$50SAT Effect of temperature on battery

Yaesu handheld and $50SAT 1.5U PocketQube

Yaesu handheld and $50SAT 1.5U PocketQube

The following information was posted to the $50SAT (437.505 MHz) PocketQube Yahoo Group:

This is the data from a pass a couple of weeks ago. By noting the audio frequency of the Morse audio, you know what the battery voltage is, so this can be used together with the RTTY to monitor the change in battery voltage as the temperature rises.

The temperature sensor in on the radio\processor PCB, not the battery, so its likely the battery temperature is lagging behind a bit.

The seconds are the time since $50SAT came out of Eclipse and should have therefore started warming up.

Pass Starting 10:55:04 10/01/2014
Time out of Eclipse in Seconds Mode Temp mVolts
463 RTTY -22 3662
534 Morse 3662
568 RTTY -19 3662
642 Morse 3683
725 Morse 3683
744 RTTY -13 3683
850 Morse 3683
915 Morse 3702
945 RTTY -8 3702
995 Morse 3702
1024 RTTY -3 3702

$50SAT is one of the smallest amateur radio satellites ever launched at 5x5x7.5 cm and weighs only 210 grams. Transmitter power is just 100 mW on 437.505 MHz (+/-9 kHz Doppler shift) FM CW/RTTY. It uses the low cost Hope RFM22B single chip radio and PICaxe 40X2 processor.

The electronics of the $50SAT PocketQube cost about $50 which is where the name came from. It also required solar panels which cost a further $150.

$50SAT has been a collaborative education project between Professor Bob Twiggs, KE6QMD, Morehead State University and three other radio amateurs, Howie DeFelice, AB2S, Michael Kirkhart, KD8QBA, and Stuart Robinson, GW7HPW.

Further information in the $50SAT Dropbox https://www.dropbox.com/sh/l3919wtfiywk2gf/-HxyXNsIr8

There is a discussion group for $50SAT http://groups.yahoo.com/groups/50dollarsat/

50DollarSat http://www.50dollarsat.info/

$50SAT PocketQube two months after launch