A small correction:
When I wrote destination callsign, I meant source (or digipeater) callsign.
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 9:51 PM, Edson W. R. Pereira ewpereira@gmail.com wrote:
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) < the2belo@msd.biglobe.ne.jp> wrote:
On Thu, 21 Apr 2016 17:43:36 -0500, "JoAnne Maenpaa" k9jkm@comcast.net 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 the2belo@msd.biglobe.ne.jp http://www.flickr.com/photos/the2belo/ http://www.qrz.com/db/JR2TTS Twitter: @Minus2_C
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