[aprssig] flying digipeater?

Scott Miller scott at opentrac.org
Mon Apr 18 13:14:54 EDT 2005


I thought about this for SAR, too.  Around here anyway you'd probably want
it to be at least a few hundred feet up.  You've got wind to worry about,
plus the difficulty of filling and deploying it in the field.  And carrying
around a heavy K size helium cylinder.

Might be more practical if you could get by with a smaller, tougher balloon.
A digi would only need to be slightly heavier than a handheld radio, really.
You could get it lighter if you went with more expensive lithium batteries.

Scott
N1VG

----- Original Message ----- 
From: "Wes Johnston" <aprs at kd4rdb.com>
To: "TAPR APRS Mailing List" <aprssig at lists.tapr.org>
Sent: Monday, April 18, 2005 10:03 AM
Subject: [aprssig] flying digipeater?


> I just saw an article on slashdot about a stratolite... a communications
> satellite that will hover over an area at 65,000 feet (yeah right....)
> They say it's above the jet stream, but I know better... hope their
> solar powered craft can "hover" in a 100mph head wind.
>
> Never the less, it got me thinking.... what if we could use a digipeater
> at 100'?  or even 75'?  High enough to be over a 70' pine tree...
> Provide coverage for SAR teams
>
> a 1200g weather baloon can lift 9lbs right?  How light can we make a
> digipeater?  what about those promotional balloons car dealers often
> use?  a d7a walkie won't digipeat, so it's out... a pocket tracker won't
> receive, so it's out....  I'm thinking just use a kpc3 and a walkie
> talkie with a 1.7 or 2AH battery.
>
> Of course when the wind blows, it will surely pull the balloon off to
> the side and cause it to descend.
>
> A reel with kevlar line on it would be light.... anyone know how light?
> The weight the balloon has to lift must include the tether line too.
> Are these balloons suitable to be reused?  Could we make a large net
> (like one of those cheap charlie camping hammocks) to fit around the
> balloon to reduce wear and tear on the nozzle?  Suspend the load from
> the hammock/net instead of the nozzle?
>
> A company called datahunter makes a rs232 radio link called "the tick"
> that is parasitically powered from the RS232 port.... perhaps that would
> be used for a data link from the ground station?  It works for 350' line
> of sight at 10,000 bauds.  http://www.datahunter.com/Tick_DataSheet.pdf
>
> What about flying a WIFI range extender?  That would allow us to do
> video conferencing from laptop to laptop....  What about using digined
> running on linksys wrt54g with something like TNC-x on a serial port?
> Then we'd have wifi access and an APRS digipeater in the sky.
>
> Just food for thought....
>
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