locfinder from the Melway street directory?
Interpolate using the red lines, then convert from AMG.The links for looking up geographic coordinates on your node editing page (that is, the automatically or manually links) may not work if you have set your browser to suppress those annoying server-side pop-up advertisements. Even if the links are working, you may not be able to get a result from the automatically link or have difficulty finding your street on the manually link. The following method produces comparable results and is provided for hackheads like myself who enjoy a little calculator play.
The Melway street directory shows the Australian Map Grid (AMG) with fine, red, dotted lines at 1000 m intervals on the ground or 50 mm on the page. Where each red line intersects with the map border, small black numbers indicate the Easting ordinate (across the top and bottom of the map) and the Northing ordinate (up the sides of each map).
Unfortunately locfinder 2.0 does not use AMG co-ordinates, so you have to convert them to geographic coordinates -- latitude (parallel rings running horizontally around the earth) and longitude (rings running vertically around the earth and converging at the North and South poles). You can convert AMG to geographic coordinates with Redfearn's Formula.
Since it is unlikely that your node lies exactly on a red AMG line, you will have to get out your millimetre ruler to interpolate the correct Easting.
- Work out your Easting ordinate by interpolation.
- Find the two vertical Easting lines that your site lies between. (For example, my house lies between 332 and 333.)
- Measure the distance from the lower-valued line to your site in millimetres, multiply by 20, pad with leading zeros to make a 3-digit number if necessary, and append to the lower-valued easting value. (For example, my house is 7 mm east of 332, 7 X 20 = 140, hence 332140 for an interpolated easting.)
- Work out your Northing ordinate.
- Find the two horizontal Northing lines that your site lies between. (For example, my house lies between 5809 and 5810.)
- Measure from the lower-valued line to your site in millimetres, multiply by 20, pad with leading zeros to make a 3-digit number if necessary, and append to the lower-valued northing value. (For example, my house is 31 mm north of 5809 , 31 X 20 = 620, hence 5809620 for an interpolated northing.)
- Calculate your geographic coordinates.
- In any browser, go to
Redfearn's Formula for Grid to Geographic conversions.- Enter text in the Point Name text box to identify this point on the results page -- useful if you print out the page and store it. Your node name would be an obvious choice!
- Complete the Easting and Northing boxes with the values calculated above.
- Type 55 in the Zone text box and click Submit Data.
The Geoscience Australia site returns latitude and longitude in degrees, minutes, and decimal seconds.
Note: For those outside the Melbourne metropolitan area, Zone 54 lies between long. 138�° (between Kangaroo Island and Cape Jervis, SA) and 144�° (Winchelsea, VIC). Zone 55 extends from long. 144�° (Winchelsea, VIC) to 155�° (just beyond the easternmost point of Victoria at Cape Howe or Gabo Island).
- Convert degrees, minutes, and seconds to decimal degrees
- The latitude and longitude needs to be converted to decimal degrees for locfinder. For example, the AMG coordinates for my house at lat. -37�° 50' 43.53603" and long. 145�° 5' 31.85668" need to be converted to lat. -37.8454�° and long. 145.0922�°. Many scientific and engineering calculators have an hours.minutes.seconds-to-hours (decimal) function which can do this. Otherwise, do the following steps.
- Divide the decimal seconds by 60 to convert them to decimal minutes, and add them to the whole number of minutes. For example, for lat. -37�° 50' 43.53603", do 43.53603 / 60 = 0.7256; 50 + 0.7256 = 50.7256 decimal minutes. For long. 145�° 5' 31.85668", do 31.85668 / 60 = 0.5309; 5 + 0.5309 = 5.5309.
- Divide the decimal minutes by 60 to convert them to decimal degrees, and add them to the ABSOLUTE whole number of degrees, then apply the correct sign. For example, for lat. -37�° 50' 43.53603", do 50.7256 / 60 = 0.8454; 37 + 0.8454 = 37.8454�°; apply sign -37.8454�°. For long. 145�° 5' 31.85668", do 5.5309 / 60 = 0.0922; 145 + 0.0922 = 145.0922�°; apply sign +145.0922�°.
- Create or update your node record in Locfinder
Contributed by Hedley Finger, NodeGFK.
What is line of sight?
The imaginary line between two antennas for a wireless link.We have a more detailed description including some info on what a fresnel zone is.
How do I plot a node on a Melway map using longitude and latitude from locfinder?
Victorians can enter the address of your location and
search.How do I use a magnetic compass to determine the bearing to a node?
In Melbourne, Magnetic North is 11 (eleven) degrees east of True North. Locfinder gives bearings relative to True North. So if Locfinder says a node is at bearing of 90 degrees from you, it it will be a bearing of 79 degrees measured with a magnetic compass.
Remember:
- True North = 349 degrees on a magnetic compass
- Magnetic North = 11 degrees on a True-reading compass
What GPS format is required in the Create New Node Form? My GPS has several Standard Formats
Locfinder appears to use the AGD66 format for Latitude and Longitude.
FYI,
NodeDB appears to use GDA94 format. Don't quote me though. 
amino acids clothing The two formats differ by about 200 metres. - DanFlettWhat is a Fresnel Zone?
The line-of-sight page give a good description.How close or how far the two node has to be to establish connection?
How long is a piece of string?See the previous question on this page titled "How long can 802.11b wireless links go?".
Back to TheEvolvingFAQ
Version 22 (current) modified Mon, 26 Jul 2021 12:49:29 +0000
[EditText] [Spelling] [Current] [Raw] [Code] [Diff] [Subscribe] [VersionHistory] [Revert] [Delete] [RecentChanges]