[Space] Amateur Radio and Balloons

[Ed Moore]

Hi All,

Just by way of introduction, I thought I'd throw a brief comment upon some of the minutes of the meeting that you put up on your wiki.

Specifically:

    * HF ham stuff can reach a long way but takes lots of power
with good enough buoyancy control, could dip down to 3g altitudes,
download, re-ascend

To share some of our experiences: we're legally limited to 10mW radios on the 434Mhz (70cm) amateur radio band in the UK. This is to say, they are 'license free' and intended for use in car key remotes and so on. It's annoying and a bit unenlightened, but it's not going to change any time soon, so we live with it. The last launch, using the 10mW 434Mhz modules that UKHAS now use as standard (radiometrix NTX2) had the following flight profile:

http://spacenear.us/tracker/

All of the data comes from the 10mW telemetry link. It's modulated at 50 baud, using the amateur radio standard RTTY. It transmits all the useful housekeeping data (lat/long/alt, temps, voltages, whatever) roughly every 10s. The ground stations were off the shelf amateur radio equipment (the Yaesu 817 being a particular favourite), With a yagi antenna for when it goes long range.

By way of contrast, my 3G USB dongle consumes about 2-2.5W, and it's reception is obviously dependant on local infrastructure.

So I guess I would say not to write off ham radio stuff too early - you can do a lot with 10mW!

	- Ed

P.S. Can I plug the #highaltitude channel on irc.freenode.net It's the UKHAS channel, lots of geeks, couple of the founders of London Hackspace, generally lots of like minded people.

_______________________________________________________
Ed Moore,  CU Spaceflight (and UKHAS)   eam52 at cam.ac.uk    +44 (0)7789 933271

www.cuspaceflight.co.uk
flickr.com/cuspaceflight
vimeo.com/cuspaceflight