Author Topic: The DRA818 module transceiver on Balloon.  (Read 75 times)

Anton Janovsky (ZR6AIC)

  • Administrator
  • Jr. Member
  • *****
  • Karma: +0/-0
The DRA818 module transceiver on Balloon.
« on: June 11, 2018, 10:54:04 am »
Balloon Project.



Feedback
Just wanted to give some feedback regarding the DRA818 module I bought from you. We used it in our high altitude balloon this past saturday hooked up to raspberry pi zero to make a rudimentary sstv came. It worked great! We even got confirmation of perfectly received images in Bloemfontein and Secunda. Unfortunately the actual camera came loose in the payload so most of the images were useless (inside of the payload). But the concept worked great! I used the pi pwm output to generate the sound (through a filter) that was connected to the mic of the dra818 module. PTT was switched with a transistor also from the pi. On the pi I have a bash script that got executed every 5 minutes. It took a picture. Added overlay text, converted to a sound clip with the sstv encoding and then played over the pwm pins. The dra818 module was used at low power setting (think about 400mW?). Also used a diy dipole antenna on the payload (not pictured)

Final prototype:



Next step is to make it smaller and more power efficient, but very happy with the results :)

Anyways, figured you might like some feedback.

Thanks for the shop, have more purchases lined up for payday.

Regards,
Tom
(ZR6TG)
« Last Edit: June 11, 2018, 11:09:04 am by Anton Janovsky (ZR6AIC) »