Hi Jeff,

Here some extra info that might help:

Use BPSK AX.25 mode when decoding QB50p1, make sure non-AX25 filter is not selected. You can try to replay the file at: http://janvgils.home.xs4all.nl/download/QB50px/ to see if things are working. There three different signals in the file.

QB50p1 1200bps and 2400 bps DO-64 (Delfi-C3) with 1200bps

They can both be decoded with UZ7HO and AGW Online Kiss.

Maybe the block diagram on the following page will also help in understanding how things can be connected. http://www.pe0sat.vgnet.nl/decoding/block-diagram/

73 Jan - PE0SAT

On 21-04-2016 18:33, Mike Rupprecht wrote:

Hi Jeff,

if you use soundmodem by UZ7HO you don't need AGW Packet Engine.

Firstly start soundmodem software, then AGW Online KISS OR use the QB50p1 Online decoder. If it's connected you should see a green light.

If you successfully decode a packet you should see something like this in soundmodem:

2: <NON-AX25 frame Len=125> [18:29:19R] 2: <NON-AX25 frame Len=125> [18:29:29R] 2: <NON-AX25 frame Len=125> [18:29:39R] 2: <NON-AX25 frame Len=125> [18:29:49R]

73 Mike DK3WN

-----Ursprüngliche Nachricht----- Von: AMSAT-BB [mailto:[email protected]] Im Auftrag von Jeff A. Boyd Gesendet: 21 April 2016 17:18 An: [email protected] Betreff: [amsat-bb] Need help decoding EO-79 packets.

I have been trying for weeks to set up a system to decode telemetry packets from EO-79 (QB50P1) without success. As I am new at dealing with data from satellites that is not already handled by a dedicated program such as FUNCube Dashboard, which handles Doppler tracking and packet decoding all by itself, I'm still kind of lost as to how all the required components are supposed to come together.

If I can figure out EO-79, goes my thinking, then I can go on to tackling other BPSK 1200 baud birds such as the XW-2 constellation. I will list what I'm doing below; if someone can please give me a sanity check it would be greatly appreciated.

• Receiver: FUNCube Dongle Pro+, SDR# outputting to a virtual audio

cable.

• SATPC32 tracking EO-79, correcting for Doppler, and controlling

SDR#.

• AGW Packet Engine set up with "Sound Card" TNC (the other end of the

virtual audio cable), dual port, 1200 baud for each channel.

• AGW Online KISS set up to connect to the Packet Engine. WINSock

remote port 8000.

• Soundmodem by UZ7HO on the same port 8000 and listening to SDR#,

which is set for USB, 4kHz bandwidth. SATPC32 is keeping the packet traces in the center of the 4kHz passband, and I can see the traces appearing in the waterfall in Soundmodem. The modems in Soundmodem (2 channels) are set for BPSK 1200 baud, and the reticules match up exactly with the traces I can see in the waterfall.

And Soundmodem refuses to decode a single #$%&ing thing. There is an occasional "<NON AX.25 FRAME>" that shows up in the list, and Online KISS will show a bunch of garbage, but this mostly occurs when there is nothing in the waterfall at all.

Several sites have said that I'm to connect something to something else using virtual serial ports, but none of them have really given me a straight answer as to where to connect what to what.

What am I doing wrong here? Any advice would be ridiculously appreciated.

73

-- J. Boyd, JR2TTS/NI3B [email protected] http://www.flickr.com/photos/the2belo/ http://www.qrz.com/db/JR2TTS Twitter: @Minus2_C

There were some other things in my Soundmodem settings that did not agree with the instructions for DeorbitSail, that may have messed it up, so I'll try again this morning during the next pass.

I'm continuing to experiment by myself on this subject of receiving telemetry data using an SDR dongle and software. I've appreciated all the bits of information offered by the stations who are already up and running.

One thing I'm finding with software packet reception is that the software "modem" or software "TNC" (i.e.: soundmodem) seems to expect packets with a good checksum. Just a single bit-flip and I don't have data.

My approach at the moment is toward improving my downlink and then I'll see how many more packets I'll find useful.

-- 73 de JoAnne K9JKM [email protected]

The AX.25 implementations used in some cubesats do not implement the specs for AX.25 destination address field encoding correctly. The last bit of the last byte of the destination callsing (or digipeater) field should always be 1 in order to indicate the end of the destination field, but some implementations keep the bit as 0. This is the reason UZ7HO's soundmodem says NON-AX25 frame. Soundmodem does pass the frame to the KISS interface but any decoding software must be careful during the processing of the destination callsign (by assuming there are no digipeaters).

