Flight 2002B   -   SKY-EYE III
Flight Announcement

Tuesday, November 12, 2002 9:30 PM

Weather permitting, the Loudoun Amateur Radio Group will launch its SKY-EYE-III mission on Saturday, 16 November, 2002.

The flight train will consist of the veteran "Hot-Chips" payload (so named because the linear regulators used in the electronics package keep the interior a toasty +50 C during the flight) and an upgraded SKY-EYE package boasting three still cameras with a timed exposure script. One camera will again point straight down to give us low altitude shots for launch and landing, and two side-lookers that will provide high altitude horizon views mid-flight.

Flight telemetry will be downlinked on 145.65 MHz, FM, with a Morse-keyed audio tone at about 20 WPM.

Telemetry format is as follows:

DE K4LRG/B FFFFF / AAAAA / BBBBB / VVVVV /OOOOO / IIIII / RRRRR AR

DECODE AS FOLLOWS :

AAAAA = Telemetry Frame Number Since Activation at one frame per minute (Gains about 1 frame per hour)
BBBBB = A/D Converter raw output from the pressure sensor
VVVVV = Battery Voltge in millivolts
OOOOO = Air Temperature in K (subtract 273 for C)
IIIII = Payload interior temperature (subtract 273 for C-you'll see why it's called "Hot Chips")
RRRRR = Raw A/D converter counts of a reference voltage

To convert the Altimeter counts to millibars (or hecto-pascals),

mb = (Counts/3.37) - 203 will get you within a couple.

To figure altitude try
=IF(C10>222.27,(1-10^(LOG10(C10/$B$2)/5.2558797))/0.000006875586,36089.24+(LOG((C10/($B$2*0.2233609)),2.7182818)/-0.00004806346))

in your spreadsheet. C10 is the pressure in mb and $B$2 is sea level pressure 1013.24 mb

I seem to recall having to use the natural log because of a quirk in my spreadsheet.

On the last flight the signal was heard by N4PD/M in Connecticut, so keep an ear out for us on Saturday.

Numbers: Balloon : Kaysam 1000 g latex "Hot-Chips" : 1.45 kg using modified HT-200 tranmsitter, AD590 temperature sensors and a Mocroswitch 140PC type pressure sensor. Analog levels are digitized by an LTC1290 ADC and the processor is a Basic Stamp II SX. Power is supplied by 8 lithium ion cells (2 stacks of 2 7.2 volt cell phone batteries) providing over 12 hours of operation. Payload Engineer is Tom Dawson WB3AKD

SKY-EYE III consists of three Canon Snappy LX II 35mm still cameras each tripped independently by a PIC micro controller. The cameras and circuits are enclosed in a rigid foam airframe. Payload Engineer is John Rehwinkle KG4L.

John and Tom will man the launch site.

Numerous LARG members will be dispersed on the high ground around the Shenandoah Valley to monitor the telemetry and take bearings on the signal during the flight. Bearings will be relayed to Mission Control at Craig, N4OHE's QTH where the various bearings will be evaluated to arrive at an estimate of the Balloon's location. Telemetry will also be monitored at Mission Control to keep up with the progress of the flight.

Team Leads are John Unger, W4AU at Mission Control, Dennis Boehler, KF4TJI for tracking/recovery, and Tom Dawson, WB3AKD for launch.

See history.k4lrg.org for up to the minute information

73

Tom
WB3AKD
Loudoun Amateur Radio Group
High Altitude Balloon Project Chair