HARDWARE DESCRIPTION

Our balloon team put together the balloon payload in 3 main parts:

• Styrofoam enclosure
• HF beacon and antenna
• VHF transceiver, TNC/GPS, and flight computer

STYROFOAM ENCLOSURE

The styrofoam enclosure was 3 cm thick styrofoam, glued together with marine silicone. It was designed to insulate the load from the extreme cold of high altitude, and provide cushioning on landing. Given the fact that there are over 100,000 lakes in our province, the payload was also designed with floatation and minimal water intake in mind! 3 cm of non-conductive foam was used for additional padding in the bottom of the box as well. Silver mylar covered the box to assist in RF shielding from the antennas, serve as a ground sink and as a radar reflector (unfortunately, the new radar in the Winnipeg area will filter out slow - moving small objects, so it wasn't useful in this regard). The box was built by Arne VE4ARN and Paula VE4MHZ.

The HF beacon was built from scratch by Vern VE4ABE, while the CW ID'er was build from scratch by Tom VE4TRT. This was designed to transmit on 28.090 Mhz, from a helically - wound antenna 1.4 m wide, using horizontal polarization. The antenna was mounted at the top of the enclosure.

HF BEACON AND ANTENNA

We used the new MFJ digital 2M radio on 145.790 Mhz (APRS frequency). It was connected to a Paccom Tiny - 2 TNC with a Trimble SVeeSix - CM3 GPS OEM board configured with NMEA output. It also had the conics limitation turned off (so it doesn't give up at 40,000 ft altitude!).

VHF ANTENNA

The 2M antenna was an end - fed 5/8th wave monted for vertical polarization at the top of the payload. The antennas were designed and built by Vern VE4ABE and Gord VE4GLS.

VHF TRANSCEIVER, TNC/GPS, AND FLIGHT COMPUTER

GPS data was transmitted every 59 seconds, along with telemetry data that included temperature inside and outside the enclosure. The temperature sensors used were National LM134H-3 units, which have good linearity right from -80 deg C to 40 deg C, the range we are interested in. Additional telemetry gave us the battery voltage and the humidity from a sensor robbed from a canibalized Space Data Corporation surplus radiosonde. The flight computer was a Microchip PIC16C71. The computer was programmed by Craig, VE4CET, with the help of Mike, VE4MJM. Alex, VE4AIM, provided advice on getting the PIC initially set up.

PARACHUTE

The parachute was designed as a scaled - down version of that used for payloads from the Black Brant sounding rocket (designed and built here in Winnipeg, by the way!). It used 2 square sections of strong nylon, 60" long by 22" wide. 40 lb. test multifilament fishing line ties the payload to the parachute in such a way to prevent tangling - 60" of line went to 3 points of each of the 4 edges of the parachute, and were tied to each of the 4 sides of the top of the payload, to the ends of a nylon mesh bag that completely covered the enclosure. The parachute and nylon enclosure was put together by Andy Minkevich (and sewn by Gail Tessier).

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