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[wxsig] Newbie question

Daron J. Wilson daron at wilson.org
Thu Mar 1 20:55:45 UTC 2007

> Our local sailing club would really like to know the wind
> speed/direction at a spot offshore.  NOAA doesn't have the budget to
> install a real weather buoy, so  it's up to me (us).  We think the
> USCG will allow us to place an instrument package on a navigation
> buoy in the area of interest, although installing it will be a good trick!
> Needs:
> 1) Wind speed/direction required
> 2) Able to communicate with base station about 1.8 miles away (good
> line of sight).
> 3) Solar panel operated. (Night time observations not important, so
> maybe no or very small battery?).
> 4) Marine environment (non freezing, but salt water and frequent gale
> conditions)
> 5) Low cost, since the USCG has a hard time just keeping the buoy in
> place, and it will probably be lost more than once.
> The Dallas Wind sensor seems like a reasonable input device, although
> sufficient accuracy might be possible with a wand with strain
> gauges.  I'm a competent PIC programmer, so that wouldn't be too
> challenging.  The 1.8 miles is the gotcha for me.  There are no
> available locations for repeaters, so I'm thinking it will have to be
> either a packet radio or possibly a cobbled-up FRS type personal walkie
> talkie.
> Any suggestions?

I think a fiberglass watertight enclosure (Hoffman or similar) would be
where I would start.  Inside there I'd try to fit a low power VHF radio,
Kantronics KPC3+ TNC and possibly a Peet Bros Ultimeter 100 weather station.
Our APRS weather stations http://www.ocrg.org/telemetry_feed/ocrgwx.html use
commercial mobile radios for more power, the KPC3+ which has been modified
for our telemetry needs, our custom made telemetry adapter which gets a
digital input and a couple analog inputs, and a device we make called the
WeatherDOG which takes the Peet data stream and 'massages' it with a PIC
before sending it to the TNC.  This is done primarily to make the weather
data standards compliant so it will show up on the Kenwood APRS radio
displays (mobile and portable), but secondly we have an option in the
WeatherDOG that allows the data to be 'human readable' and spits out the
weather data in a UI packet with it in clear test format so you could easily
parse it or just read it on a computer screen.

Many ways to do this of course, power will certainly be your challenge.  I'd
use some photo sensor to shut the thing off at night if you want to
conserver battery, using a couple of gel cells and a small solar panel for
maintenance.  If all you really want is wind speed and direction, I guess
you could take the output of the anemometer and feed it into the PIC, write
a bunch of code, and get what you want.

Another off the shelf option (more power required) would be the CAT200
repeater controller with the computer interface, connects directly to the
Peet weather station and a two way radio, simple DTMF query to the radio and
the synthesized voice could read back the wind speed and direction for you.

Sounds fun, good luck on the installation!



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