Comparing the performance of the 1200 bps BPSK FUNcube-1 FEC encoding with cubesats using AX.25 1200 bps BPSK makes me wander why in this day and age we still use AX.25 for satellite links.

73, Edson PY2SDR

--- - We humans have the capability to do amazing things if we work together. - Nós seres humanos temos a capacidade de fazer coisas incríveis se trabalharmos juntos.

On Thu, Apr 21, 2016 at 7:56 PM, J. Boyd (JR2TTS) < [email protected]> wrote:

On Thu, 21 Apr 2016 17:43:36 -0500, "JoAnne Maenpaa" [email protected] wrote:

...

...

There were some other things in my Soundmodem settings that did not agree with the instructions for DeorbitSail, that may have messed it

up,

...

...

so I'll try again this morning during the next pass.

I'm continuing to experiment by myself on this subject of receiving telemetry data using an SDR dongle and software. I've appreciated all the bits of information offered by the stations who are already up and

running.

...

One thing I'm finding with software packet reception is that the software "modem" or software "TNC" (i.e.: soundmodem) seems to expect packets

with a

...

good checksum. Just a single bit-flip and I don't have data.

In soundmodem, I had "Bits Recovery" set to "SINGLE" initially, while the DeorbitSail page seems to suggest it's more properly set to "NONE". Not sure if that's significant, but your comment about flipped bits made me suspect this. Anything's worth trying once.

-- J. Boyd, JR2TTS/NI3B [email protected] http://www.flickr.com/photos/the2belo/ http://www.qrz.com/db/JR2TTS Twitter: @Minus2_C

---

Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb

On Thu, 21 Apr 2016 18:56:15 +0200, PE0SAT | Amateur Radio [email protected] wrote:

Hi Jeff,

Here some extra info that might help:

Use BPSK AX.25 mode when decoding QB50p1, make sure non-AX25 filter is not selected.

Update: I'm looking at a pass right now, and am getting a signal, but Soundmodem is just refusing to budge. Maybe the signal just isn't strong enough?

http://i.imgur.com/PbN64Jb.png

Hi Jeff,

I will give your IQ recording a try.

Regards Jan PE0SAT

On 23-04-2016 17:41, Jeff A. Boyd wrote:

On Thu, 21 Apr 2016 18:56:15 +0200, PE0SAT | Amateur Radio [email protected] wrote:

...

You can try to replay the file at: http://janvgils.home.xs4all.nl/download/QB50px/ to see if things are working.

Hello,

Here's a follow-up to my ongoing struggle to grab this bird. I downloaded the above file and ran it in SDR# and confirmed that Soundmodem was seeing it fine -- it decoded the 1200 baud BPSK and sent it to AGW Online Kiss. I saw KISS frames scrolling up the console like gangbusters. No problems there.

So tonight I sat down and recorded a full QB50p1 (EO-79) pass with this same configuration, 1200 baud BPSK. I saw the trace in the waterfall, and saw the little "Ch. A" light come on when the trace went past the reticule.

But no data. I could not pull a single packet out of it.

I recorded the entire pass' I&Q and have put it up on my Dropbox in case anyone would be kind enough to run it and tell me if the signal is simply too weak to get any data out of.

https://www.dropbox.com/s/11s972ylbfhkt2g/QB50p1-PM85jl-20160423_1443UTC_1k2...

For reference, the antenna used is a VHF/UHF discone.If the answer is simply "signal too weak, you need more gain", then at least I'd be making some progress in understanding it. Certainly *looked* strong enough.

Tnx es 73

On Sat, 23 Apr 2016 18:06:27 +0200, PE0SAT | Amateur Radio [email protected] wrote:

Hi Jeff,

Signal to noise isn't good enough. So yes the signal is to weak.

Okay at least I know it's not my setup, just my signal. How close do you think I am from looking at the recording? Would a preamp help me here or am I going to have to go out at midnight and point a yagi at it? :)

On Thu, 21 Apr 2016 18:33:09 +0200, "Mike Rupprecht" [email protected] wrote:

If you successfully decode a packet you should see something like this in soundmodem:

2: <NON-AX25 frame Len=125> [18:29:19R] 2: <NON-AX25 frame Len=125> [18:29:29R] 2: <NON-AX25 frame Len=125> [18:29:39R] 2: <NON-AX25 frame Len=125> [18:29:49R]

I saw some of these appear, with varying length values, but they appeared when there was no actual signal. When I actually fed it a signal, it didn't respond. So perhaps I've got Soundmodem set wrong. Non-AX25 filter is off, but maybe it's something else.

I've looked at the DeorbitSail page so I'll see if my settings match what's there. Thanks! Will report back.