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Alan VE4YZ

Member Since: July 7, 2010

Country: Canada

  • Nate, check this
    to calculate radio foot print.
    60000' can be heard from 350 miles if you have the "big ears" on the ground to get that signal. Yagis, low noise preamps etc - all the stuff amateurs use to chat on satellites sub 1 watt over several thousand miles line of sitght.
    TX power at the balloon can be quite low... 300mw on 144.390MHz. As long as you don't need to communicate with the payload for such things as triggering a cut down the power budget which translates into weight of batteries is a bigger consideration.
    a 3 hour flight should give you 90,000' ( 1000'/min going up ) we have found little concern for keeping things warm up there. No convection will keep things warm. Camera batteries seem to heat the most snapping pictures every 15 seconds will get nice and toasty.
    Alan VE4YZ

  • Excellent Nate!
    I read from your profile that your are fluent in 2 languages. The seconds is the most important and now you have another challenge... document the GPS receivers you have on SparkFun and note whether they do 60,000' and/or 100k as long as only one of those parameters are violated - 60k feet.
    But we mere mortals have to dig deeply through those datasheets to find those that will work for us on HAB.
    Much success on future launches.
    Alan VE4YZ

  • posted on DIYDRONES in part
    ... I suggest that you seriously consider adding a transponder on the amateur bands. I'm sure local CO hams would willingly assist and you can run amateur equipment i.e. TX with out a licence when supervised by a licenced amateur at least for the GPS data. You will have ham ground stations who will track your launch including setup such as we use here http://www.wincube.ca/bcube.html and http://www.wincube.ca/amateurradio.html . We use 300mw transmitters at 144.390 MHz for GPS data and signals are heard up to 50 miles with piano wire omni directional antennas mounted horizontally 1/4 wave 19 1/2 inches aprox. Less antenna than I have on my EZ-Star for 72 MHz If the balloon goes beyond local reception another amateur will surely hear your beacon and GPS and relay it to the internet where to can track in almost real time at www.aprs.fi.
    Alan VE4YZ

No public wish lists :(