434 MHz balloons launch this weekend

21:18 Fernando Luiz de Souza 0 Comments






A number of 434 MHz balloon flights are planned for this weekend, one will have live web streaming of the launch and the chase car

On Saturday Anthony Stirk M0UPU will be launching a single payload with three trackers call signs as follows :
PAVA-A 434.500 RTTY 50 7N2
PAVA-B 434.525 DominoEX22
HABDUINO 434.450 RTTY 50 7N2

Chris Stubbs M6EDF will launch Cheapo on 434.300 MHz and Matt celebrating his super GCSE results will launch two trackers
NORB = 434.650 (Will probably be below this slightly)  8N2
PAVA = 434.552 7N1
Saturday's Raspberry PI balloon launch at around 10:30 by Dave Akerman M6RPI is a single balloon with 2 payloads, each one transmitting SSDV and telemetry.

SSDV picture from a PIE balloon – Image credit Dave Akerman M6RPI
The main payload is called PIE. This has a cutdown mechanism that will release the second payload (TED) at 39km or when it senses a burst.  Obviously 39 km isn't guaranteed even though the payloads are both relatively lightweight (less than 400g total) and the balloon is a 1600g Hwoyee filled with H2.

39 km is 31 metres over Felix Baumgartner's record jump altitude, in case you wondered why it was chosen!

Both trackers are Model A RaspberryPi boards each with UBlox GPS, NTX2B transmitter, Pi Camera module.  TED's camera is where his right eye used to be, and will look outwards for a normal view.  It's in at a bit of an angle so the shots will tend to be at that angle on average.  PIE's camera is directly above TED, looking down.  So for most of the flight it will mostly see the top of TED's head.

Both payloads change what they do with their cameras depending on altitude. At low altitude (<2 km) the transmitted images are small (320x240) and above that a bit larger (512x384). Also, both are programmed to take a short video of when Babbage is released. Depending on timing between the camera side and the transmission side, there may be a short period when no image is transmitted while the camera is recording video.

Additionally, full resolution 5 MP images will be taken and stored when above 2 km.

PIE is set to release TED as soon as it detects an altitude of 39000m or greater. This check is done on every new reading from the GPS and triggers a MOSFET-driven resistor cutdown, which should release TED after 2 seconds or so. It will also trigger below 39 km if it detects a balloon burst.

To configure dl-fldigi just choose BABBAGE in the drop-down list, then choose TED or PIE (makes no difference as they have the same settings) then hit autoconfigure. Or do it manually:  Carrier shift 600 Hz, 600 baud, 8 bits, 2 stop bits. Nominal frequencies are 434.200 MHz (TED) and 434.250 MHz (PIE).

To view the images as they come in, choose View - SSDV in the menu.  You don’t need to do anything else different to normal.  You will see the binary image data coming in between telemetry strings, but of course it will just look like garbage. So long as you see the lime-green "Successfully decoded image packet" window then all is good. Telemetry is interlaced with the SSDV packets so you'll see that coming in too.

Live streams from launch site and chase car:
http://www.batc.tv/streams/ukhas
and
http://www.batc.tv/streams/ukhas2

All SSDV images: http://ssdv.habhub.org
(or you can select either payload with http://ssdv.habhub.org/TED or http://ssdv.habhub.org/PIE )

The real-time track of all 434 MHz balloons will be at
http://www.spacenear.us/tracker

Beginners Guide to Tracking using dl-fldigi
http://ukhas.org.uk/guides:tracking_guide

To get details of upcoming UK balloon launches subscribe to the UKHAS Mailing List by sending a blank email to this address:
ukhas+subscribe@googlegroups.com

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