$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
https://amsat-uk.org/2014/01/22/50sat-pocketqube-two-months-after-launch/

$50SAT PocketQube two months after launch

Yaesu handheld and $50SAT 1.5U PocketQube

Yaesu handheld and $50SAT 1.5U PocketQube

Michael Kirkhart KD8QBA reminds us that the PocketQube $50SAT has now been operating for two months. He writes:

It has now been 2 months since the launch of $50SAT into its 625 km (approximate) sun-synchronous orbit, and as of this morning [Tuesday January 21], it is still operating.

It is getting cold again in EN82 land, so it is not likely I will be able to gather RTTY telemetry during the next few days, as my trusty netbook will not likely be able to deal with the cold for very long. Hopefully, everyone else can “pick up the slack” for me. I will still go out and monitor passes, provided it does not get too cold.

$50SAT Boards

$50SAT Boards

Since it was pretty cold this morning (about -12 to -13 degrees C), I chose not to record the pass at 15:24 UTC (10:28 AM local time). Instead, I monitored it using my FT-60. At about 15:36 UTC, I heard the codespeed on the FM Morse beacon drop, which indicates the availability of solar power. Using gpredict, I estimated the latitude of the satellite sub-point (the point on the Earth directly underneath the satellite) to be about 24 degrees N. Today, the sun is directly over 20.4 degrees south latitude (23.5 degrees * sin(270 + 30), as it has been about 30 days since the winter solstice). At the time I heard the beacon, the angle of $50SAT normal to the sun (assuming the passive magnetic stabilization is working) would be about 24 – (-20.4), or about 44.4 degrees. This means the solar radiation intensity is about 70% of its maximum value, which means the solar power generating capacity will be anywhere from 50% to 70% of its maximum, depending on whether one or two panels are facing the sun. But since I did not collect telemetry, I have no values for comparison.

I was able to collect RTTY telemetry on Sunday and Monday, and here it is:

2014-01-19,16:34,$$$$50jAT,128,,467,,,52,3,,21,142,82,,102,305,3662,*43
2014-01-19,16:36,b50SAT.128,,467,,,54,3,,21,139,82,,102,305,3683,*46
2014-01-19,16:39,$50SAT,128,,467,,,59,3,,21,132,83,1223cr}

2014-01-20,16:55,50SAT,128,,471,,,60,3,,21,132,83,,122,309,3683,*42

Michael Kirkhart KD8QBA
$50SAT team

$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.

$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 team seek help from radio hams

Yaesu handheld and $50SAT a 1.5U PocketQube

Yaesu handheld and $50SAT a 1.5U PocketQube

The $50SAT team is asking for help in capturing telemetry from the amateur radio 1.5U PocketQube satellite $50SAT on 437.505 MHz (+/-9 kHz Doppler shift) CW.

$50SAT Boards

$50SAT Boards

We are trying to determine the charging characteristics of the power system. The three team members all live above 40 degrees north and the satellite does not warm up enough during nighttime N-S passes to allow charging to begin. None of us are usually around during the daytime S-N passes and we would particularly appreciate telemetry reports when the satellite is in daylight.

Any form of report is welcome: decode of the fast Morse (120 WPM), RTTY demod, audio recording or I/Q capture from a FUNcube or RTL dongle would be greatly appreciated.

A link to a detailed description of the communications package can be found on the $50SAT website, http://www.50dollarsat.info/. The last distribution of Keps from AMSAT contain good elements for $50SAT.

$50SAT a 1.5U PocketQube

$50SAT a 1.5U PocketQube

$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.

Thanks,
Howie DeFelice AB2S
Email: howied231<at>hotmail.com

$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.

The $50SAT team plan to make all the software and hardware designs freely available to anyone who wants them for personal or educational use. For further information see the $50SAT Dropbox at https://www.dropbox.com/sh/l3919wtfiywk2gf/-HxyXNsIr8

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

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

HOPE RFM22B FSK transceiver http://www.hoperf.com/rf/module/fsk/RFM22B.htm

PICAXE-40X2 microcontroller http://www.picaxe.com/Hardware/PICAXE-Chips/PICAXE-40X2-microcontroller/

Revolution Education http://www.rev-ed.co.uk/

$50SAT Eagle2 PocketQube Operational
https://amsat-uk.org/2013/11/22/50sat-eagle2-pocketqube-operational/

Dnepr satellites https://amsat-uk.org/satellites/dnepr-november-2013/

$50Sat Eagle2 PocketQube Operational

$50SAT-Eagle2

$50SAT-Eagle2

$50SAT – Eagle2 – the PICAXE and RFM22B micro satellite was successfully launched from Dombarovsky Air Base in Russia on November 21 at 07:10 UT.

It went active soon after being released from UNISAT-5 and the 437.505 MHz (+/-10 kHz Doppler shift) Morse beacon from $50SAT was heard in the UK at 10:28 that morning (Nov. 21).

$50SAT is a very low cost and simple satellite and most radio amateurs should be able to receive the Morse beacon and FSK RTTY data with an omni directional antenna.

The primary purpose of $50SAT (Eagle2) was to create a cost effective platform for engineering and science students to use for developing real world skills. The PocketQube form factor has no precision mechanical parts and can be built from locally obtained sheet metal.

$50sat is comprised of two 40mm x 40mm circuit boards. The first is the processor/radio board which contains the PICaxe 40X2 processor programmed in PICaxe basic, the Hope RFM22B single chip radio and some peripheral devices. The PICaxe 40X2 is an easy to use micro controller popular in the education sector.

The second board is the power control and monitor board. This board contains four maximum power point controllers, one for each solar array on each side of the spacecraft as well as current monitors for the battery and summed solar power. The battery is a common 3.7 volt lithium ion camera battery.

The satellite will transmit data telemetry about the satellites operation, a sequence of call signs in slow FM Morse and some key data as fast FM Morse (120 WPM). The main data payload will also be transmitted as FSK RTTY which should be readily heard on the ground with basic amateur radio equipment.

$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.

The $50SAT team plan to make all the software and hardware designs freely available to anyone who wants them for personal or educational use. For further information see the $50SAT Dropbox at https://www.dropbox.com/sh/l3919wtfiywk2gf/-HxyXNsIr8

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

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

HOPE RFM22B FSK transceiver http://www.hoperf.com/rf/module/fsk/RFM22B.htm

PICAXE-40X2 microcontroller http://www.picaxe.com/Hardware/PICAXE-Chips/PICAXE-40X2-microcontroller/

Dnepr satellites https://amsat-uk.org/satellites/dnepr-november-2013/