Category Archives: Decode

Satellite decoding information

New SDR# DDE plugin

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There is a new SDR# DDETracker plugin.

Ian Gilmour (MM6DOS) has created an add-on to the excellent SDR# program which allows DDE compatible software to control the receive frequency in SDR# Required for best results to correct for the Doppler shift when working with satellites with for example: WXTrack, SatPC32 and Orbitron.

SDR DDETracker

The new version now also supports mode setting. I use this version in combination with SatPC32 and works great. Download the plugin via his website, copy two dll files and add the following to you SDRSharp.exe.Config file. (Newer SDR# version – Plugins.xml)

<add key="DDE Tracker" value="SDRSharp.DDETracker.DdeTrackingPlugin,SDRSharp.DDETracker" />

SDR# DDE Plugin: DDETracker (Version 5 beta: DDETracker V5 beta Binaries)

Update: 04-01-2014

The combination that is working for me, is SDR# Nightly build, the V5 beta binaries from Ian and SatPC32 V.12.8c. When talking to PA3GUO we found out that the current stable version (Rev 1000) isn’t working. When using SatPC32 the DDE interface is configured via the DivOptions.SQF file and I use the following settings:

- (1)
+ (2)
+ (3)
- (4)
- (5)
;
; Hints
;
; The  +/- signs in lines 1,2,3,4 and 5 allow manual changes of program
; options whiche cannot be done in the menu 'Setup' and its sub menus. 
;
; Don't forget to save possible changes, please!  
; All changes require a program re-start to take effect. 
;
; Line #1: Rotor and CAT steering functions
           +: are available in a 2nd program instance,
;          -: are not available in a 2nd instance (default),
; Line #2: The "general" DDE interface will output data
,          +: constantly, 
;          -: only when the satellites elevation is > 0 (default),
; Line #3: Frequency values sent by the DDE interface
;          +: do not include converter/transverter offsets (default),
;          -: include converter/transverter offsets, 
; Line #4: SatPC32 steers
;          +: only the Downlink frequency and mode,
;          -: Downlink and Uplink frequencies and modes (default)
;
; Line #5: Auxiliary files will be opened with
;          -: Notepad (default).                    
;          +: the build-in editor.

Delfi-C3 Telemetry 18-08-2013

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Delfi-C3 (DO-64) Telemetry 18-08-2013 19:30 UTC

All those carriers around the receive frequency make it difficult to decode some telemetry data, but this evening we could receive about 150 frames.

DO-64 18-08-2013 19:30UTC

Lets see what information is available from those frames. Nice to see that this Satellite that is already 1938 Days in space is still sending so many frames after every reboot.

DO-64 18-08-2013 19:30UTC

Delfispace main website: Delfispace

STRaND-1 Telemetry 04-08-2013

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STRaND-1 04-08-2013 18:03 UTC

Here is an image from the orbit that STRaND-1 had during this pass. AOS was in the North-East and LOS almost due South. I am puzzled why STRaND-1 is sometimes much stronger when switching to LHCP. This was such a pass and in the images below you can see the difference.

STRaND-1 SatPC32 04-08-2013 18:03UTC

Date and Time: 04-08-2013 18:03 - 18:17 UTC
Object       : STRAND 1
Max elevation: 54 degree
Azimuth      : 018 - 184 degree
Polarization : LHCP Strongest
Signal       : max 30 dB above noise
Frequency    : 437.568000 MHz FM +/- doppler
Status       : Active
Remark       : LHCP much stronger then RHCP, 518 Frames

Kiss file: STRaND-1_04082013_1754.kss

Signal difference between LHCP and RHCP in the beginning of the pass. You can see the difference when I switch between LHCP and RHCP.

STRaND-1 SDR 04-08-2013 18:03UTC-01

Further in the pass and closer as you can see in the signal strength. And again a big difference in signal strength when switching between LHCP and RHCP.

STRaND-1 SDR 04-08-2013 18:03UTC-02

The last image, is the decoded data from the frames that I received during this pass. It looks that the solar panels on the +Y array are producing the largest amount of power. Does this tell something about the fact that signals are stronger when using LHCP.

STRaND-1 DK3WN 04-08-2013 18:03UTC

STRaND-1 Telemetry 31-07-2013

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STRaND-1 31-07-2013 18:37 UTC 937 Frames in one pass.

