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Choices |
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Installation |
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Setup |
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Off-the shelf – |
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Professional Installations - Davis |
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High Quality Amateur Installations -
WM-918/WX-200 |
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Home brew – |
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Tucson Amateur Packet Radio Corp - TAPR |
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WA6YLB |
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Marketed under many names, for many prices |
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In Australia available from DSE: |
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Catalogue number D3960 |
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Price $398 |
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Targeted for cost-effective stand-alone APRS
use. |
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Also makes a great stand-alone weather station. |
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Also makes a great general-purpose 1-Wire
development platform. |
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Can be solar powered. |
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Reliable all-digital sensors. |
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All readings averaged for better accuracy. |
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Sensors and features Now: Wind Speed, Wind
Direction, Temperature, Rain, Real-time-clock, Humidity. Next: Transfer to
PC. Soon: Barometric Pressure |
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USD134 plus shipping (Feb 2001) plus sensors |
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Complete home brew solution |
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Detailed advice on sensor building |
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Info for main board PCB |
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Source code for Z80 processor |
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Must be sited to allow accurate readings |
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Airport standards a good guide |
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Wind |
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Temperature & Humidity |
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Rain |
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Barometric Pressure Settings |
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Clear of obstructions that may effect: |
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Direction (turbulence) |
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Speed |
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Located to obtain true shade temperature |
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Out of direct sunlight
(Remember to allow
for morning & afternoon,
summer & winter) |
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Avoid radiated heat |
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Be aware of humidity effects |
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Must receive correct rainfall: |
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Avoid splash back from walls, etc |
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Watch run off from stepped rooves, etc when
rainfall is very heavy |
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Remember garden sprinkler systems |
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Avoid blockages (leaves!) |
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Altimeter is a barometric pressure device |
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Accurately measures relatively small variations
in altitude |
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Note the importance of barometric pressure –
aircraft are constantly updated with current values to set altimeters
correctly |
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Must allow for height above sea level of your
barometric sensor |
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Hence altitude will effect reading |
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WX Stations allow for adjustment |
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Calculation is:
For each metre you are
above the Mean Sea Level you add .11717 millibars to your Barometric
Pressure reading. So if your altitude is 500 mtrs and the local pressure is
960mb add 58.59mbs (.11717 * 500) to your reading to get the MSL pressure
of 1018.59mb. |
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The two most popular seem to be: |
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WXView |
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FreeWX |
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I must confess that I use FreeWX but that is a
personal bias based on support for Australian developers, good price, great
support and excellent integration… |
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Written by Andy Keir of Forster in NSW |
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Supports UIView for APRS |
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Free ware |
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Also available – vidcap which captures a video
image, overlays with date & time plus user data |
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Produces data for web pages and other
requirements |
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These can be overlayed on your graphic by using
a program called AWXRadar |
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AWXRadar is a Program that automatically
downloads the latest Australian Bureau of Meteorology Weather Radar Images
from their web site. The program places the WX Radar images in a nominated
sub-directory, which can be your UI-View Maps directory. If you have a .INF
map reference file of the same name as the image in the directory, UI-View
will load the WX Radar Image as a UI-View Map and display it. |
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AWXRadar was written by John KB2SCS |
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A web page can be created incorporating the data
output from your WX software |
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For FreeWX you simply insert the tags in your
html and the data will appear. |
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Alternatively use the standard web page
generated by FreeWX and use the automated ftp feature to send it to your
site |
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FreeWX also allows the weather data to be
emailed |
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Simply enter the email address and frequency |
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The data will then be sent via your SMTP server |
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Beacon settings are critical. Remember, too much
data can slow down the network; too little data and your customers are not
serviced properly |
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A beacon setting of 15 minutes is more than
adequate for normal weather usage |
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If some critical situation exists you may adjust
that temporarily but be aware of the impact if all stations are adjusting
their beacon timing |
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There are many sites on the web and undoubtedly
there are quite a number linking to the APRS WX stations. Two that are well
known are: |
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findU |
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LIveWX |
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findu has many variations for getting data on
APRS stations |
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For WX stations a good start is http://www.findu.com/cgi-bin/wxpage.cgi?callsign |
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This site gives historical data for the selected
station including |
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Temperature, dewpoint, wind, barometer for last
five days |
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Rain for current day |
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Broadcasting WX data makes it available to many
interested parties |
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Local drive-in theatre for patronage |
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Nearby bowling club for weather movement |
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Who knows? |
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But who should initiate this? |
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The old chicken and the egg question – identify
users and then provide data? Or provide data then create users? |
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The reality is that if the data is provided in a
reliable, regular and quality format users will emerge. |
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But most of all, it is FUN. This is a hobby
after all. |
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However, speaking personally, it has made me
more aware of the weather conditions |
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It is no longer just an item at the end of the
news, telling me if I should carry an umbrella or not! |
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And, if you have young people in your household,
it can be educational |
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http://www.ae5pl.net/html/wx.htm - Live WX |
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http://home.iprimus.com.au/andykeir/freewx.html
- FreeWX software |
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http://www.skyview.co.uk – WXView software |
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http://www.theworks.com/~wa6ylb/wxstn.htm -
WA6YLB home brew |
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http://www.beals5.com/wx/ - TAPR home brew |
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http://www.findu.com/cgi-bin/wxpage.cgi?call=callsign
- wx station report |
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http://www.ofcm.gov/siting/text/a-cover.htm -
sensor standards |
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http://www.aprs.net.au/awxradar.htm - radar
image overlay |
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I hope this has been useful |
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And that you get as much pleasure out of APRS
and WX as I do… |
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Thanks for your attention… |
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Howard Small – |
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VK3DLH |
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Email – howard@small.com.au |
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Notes