[chbot] Sundays balloon-adventure, report please

[André Geldenhuis]

Hi Chris

Sounds like a cool project :)  The reason we went with 10mW was that the
transmitter costs about $5 and weighs about 1 gram.  Our entire payload
including 2 cameras, spot tracker, electronics, batteries for 5hours + and
insulation etc only came to 900 grams and I reckon we can reduce the weight
some more.  10mW also saves on battery weight.  We also don't really need a
faster data rate unless we want to transmit video, which we have considered
doing.  Obviously our 4 baud data rate wouldn't be up to that :P

Cheers :)
Andre

On Tue, Jan 8, 2013 at 8:08 AM, Chris Hellyar <chris at trash.co.nz> wrote:

>  Hi Andre,
>
> Can I ask a possibly not relevant question: why only 10mW?
>
> There is unlicensed spectrum in the PRS band for telemetry, or you could
> get a ham involved and run licensed in the 70cm band (Although not that
> frequency, that's in the repeater uplink section of the band) .  Both
> options would let you run a higher bandwidth downlink.
>
> Just curious about the design decision as a rapid ascent balloon is one of
> my (many) unfinished projects.
>
> I made the payload container a couple of years ago and got as far as
> making the camera controller and researching GPS's. My cunning plan was to
> launch to time the burst with an ISS overhead pass and relay telemetry off
> the APRS digipeater on board.  It was my main motivation to getting my
> amateur license at the time, although now I've got the DX bug and that's a
> whole other bowl of cornies.
>
> Cheers, Chris H.
>
>
>
>
> On 07/01/13 23:58, André Geldenhuis wrote:
>
> Partial success I'm afraid :P
>
> The spot tracker stopped above 60k feet which we expected but I had hoped
> it would start working once below that again.  It appears not for whatever
> reason.     We also had a 10mW radio on board the balloon transmitting
> location, altitude and temperature which the recovery team managed to track
> all the way out to 80km with good decoding except when the balloon was low
> on the horizon.  The last GPS fix was at 3436m at a composite position of
> -44.04174, -173.04946.  The position is composite as the last two messages
> only contained one of latitude and longitude due to signal breakup.   It
> puts the payload out to sea south of akaroa harbour.
>
>
> The balloon ascended much slower than anticipated and we are not sure why
> yet, we are still going though the data to try and figure out what
> happened.  The slow assent was the reason the balloon went out to sea, it
> took much longer to reach its burst altitude.  Next time we will have cut
> downs :P
>
> We are hoping it washes up and someone finds it and returns it to us. The
> electronics will be wreaked but the two camera SD cards and data logger SD
> cards might still be ok and it would be nice to see the pictures :)
>
> We got about 80% of the objectives for the flight though and we planned to
> iterate all the electronics and replace the spot with a spot 2 which has a
> ublox GPS unit so will work above 60k feet.   We will fly the next
> iteration soonish.
>
>
> I'll let the list know if we get any picures back
>
> Cheers
> Andre
>
>
> On Mon, Jan 7, 2013 at 8:51 PM, Mark Atherton <markaren1 at xtra.co.nz>wrote:
>
>> Hi Andre,
>>
>> Looks like it was a sucess, well done.
>>
>> From http://goo.gl/1o6o6 password microprize ...
>>
>> Launch time close to 10:42, with signal loss 12:51, so just over 2 hrs
>> flight time (?)
>>
>> Not obvious what altitude you managed, or I haven't found the correct
>> button yet.
>>
>> Any chance of a quick report here and maybe a fuller report with photos
>> at the next Tait-meeting ?
>>
>> Regards,
>>
>> Mark
>>
>>
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>
>
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