Ham Radio Forum

My son Brenden Geary KJ6HVP plans to launch a weather balloon with 300mw repeater on board. This is for his 8th grade science project. He expects the payload to reach 100,000 feet and the repeater should cover 800 mile diameter. To hit the repeater set your radio to 144.8 RX /434.075 TX / Tone 250.3 He will fly next Sunday Feb. 27th weather permitting.

If you would like to know more check out his site www.BrendenGeary.com


Thanks,
Tim
KJ6HSX

Hi,

Congratulations to Brenden (and the entire work party) for the launch and successful deployment of the balloon repeater. I spoke with several stations, including KJ6HVP, via the cross-band repeater. After the launch, many were calling. It was a FBOM experiment to see performed, and the video / audio probably helped a lot of us get a feel for the amount of hassle and planning needed.

Worked the 434 MHz input with an FT530 handheld, and had an FT2800 for the VHF receive side. It looks like the APRS failed, however all should know that it could be heard on the 2m downlink from time to time at the start of the flight. Looks like it stopped after the first ten minutes or so.

Good luck to Brenden on his ham and academic career!

Will there be a web page documenting the whole thing? I suspect it is far too early for that, but something this grand should be publicized! I was especially curious to know where the package was found when back on the ground.... Around Lake Elsinore was the last I heard - and that was a predicted landing vicinity.

73,
matt zilmer, Upland, CA.
W6NIA
Harvey Mudd College, Class of 1979
mzilmer@hotmail.com

I was too far away to participate, but this project is very interesting to me. It deserves more publicity.

Randolph

Update…

The launch had a few bumps before it even left the ground. First the truck would not start the morning of the launch… not a great start. Next we ran out of helium… we must have had bad fills on the He tanks. No problem ran to the local party store and picked up another one. The balloons are held down with 5gal home depot buckets filled with water. The wind blew one of the balloons enough to tip the bucket over and the balloon flew into a tree. After it looked like the balloon was ok but we all knew it wasn’t. He flew two APRS trackers and they both failed. One failed because the coax attaching the ground plane just broke and the antenna fell. The other transmitted fine however it lost GPS lock and never regained it again. He flew a Spot tracker as a second backup, nice work Brenden. The damaged balloon popped around 60,000ft, shortly after he was able to make contact with a Phoenix AZ. By the time he figured out the balloon had popped, again we have no altitude data, we had visual conformation that it was somewhere around 7-15k. At this point he wanted to cut off the balloon with a hot wire circuit he designed, again nice job Brenden. I was worried that he would not be able to turn off the hot wire and possibly start a fire. Brenden was able to successfully cut off the balloon and turn off the hot wire before loosing contact with the repeater. When we knew we were close he turned on a siren to help locate it. His repeater was able to make contact with people from San Diego to Phoenix AZ. At approximately 300 miles Phoenix was his farthest contact. The payload few approximately 96 miles east. Its landing site was north of 29 Palms: 33.884 -116.25401. He was able to find it using the Spot however we do not have any altitude data.

Thanks to everyone for their help and support of this project. I would also like to give a special thanks to Allen at http://www.byonics.com Thanks again for all your help.

@Matt Brenden is going to Harvey Mudd tonight, he will watch static test of rocket motors.
@Randolph Yes Maine was just out of range.. Thanks for the support.

Check out his site:
http://www.BrendenGeary.com

Tim Geary
KJ6HSX
One Proud Dad…

There is much more involved in actually doing things like that most people realize. The idea of sending some radio equipment up with a ballon seems fundamentally simple, but there are plenty of potential problems and the reality of getting everything right isn't so easy. Projects like that are valuable learning experiences for young engineers.

P.S. I should have added -- and for old engineers too!

I agree that it is not as easy as it looks... it is also not as hard as some make it out to be. Brenden and I have flown 8 and we have made every mistake in the book... We did loose one payload and all the gear inside

I also forgot to thank Roger WA6ZVP, he really stepped up and helped out with this project