Author Archives: PE0SAT

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

Send STRaND-1 Kiss files

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STRaND-1Dr. Chris Bridges (M0GKK) has requested that the ground stations that receive STRaND-1 telemetry to send there .kss files to strand.messages [at] gmail.com

The following combination works great when you want to receive and decode the telemetry data: FUNcube Dongle Pro+, SDRSharp 1144, RealTec Audio Mixer, UZ7HO G3RUH Soundmodem and AGW OnlineKiss from DK3WN. The software can be downloaded at the following locations:

I don’t have any hands-on experience with it, but I can imagine that a RTL-SDR dongle will also work when someone wants to receive the telemetry data from STRaND-1. If you don’t have any experience with Sound card modem reception take a look at my Sound card modem page.

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

Amsat-UK Space Colloquium Webcast

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AMSAT-UK LogoI would love to visit the Amsat-UK Colloquium but I am unable to. Therefor the Webcast that is made possible by the volunteers from BATC gives me the second best possibility to follow this Amsat-UK event.

So if you can’t get to Guildford then the webcast provides the next best thing.

Watch live via this link. (view stream AMSAT 2013)

The schedule, times in BST (GMT+1), is at Colloquium 2013 Schedule

Homepage and other references:

Amsat-UK Colloquium 2013 information.