7 votes
Accepted

Using Direwolf with multiple radios?

I've put together something that is conceptually similar to @user3486184's comment, but without actually using chroot. I'm taking advantage of SystemD to manage ...
larsks's user avatar
  • 608
6 votes
Accepted

What exactly are Gold sequences and how are they used?

Table of contents But what exactly generally is a Gold code? How exactly are they implemented in order to differentiate multiple signals on the same frequency? What Gold Codes are and aren't How ...
Marcus Müller's user avatar
6 votes
Accepted

Is there a difference between AFSK and FSK for AX.25/APRS USE?

My reading suggests that the advantage of AFSK is that the audio signal can be fed to any radio mike input. But if we ignore that, and assume a transmitter where the frequency can be controlled ...
Kevin Reid AG6YO's user avatar
  • 24.5k
5 votes

Is there a difference between AFSK and FSK for AX.25/APRS USE?

AFSK sent over a FM radio is very different to FSK, as explained in my blog post FM over FSK: FSK over FM is not FSK when you look at the over the air waveform. The spectrum is no longer two tones ...
David Rowe's user avatar
5 votes

AX.25 on macOS (aside from APRS)

Xastir isn't bad at all but I recently encountered something called YAAC (Yet Another APRS Client). On it's site it states the following: YAAC can be used as a stand-alone APRS client, an APRS RF-...
Tmanok's user avatar
  • 161
3 votes
Accepted

ax.25 error shown in direwolf. Fails on channel 8, then 2, then works

This is issue #42 on Direwolf's GitHub page. https://github.com/wb2osz/direwolf/issues/42 To work around it, put the interface into CRC mode "none" with a command like this: ...
Mike Playle's user avatar
2 votes

Cannot establish AX.25 connection to RMS gateway

Is it possible that my VOX has a hang time that's causing me to loose the initial response to my call? Yes, that is definitely possible. You want the lowest possible VOX threshold and, if possible, ...
anarcat's user avatar
  • 125
2 votes

GFSK Demodulationsoftware

I managed to solve the problem. Basically I implemented the DSP demodulation software in GNU Radio. I then rewrote AX.25 software stack in C++. It is not a very complicated stack and it didnt take a ...
Moses Browne Mwakyanjala's user avatar
2 votes

Is there a difference between AFSK and FSK for AX.25/APRS USE?

FSK is a modulation where the instantaneous frequency corresponds to a binary baseband signal. Given: $x_m(t)$ is the baseband signal, perhaps a binary square wave taking values of -1 and 1, $f_c$ is ...
Phil Frost - W8II's user avatar
2 votes

Cannot transmit with direwolf ("Audio output start error")

So...I have a solution, but not an explanation. The original configuration was specifying the sound card as plughw:4,0. As I mentioned in the question, this worked ...
larsks's user avatar
  • 608
2 votes

What exactly are Gold sequences and how are they used?

To quote the Wikipedia article: A Gold code, also known as Gold sequence, is a type of binary sequence, used in telecommunication (CDMA) and satellite navigation (GPS). Gold codes are named after ...
natevw - AF7TB's user avatar
2 votes
Accepted

How do you open ax.25 ports?

Listen tcp 0.0.0.0:5000 bind address already in use. This sounds like a somewhat generic error, not necessarily related to your AX.25 software itself but certainly a bummer to encounter it while ...
natevw - AF7TB's user avatar
2 votes

nrparms: SIOCADDRT: Inappropriate ioctl for device

Looking at the kernel code, I see four things that can make an "add node" ioctl on a netrom socket return -EINVAL: The route has more than 8 digipeaters. ...
hobbs - KC2G's user avatar
  • 12.4k
1 vote

Use Direwolf for ax.25 connections w/o kernel support?

Sort of, yes, if you have userspace programs that speak AGWPE or KISS rather than trying to create their own kernel ax25 sockets. KISS is basically just an encapsulation for raw AX.25 packets, so a ...
hobbs - KC2G's user avatar
  • 12.4k
1 vote
Accepted

Cancel beacon on AX.25 Linux Stack

Use beacon killall. This will kill all your beacons if you have more than one. If you want to keep one of several beacons, you will have to restart them manually. ...
Joshua's user avatar
  • 61
1 vote

What value goes in the AX.25 PID field if the Layer 3 protocol is not defined in the standard?

The AX.25 Amateur Packet Radio Link-Layer Protocol Version 2.0 October 1984 document states: "All forms of yy11yyyy and yy00yyyy other than those listed above are reserved at this time for ...
John's user avatar
  • 156
1 vote

ax.25 error shown in direwolf. Fails on channel 8, then 2, then works

this is not a direwolf issue. this is an issue with the ax0 N_KISS line dicipline for tty/pty's of the linux kernel. indeed. first packet -after you bring an ax0 interface up- has KISS control byte 80 ...
HRH Sven Olaf of CyberBunker's user avatar
1 vote

AX25 + Reed Solomon : Bit stuffing errors

I'm quite confused by your question. I suspect you are talking about a satellite which is using the FX.25 protocol (on Wikipedia), which is an extension of the original AX.25 protocol. FX.25 is a ...
jcoppens's user avatar
  • 699
1 vote
Accepted

GFSK Demodulationsoftware

This is a bit cobbled together, but sometimes that's the only way to get things done! http://www.pe0sat.vgnet.nl/decoding/unix-tlm-decoding Part of this article refers to Dirweolf, a packet AX.25 ...
guitarpicva's user avatar

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