Tag Archives: UZ7HO

UZ7HO Sound-Modem 0.83b

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UZ7HO has updated his Sound-Modem software. The current version is 0.83b. Below a part of the latest changes.

SoundModem v0.83b changes:
- Added 12 dB PreEmphasis filter.
- Added 3 parallel decoders with NONE, 6 and 12 dB preemphasised signal.
  By default this option is ENABLED ("PreEmphasis filters - All" in "Modems"
  menu). On both (http://wa8lmf.net/TNCtest/) WA8LMF's Track1 and Track2 records
  1021 frames are decoded.
- Fixed some minor bugs.

Pre-emphasis

In processing electronic audio signals, pre-emphasis refers to a system process designed to increase (within a frequency band) the magnitude of some (usually higher) frequencies with respect to the magnitude of other (usually lower) frequencies in order to improve the overall signal-to-noise ratio by minimizing the adverse effects of such phenomena as attenuation distortion or saturation of recording media in subsequent parts of the system. The mirror operation is called de-emphasis, and the system as a whole is called emphasis.

Pre -De -Emphasis

Pre-emphasis is achieved with a pre-emphasis network which is essentially a calibrated filter. The frequency response is decided by special time constants. The cutoff frequency can be calculated from that value.

In high speed digital transmission, pre-emphasis is used to improve signal quality at the output of a data transmission. In transmitting signals at high data rates, the transmission medium may introduce distortions, so pre-emphasis is used to distort the transmitted signal to correct for this distortion. When done properly this produces a received signal which more closely resembles the original or desired signal, allowing the use of higher frequencies or producing fewer bit errors.

Source: Wikipedia

UZ7HO Sound-Modem update

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UZ7HO has again updated his Sound-Modem software. Below a part of the latest changes. With the current 2400 BPSK experiments on QB50p2 this version is a great improvement to decode these QP50p2 telemetry 2400 data.

High-Speed SoundModem v0.03b changes:
- Changed LPF filter in HAPN 4800 baud mode.
- Little code optimization.
- Fixed some minor bugs.

SoundModem v0.80b changes:
- Added new BPSK 2400 baud modem.
- Little code optimization.
- Fixed some minor bugs.

2400 baud BPSK QB50p2 IQ replay and the new Sound-Modem software
UZ7HO 2400 BPSK

UZ7HO Version overview:

SoundModem

  • AFSK 300, 600, 1200, 2400 baud.
  • (D)BPSK 300, 600, 1200, 2400 baud.
  • (D)QPSK 2400, 3600, 4800 baud.
 High-Speed SoundModem

  • G3RUH 9600, 19200 baud.
  • Manchester 1200, 2400, 3600, 7200 baud.
  • HAPN 4800 baud.

UZ7HO download page

GRIFEX active and decoded

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With the help of the recorded IQ file that can be downloaded at the following location, I was able to decode and send a couple of kiss packets to the GRIFEX telemetry server. Below you can see the data decoded by the MXL Ground Station Client.

GRIFEX-GS-client

2015-01-31 17:49:22.300 UTC: [267 Bytes KISS Frame (without CRC)]
   1 > C0 00 96 88 70 A6 A0 A6 60 86 A2 40 40 40 40 E1 03 F0 AB CD 
  21 > 00 00 00 42 03 F5 00 B4 75 16 10 00 00 00 00 1A 00 10 00 06 
  41 > 00 01 00 23 00 37 11 EE 7B C9 71 01 CA CB 00 00 7E 2A 00 00 
  61 > 12 00 1B 00 71 00 00 00 00 28 08 00 00 29 06 21 06 F9 0C 5D 
  81 > 00 27 00 F1 0C B8 0E 0C 00 A5 0E E3 05 47 06 B2 0E 0E 00 63 
 101 > 0D 1C 00 17 00 F9 0C 8B 00 54 00 14 06 63 0D 80 00 F6 0C AF 
 121 > 00 DB DD 00 0E 00 2F 02 0D 00 00 06 01 06 66 0A C4 00 03 0F 
 141 > 41 00 FB 05 FF 05 A8 00 02 00 2A 02 07 00 0D 06 0D 06 97 0A 
 161 > F3 00 2D 0F 53 00 05 06 09 06 01 FC 4E 06 4B 06 4F 06 00 DB 
 181 > DC 1E 00 5A 00 53 FF 65 00 C2 FF 12 00 99 00 AE FF 45 00 E8 
 201 > 00 F6 FF DB DD 00 4A 0B 40 0B 39 0A 27 0A 36 0A 41 0A BE 0A 
 221 > C4 0A 36 06 BE 09 03 00 00 00 88 33 88 33 4C 00 00 00 00 00 
 241 > 00 00 00 E3 03 00 00 01 00 FF FF FF FF FF FF FF FF FF FF FF 
 261 > 24 94 B0 15 1C 40 C0

UZ7HO-kiss-serverI used the UZ7HO G3RUH 1.7 beta sound modem software and enabled the Kiss server on port 9100. After that I configure the config.props file that is part of the MXL Ground Station Client software to use the kiss server port. Below the config.props I used.

Don’t use the tcp to serial option that comes with the GS client software. There is a direct connection between the GS client and UZ7HO via in my example port 9100.

radio.1.name=Radio
radio.1.address=localhost
radio.1.port=9100
radio.1.type=KISS
radio.1.tncport=1

client.callsign=PE0SAT
client.id=PE0SAT_GS
server.address=mxlab.engin.umich.edu
server.port=12805

librap.SID=50
librap.PID=0

api.crafts=https://mxl-ops.engin.umich.edu/api/craft?count=25
api.command=https://mxl-ops.engin.umich.edu/api/commands/
api.raps=https://mxl-ops.engin.umich.edu/api/raps

Good luck decoding GRIFEX with this setup.

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