SDR# Spectrum, as you can see very strong signals from this Cubesat.

STRaND-1 31-07-2013 18:37UTC

Date and Time: 31-07-2013 18:37 - 18:51 UTC
Object       : STRAND 1
Max elevation: 77 degree
Azimuth      : 014 - 200 degree
Polarization : RHCP Strongest
Signal       : max 40 dB above noise
Frequency    : 437.568000 MHz FM +/- doppler
Status       : Active
Remark       : 937 Frames

Kiss file: STRaND-1_31072013_1731.kss

Decoded the data with the software decoder from DK3WN.

STRaND-1 TLM 31-07-2013 18:37UTC

ESTCube-1 Telemetry

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ESTCube-1 has started downloading a new image that it has taken with the onboard camera. I’m going to try once again to decode the image data. One of the problems I face, is a strong local generated carrier on 437.495 that makes it impossible for me to decode all the data during a pass.

ESTCube-1 29-07-2013 11:35UTC

There is a new decoder version that is also able to generate the image. Take a look at the software page from Mike DK3WN. (estcube_fm.zip)

Information about my latest pass:

Date and Time: 29-07-2013 11:35 - 11:47 UTC
Object       : ESTCUBE-1 - 13021C
Max elevation: 46 degree
Azimuth      : 008 - 213 degree
Polarization : LHCP Because of the carrier at 437.495
Signal       : max 25 dB above noise
Frequency    : 437.505000 MHz FM +/- Doppler
Status       : Active
Remark       : Interference from a local generated carrier

Kiss file generated between 08:24 – 11:47 UTC: ESTCube-1_29072013_0752.kss

STRaND-1 is Back

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Dr Chris Bridges with STRaND hardwareJust last weekend at the Amsat-UK Collegium, I heard Dr. Chris Bridges say that it would probably be November before we would hear STRaND-1 again, in that period the satellite would go in eclipse causing the system to reset.

But and you may have heard it already, from Tuesday July 23 2013 the satellite is transmitting again and a lot of ground stations are collecting data from the little 3U Cubesat. Maybe now, when the satellite becomes stable, the smartphone experiments can begin.

Below is a SDRSharp spectrum from the signals that I received in the evening on the 23 of July 2013. During that first pass I already collected 96 frames where the max. elevation was 05 degree.

STRaND-1 TLM 23-07-2013 21:26 UTC

After that evening I tried to download as much telemetry as possible with for me a new record on Thursday evening of more then 1200 frames in three passes. But there was something strange when I used the STRaND-1 telemetry decoder made by Mike DK3WN. When I took my kiss file and used it with the decoder there was no OBC beacon data visible. After I had a word with Mike he told me to use Soundmodem from UZ7HO because the MixW packet decoder is dropping all frames that are shorter than 15 bytes. And indeed, now with another 9600 baud G3RUH decoder all frames are visible, even the smaller ones.

Here is an example of a 14 and 20 bytes frame:

2013-07-26 18:14:47.020 UTC: [14 Bytes KISS Frame (without CRC)]
   1 > C0 00 DB DC 80 A5 06 02 2D 1F 02 FF 03 C0 
   À.ÛÜ€¥..-..ÿ.À
2013-07-26 18:14:48.030 UTC: [20 Bytes KISS Frame (without CRC)]
   1 > C0 00 DB DC 80 A6 0C 02 89 05 08 A2 18 FF FF 88 B4 03 00 C0 
  21 > 
  À.ÛÜ€¦..‰..¢.ÿÿˆ´..À

Now, at same time as I am writing this article there are already 860 frames received with the UZ7HO Soundmodem software during the first two passes of this evening. The signals are strong, at moments they are 25 – 30 dB above noise.

After feeding these over 800 frames in to the decoder software, it produces the following output.

STRaND-1 TLM 26-07-2013 16:27 UTC

After the following three passes I have received 1371 frames using a FUNcube Dongle Pro+, SDRSharp 1144, RealTec Audio Mixer, UZ7HO G3RUH Soundmodem and AGW OnlineKiss from DK3WN.

26.07.2013 STRaND-1 16:27 - 16:36 UTC
26.07.2013 STRaND-1 18:05 - 18:19 UTC
26.07.2013 STRaND-1 19:45 - 19:57 UTC

If you want to use the kiss file, you can download it at the following location:STRaND-1_26072013_1620UTC.kss