Saturday, March 22, 2008

SDG-9 update

Tom, WB2YDS, is on Long Island and copied a good deal of telemetry last night before the balloon went over his horizon. Sunset was clearly visible in the data, as the internal temperature plummeted and the frequency of the transmitter drifted downward. The temperatures copied by Tom ranged from -9C at 2138z, down to -41C at 2322z.

The last two strings that he copied (at 2314z and 2322z) seemed to show the temperature leveling off at around -40C, which would indicate a float about 2km lower than the designed float altitude. If this is indeed the case, then we could have some problems - 2km lower means that we will run into a good deal more moisture on our northern voyage and possibly pick up ice. Just a bit lower yet - at around 7.5km in altitude - the entire trajectory changes and the balloon ends up floating aimlessly in the doldrums.

On the other hand, Pierre, KA2QPG, the designer of the beacon and my cohort in this endeavour, points out that the beacon itself gives off about 100mW of heat and could be skewing the internal temperature a bit. If so, then we could still be at 9-10km and heading in the right direction. We'll see.

At around 1800z today, *if* the balloon is on the right trajectory, it should be passing Newfoundland at about two hundred miles off the east coast. I've alerted some amateur radio ops in NL and they will be listening!

2 comments:

Anonymous said...

I have found an info about your flying balloon, but I miss any usefull info, as modulation, coding of message etc. do you have some page with details? or call sign of balloon to look for it at cluster? Thanks Tommy OK2PNQ

Andy said...

Can you please announce what sort of modulation you are sending on the beacon - CW/Morse? SSB? AFSK/FM/Packet and what a tlm decode would be?

many thanks

Andy G0SFJ


andythomasmail AT yahoo Dot co DOT uk