Amateur satellites

Amateur satellites (AMSATs)

This page deals with my experience of the following amsats as they were in approximately 1998:


The Radiosport or RS series of Russian satellites characteristically have, like Rs-13 did, a downlink frequency in the 29 MHz amateur band, and uplink frequencies in either or both the 2 metre band and the 21 MHz band. Usually they have a Robot auto responder to messages sent in CW (Morse code).

In November 1996 satellite RS-10 was transpoding the signals it heard on the Robot uplink frequency down onto the 10m robot beacon without responding to them - this happened when the meemory filled up. In an experiment using the satellite travelling Northbound I sent CW to the transponder and listened for my own signal on its downlink frequency. This was basically an experiment showing the doppler effect because the satellite receiver had only a 2 kHz bandwidth around 145.820 MHz.

The graph below shows that the signal was relayed from the moment of the Acquistion of Signal (AOS) until after it had flown by (AOS +9 minutes) when my transmitting frequency had to move higher in order to get into the receiver bandwith.


RS-13 is usually in mode KA, that is, the uplink (ground-to-satellite) is both 21 MHz and 144 MHz and the downlink is 28 MHz. I use my HF transceiver, SSB voice, to uplink on 21 MHz. The map below shows contacts I have made via this satellite, covering an area from the Canary Islands to Sweden.


Boxing day, 1994, and I just happened to be listening on the published beacon frequency around 29 MHz when the the frequency suddenly came to life. Aside from the usual Morse code telemetry, a sudden burst of data... Ground control Moscow later confirmed this by email:


TO: andrew thomas, 70374,440

DATE: 12/29/94 at 13:37

SUBJECT: Thanks!


Received: from by (8.6.9/5.940406sam)

id IAA25693; Thu, 29 Dec 1994 08:33:05 -0500

Received: from by with UUCP id QAA04049;

(8.6.9/D) Thu, 29 Dec 1994 16:23:32 +0300

Received: by; Thu, 29 Dec 1994 16:21:30 +0300

Received: by; Thu, 29 Dec 1994 16:17:41 +0300

Received: by; Thu, 29 Dec 94 01:35:36 +0300

Date: Thu, 29 Dec 94 01:35:35 +0300

Message-Id: <>

From: (Leo Maksakov)

Subject: Thanks!


X-Mailer: ITS [version 1.2]

Dear Andrew Thomas, Thank you very much for your RS-15 Observations report and for your congratulations to RS-group. You noted:

> ... signal interrupted at 1138 with ?data tx...

Yes. You absolutely right. That's RS3A had read telemery data on computer.

Our Congratulations, Best Wishes and Happy New Year with RS15!

73, RS-group.

Sputnik-40 and Sputnik-41 (hand-launched from Mir)

Sputnik-40 was a small satellite hand-launched by Mir in 1997, to commemorate the 40th anniverary of Sputnik. It was followed by Sputnik-41 in 1998. Although the frequency of Sutnik-40's "bleep-bleep" did not change, part of the sequence of transmission from Sputnik-41 included a tone which varied according to the temperature, and so various methods were dreamt up to measure frequency exactly. The image below is fast-fourier analysis of the received signal from Sputnik-40, showing a received frequency of 1260 Hz. Recordings from Sputnik-41 showed a frequency varying between 1194,5 to 1263 Hz, indicating a temperature between about 18 and 25 degrees Celsius at the time of the observation.





DOVE (DO-17) sent AX-25 data packets down on 145.825 MHz NFM, which when decoded gave information about the internal state of the satellite. Projects could look at the relation of temperature to battery voltage etc. This is a sample file captured from DOVE on 8 December 1996. Sadly DOVE is no longer functioning.


--------------- DOVE-1 Satellite Telemetry Analysis By KD2BD --------------

DOVE-1/OSCAR-17 Raw Telemetry:


00:58 01:58 02:88 03:34 04:58 05:58 06:6F 07:50 08:6E 09:6B 0A:A0

0B:FF 0C:E9 0D:DB 0E:34 0F:26 10:DB 11:9B 12:00 13:E1 14:AB 15:AA

16:6F 17:76 18:76 19:7A 1A:76 1B:4F 1C:7B 1D:78 1E:D6 1F:63 20:D3


21:BD 22:74 23:2F 24:1F 25:38 26:2D 27:00 28:46 29:00 2A:00 2B:57

2C:02 2D:8C 2E:66 2F:9D 30:C6 31:96 32:00 33:00 34:A1 35:A9 36:AA

37:AC 38:A7

DOVE-1/OSCAR-17 Decoded Telemetry:

[00] Rx E/F Audio (W) 2.16 V(p-p)

[01] Rx E/F Audio (N) 2.16 V(p-p)

[02] Mixer Bias V 1.39 Volts

[03] Osc. Bias V 0.53 Volts

[04] Rx A Audio (W) 2.16 V(p-p)

[05] Rx A Audio (N) 2.16 V(p-p)

[06] Rx A DISC 0.13 KHz

[07] Rx A S Meter 80.00 Counts

[08] Rx E/F DISC -1.28 KHz

[09] Rx E/F S Meter 107.00 Counts

[10] +5 Volt Bus 4.88 Volts

[11] +5V Rx Current 25.50 mA

[12] +2.5V VREF 2.52 Volts

[13] +8.5V Bus 8.56 Volts

[14] IR Detector 52.00 Counts

[15] LO Monitor I 1.41 mA

[16] +10V Bus 11.11 Volts

[17] GaAs FET Bias I 4.03 mA

[18] Ground REF 0.00 Volts

[19] +Z Array V 23.02 Volts

[20] Rx Temp -2.42 Deg. C

[21] +X (RX) Temp -1.82 Deg. C

[22] Battery 1 V 1.41 Volts

[23] Battery 2 V 1.38 Volts

[24] Battery 3 V 1.38 Volts

[25] Battery 4 V 1.36 Volts

[26] Battery 5 V 1.39 Volts

[27] Battery 6 V 1.53 Volts

[28] Battery 7 V 1.39 Volts

[29] Battery 8 V 1.38 Volts

[30] Array Voltage 22.61 Volts

[31] +5V Bus 5.02 Volts

[32] +8.5V Bus 8.92 Volts

[33] +10V Bus 11.58 Volts

[34] BCR Set Point 125.68 Counts

[35] BCR Load Curr 240.96 mA

[36] 8.5V Bus Curr 49.67 mA

[37] +5V Bus Curr 246.38 mA

[38] -X Array Curr 86.00 mA

[39] +X Array Curr -13.49 mA

[40] -Y Array Curr 155.34 mA

[41] +Y Array Curr -11.41 mA

[42] -Z Array Curr -16.53 mA

[43] +Z Array Curr 186.99 mA

[44] Ext Power Curr -15.00 mA

[45] BCR Input Curr 505.02 mA

[46] BCR Output Curr 334.66 mA

[47] Bat 1 Temp 6.05 Deg. C

[48] Bat 2 Temp -18.76 Deg. C

[49] Baseplate Temp 10.29 Deg. C

[50] FM TX#1 RF Out 0.03 Watts

[51] FM TX#2 RF Out -0.00 Watts

[52] PSK TX HPA Temp 3.63 Deg. C

[53] +Y Array Temp -1.21 Deg. C

[54] RC PSK HPA Temp -1.82 Deg. C

[55] RC PSK BP Temp -3.03 Deg. C

[56] +Z Array Temp -0.00 Deg. C