HAARP
From Nerdhouse Projects
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High Altitude Amateur Radio Project
I'm planning to loft an amateur radio and camera payload to 100,000 feet MSL with a meteorological sounding balloon. I'm interested in taking pictures and recovering the camera after the flight. I originally planned on flying the gumstix computer to handle the shutter and activate the cut-away device to separate payload from balloon. I am now thinking I should go with a much more simple method and just whip up some code for a PIC microcontroller to do the same functions. $10.00 vs $130.00.
Flight System Components
| Payload item | Mass (grams) | Weight (pounds) |
|---|---|---|
| Kaymont KCI 1500 meteorological balloon | 1500 | 3.306 |
| Walmart styrofoam cooler | 317.8 | 0.70 |
| Parachute (60 inch) (approximate figures) | 340 | 0.75 |
| Yaesu / Vertex VX-150 2meter ham radio w/ stock antenna (1st) | 337.5 | 0.74 |
| Yaesu / Vertex VX-150 2meter ham radio w/ stock antenna (2nd) | 338.2 | 0.75 |
| TNC-X packet interface | 74.3 | 0.16 |
| Lassen SQ gps module w/ pigtail | 8.8 | 0.02 |
| Trimble mag mount antenna | 113.3 | 0.25 |
| Totals (excluding balloon) | 1529.9 | 3.4 |
Materials
Items Purchased:
- gumstix connex 400 single board computer
- two Yaesu VX-150 ham radios (2 meter ham band, .5, 2, and 5 watt power modes)
- Trimble Lassen SQ gps module and antenna
- Byonics "TinyTrak3" gps <--> radio interface board for APRS
- TNC-X packet modem / TNC
- 1 metric crapload of lithium batteries (AA size, 3.6 volts, SAFT model LS 14500)
- Kaymont KCI-1500 balloon
- styrofoam cooler
- Helium regulator (borrowed from Pat Turner)
Items Needed:
- directional 2 meter antenna for tracking
- camera of some sort
Real Time Tracking
The (near) real time tracking is now working just fine. I have a Byonics TinyTrak3 APRS position encoder wired up to the Trimble Lassen SQ gps module in the car. The data packets are being sent out at 5 watts through an old Yaesu FT-8500 dual bander on the APRS frequency of 144.390MHz. The actual payload will use a Yaesu/Vertex VX-150 handy talkie (HT) for this purpose.
Antenna Design
An antenna that does not require a ground plane would be ideal for this project. I built a twinlead J-Pole with extreme care to match specs. I noticed right away that it did not perform as well as the rubber duckie that shipped with the VX-150. I was able to use an Agilent Network Analyzer to make SWR measurements over the entire 2meter band. It was terrible! Every little curve in the twinlead would change the SWR measurment when flexed. I see no reasonable way to make this type of antenna practical when it's just so sensitive to physical distortion.
