For radio operators

Teleme­try and bea­con data from F-1 con­tain crit­i­cal infor­ma­tion about the satellite’s health (bat­tery & solar cell volt­ages, tem­per­a­ture read­ings) and they are very impor­tant to us. This is our first space mis­sion so we would like to ask the ama­teur radio com­mu­ni­ty to help in track­ing and receiv­ing data from F-1 Cube­Sat. You will receive the ver­i­fi­ca­tion card from us!

Here is a quick sum­ma­ry on F-1’ fre­quen­cies:

145.980 MHz: main chan­nel, 1W RF out­put, FM, AFSK 1200bps, one teleme­try pack­et every 30 sec­onds, oper­ates in the dark by default (but can be com­mand­ed lat­er to oper­ate in sun­light as well)

437.485 MHz: back­up chan­nel, 0.2W RF out­put, FM, PWM CW bea­con, each bea­con trans­mis­sion lasts about 20 sec­onds then 90 sec­onds delay, only oper­ates in sun­light

1. Lat­est TLE of F-1 (updat­ed Sep 24, 2012)

We will try to pro­vide TLE as soon as pos­si­ble but ini­tial­ly you can use the ISS’s because F-1′s orbit will be very much sim­i­lar to that of the ISS.

1 25544U 98067A   12268.26025190  .00017277  00000-0  30696-3 0  3551
2 25544  51.6496 348.9327 0018454  95.4346 318.9373 15.50115148793411

2. Satel­lite pass pre­dic­tion

You can use any pro­gram to pre­dict satel­lite pass­es based on TLE. We sug­gest Orbi­tron v3.71 as it is quite sim­ple and easy to use
Note that you should syn­chro­nize your PC’s time by using Windows’s built-in fea­ture or by a 3rd par­ty tool such as Dimen­sion 4 v5.0

3. F-1 Teleme­try Decoder

- F-1 Teleme­try decoder requires Microsoft .Net frame­work 4.0 to run, if you haven’t installed the frame­work, you can down­load it from here .Net frame­work 4.0 
— F-1 Teleme­try Decoder v2.1.2 update 04/October/2012  (please unin­stall ear­li­er ver­sion first, if any)
— F-1 Teleme­try Decoder User Man­u­al (detailed instruc­tions)
Sam­ple audio
— Sam­ple audio F-1 PWM CW bea­con
— Sam­ple audio F-1 pack­et bea­con (this audio file con­tains a burst of 3 sim­i­lar teleme­try pack­ets from F-1, please use it to ver­i­fy that F-1 Teleme­try Decoder is run­ning cor­rect­ly on your com­put­er and ready to decode received pack­ets from F-1)

If your soft­ware modem only sup­port TCP/IP port:
-Please vis­it: and down­load, then instal­la­tion “ser­i­al port emu­la­tion dri­ver”.
-Down­load and Instal­la­tion TCP2COM
-Run your soft­ware modem.
-Run and con­fig TCP2COM soft­ware.
-Run F-1 Teleme­try Decoder.
4. F-1 bea­con data for­mat

4.1. VX-3R1
– Fre­quen­cy: 437.485MHz, FM Nar­row
– Pow­er sup­ply : direct­ly from solar cells, only oper­ates in sun­light
– Out­put pow­er: aver­age 0.2W, half-wave dipole anten­na
– Mod­u­la­tion scheme: Morse code bea­con (10 chars) using PWM CW
– Bea­con inter­val: every 90 sec­onds (con­fig­urable), each bea­con trans­mis­sion lasts about 20 sec­onds
– Bea­con pre­fix: there are 2 “z” char­ac­ters sent before the bea­con mes­sage, just ignore them
Bea­con for­mat:
No1 Data Descrip­tion Size (bits) Size (chars)
1 F-1’s call­sign XV1VN 5
2 OBC1 reset count Num­ber of OBC1 reset 8
3 Temp. 1 Tem­per­a­ture inside F-1, OBC board, oC 8  5
4 Temp. 2 Tem­per­a­ture out­side Y- side, oC 8
5 Check­sum bit 0 if sum of items #2 to #4 is even, 1 if it is odd 1
Total 10
- The bea­con data con­tain­ing 25 (8+8+8+1) bits stream is encod­ed into 5 Morse char­ac­ters using the fol­low­ing map­ping:
0 = 00000
1 = 00001
9 = 01001
A = 01010
B = 01011
V = 11111
- Since the UHF bea­con only has 0.2W out­put pow­er so it maybe dif­fi­cult to receive and decode the sig­nal. High gain Yagi anten­na (prefer­ably an array of yagis) is rec­om­mend­ed.

4.2 VX-3R2

– Fre­quen­cy: 145.980MHz , FM Nar­row
– Pow­er sup­ply: recharge­able bat­tery, oper­ates in the dark by default but can be com­mand­ed to oper­ate in sun­light as well
– Out­put pow­er: max 1.0W, half-wave dipole anten­na
– Mod­u­la­tion scheme: AFSK 1200bps
– Teleme­try inter­val: one burst of 3 teleme­try pack­ets in KISS for­mat every 30 sec­onds (con­fig­urable)
Teleme­try data for­mat:
No Data Descrip­tion Size (bit)
1 Date time Date: dd/mm/y: 5÷4÷3=12 bits
Time: hh/mm/ss: 5÷6÷6=17 bits
2 Bat­tery volt­age Bat­tery volt­age mul­ti­plied by 100 (divide by 100 to get actu­al val­ue) 11
3 Solar cells volt­age Solar cells volt­age mul­ti­plied by 10 (divide by 10 to get actu­al val­ue) 8
4 Temp. 1 oC (out­side Y+) 8
5 Temp. 2 oC (out­side Y-) 8
6 Temp. 3 oC (out­side X-) 8
7 Temp. 4 oC (out­side Z+) 8
8 Temp. 5 oC (out­side Z-) 8
9 Temp. 6 oC (out­side X+) 8
10 Temp. 7 oC (inside Z-) 8
11 Temp. 8 oC (inside, under VX-3R1) 8
Total 112 bits = 14 bytes


  • F-1 peri­od­i­cal­ly sends a burst of 3 teleme­try pack­ets with the same con­tent to avoid loss of pack­et
  • Time in UTC, 24 hours for­mat
  • Year count start­ing from 2012 (2012 equals 0, 2013 equals 1 and so on…)
  • Bat­tery volt­age read­ing is accu­rate to 0.01V, val­ues are mul­ti­plied by 100. Divide by 100 to get actu­al val­ue
  • Solar cells volt­age read­ing is accu­rate to 0.1V, val­ues are mul­ti­plied by 10. Divide by 10 to get actu­al val­ue
  • Tem­per­a­ture read­ing from sen­sors, will be added with 100 before trans­mis­sion to ensure a pos­i­tive num­ber so please sub­tract 100 to get actu­al val­ue
  • 112 bits, divide to 14 chunks of 8 bits, each chunk becomes one byte

5. Decod­ing data from F-1

For PWM CW bea­con, you can use your ear or any CW decod­ing tools you like, we sug­gest using CW Get (down­load from here
For teleme­try pack­ets, please use F-1 Teleme­try Decoder to decode, the soft­ware requires a COM port that is con­nect­ed to the TNC modem (a soft-modem such as MixW/virtual COM ports can also be used). You can use the client soft­ware to sub­mit decod­ed data to us or by send­ing direct­ly to me (via, audio records are high­ly appre­ci­at­ed. You will receive the ver­i­fi­ca­tion card from us!

Please feel free to ask if there is any ques­tion. We would real­ly appre­ci­ate your kind sup­port!


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