5 ms·

AMPKT – Amateur radio packet explorer

49 points by hexagonal-sun 3y ago

hexagonal-sun 3y ago
This is a project to connect two Linux machine's network stacks via the amateur radio bands. It uses Linux's TAP interface to read & write packets at layer 2 to/from the kernel. QPSK modulation is used at the RF layer. For now experimentation has mainly been done in a Ramsey box. The next step is to add a callsign field to the QPSK frames so the data can be legally TX'd.
- drmpeg 3y ago
  You'll like my IP over DVB-T2 test bed using GNU Radio. It uses the ULE protocol dvbnet driver that's built into Linux. Not shown on the diagram is that it also supports IPv6. https://www.w6rz.net/ofdm3.png https://www.w6rz.net/ofdm3.png
lobsterslive 3y ago
If anyone is looking for a really good place to get started with SDR, I'd highly recommend the RTL-SDR Blog V3: https://www.amazon.com/gp/product/B0BMKB3L47 https://www.amazon.com/gp/product/B0BMKB3L47
- cogman10 3y ago
  Dumb question (and maybe this isn't legal?) but are there SDR transceivers/libraries? It'd be neat to have a zigbee/zwave hub with my SDR so I could mix and match some stuff.
  - cadr 3y ago
    HackRF One is an option. There are a number of others. Legality varies by country/frequency/power level. Can also make a Raspberry Pi act as a transmitter (https://github.com/F5OEO/rpitx https://github.com/F5OEO/rpitx), which could hit the zwave frequency but not the zigbee one. (Also, make sure to put a low pass filter on it.)
    - wkat4242 3y ago
      Or even better, a band pass. The output from that pin is really dirty. I wouldn't recommend it for anything that will actually transmit into an antenna. Even with filters.
  - mwbajor 3y ago
    Gnuradio
  - _whiteCaps_ 3y ago
    Yup, lots around. The hint is to look for 'full duplex' SDR.
  - ajsnigrutin 3y ago
    Doing zigbee or zwave stuff is a lot easier with zigbee and zwave than with SDR. Just use homeassistant with something like zigbee2mqtt, and you can control your LIDL light with an Ikea light switch and xiaomi movement sensor without any issues.
kunwon1 3y ago
I recently got back into amateur radio with an SDR (listening only, my license has lapsed and I need to renew it) I found that using the FT8 protocol, I can pick up transmissions from up to ~6000 miles away, using a very cheap magnetic loop antenna mounted indoors in my apartment. My building is made of concrete slabs and I was pretty shocked that I was able to receive such distant transmissions. I think I've invested maybe $70 into radio equipment for this capability. I've listened to a lot of other signal sources, but so far FT8 is the most interesting. I can run a companion app that maps out all the contacts, it is pleasing to watch on a nice slow evening
- bmitch2112 3y ago
  FT8 is lots of fun. Even more fun when you go to a park or up a summit and see how far you can get out and how far you can hear. You don't need very expensive radio equipment to transmit FT8 so if you do get your licence back it is worth looking into. http://qrp-labs.com/qdx.html http://qrp-labs.com/qdx.html
  - lhamil64 3y ago
    I got my license about a month ago and ordered a QDX to try FT8, but they're super back-ordered. The orders page shows that they're just now fulfilling orders from May.
    - bmitch2112 3y ago
      Do you have another radio to try it with? Another cheap option is the truSDX https://dl2man.de/ https://dl2man.de/ I have it working with my Android Phone using https://github.com/N0BOY/FT8CN https://github.com/N0BOY/FT8CN It makes for a super lightweight pack. I usually bring a 17foot whip antenna to a park or summit and get contacts all over the world.
      - lhamil64 3y ago
        No I don't, do you know if you can buy the truSDX pre-assembled, or does it just come in a kit? I'm visually impaired, so soldering is difficult for me. But I'd like to try getting on HF.
mzerod 3y ago
I have a QPSK & BPSK packet radio link to several other stations via the QO-100 satellite narrowband transponder, using a couple of Pluto SDRs and in some cases a mix/match of RTL SDR dongles and 70cm radios with transverters. Only a small group (4 so far) doing it, but we can be heard on the WEBSDR hosted at Goonhilly Earth station[1] Due to small dish sizes on RX (10GHz) we are keeping it simple and open at 1200 BPSK and QPSK 2400 with IL2P[2][3] for FEC+RS robustness, and not even close to the 2.7Khz max permitted bandwidth. [1] https://eshail.batc.org.uk/nb/ https://eshail.batc.org.uk/nb/ - 10489630 USB [2] https://tarpn.net/t/il2p/il2p.html https://tarpn.net/t/il2p/il2p.html [3] https://eindhoven.space/il2p https://eindhoven.space/il2p
- sidewndr46 3y ago
  This is very cool. I wish those of us in North America had access to a satellite like this
jonah 3y ago
Note that you're not allowed to use encryption or engage in commercial activities on the amateur bands. (In the USA but probably in other countries as well.)
- kwk1 3y ago
  An important distinction is that what's not allowed is "messages encoded for the purpose of obscuring their meaning", not encryption altogether, which means things like digital signatures can be permissible, if the public key is available through well-known means or included as a separate part of the transmission. https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4) https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4)
  - jonah 3y ago
    I almost added that footnote. Thanks for the specific reference though!

49 points by hexagonal-sun 3y ago

This is a project to connect two Linux machine's network stacks via the amateur radio bands. It uses Linux's TAP interface to read & write packets at layer 2 to/from the kernel. QPSK modulation is used at the RF layer. For now experimentation has mainly been done in a Ramsey box. The next step is to add a callsign field to the QPSK frames so the data can be legally TX'd.

drmpeg 3y ago
You'll like my IP over DVB-T2 test bed using GNU Radio. It uses the ULE protocol dvbnet driver that's built into Linux. Not shown on the diagram is that it also supports IPv6. https://www.w6rz.net/ofdm3.png https://www.w6rz.net/ofdm3.png

lobsterslive 3y ago

If anyone is looking for a really good place to get started with SDR, I'd highly recommend the RTL-SDR Blog V3: https://www.amazon.com/gp/product/B0BMKB3L47 https://www.amazon.com/gp/product/B0BMKB3L47

cogman10 3y ago
Dumb question (and maybe this isn't legal?) but are there SDR transceivers/libraries? It'd be neat to have a zigbee/zwave hub with my SDR so I could mix and match some stuff.
- cadr 3y ago
  HackRF One is an option. There are a number of others. Legality varies by country/frequency/power level. Can also make a Raspberry Pi act as a transmitter (https://github.com/F5OEO/rpitx https://github.com/F5OEO/rpitx), which could hit the zwave frequency but not the zigbee one. (Also, make sure to put a low pass filter on it.)
  - wkat4242 3y ago
    Or even better, a band pass. The output from that pin is really dirty. I wouldn't recommend it for anything that will actually transmit into an antenna. Even with filters.
- mwbajor 3y ago
  Gnuradio
- _whiteCaps_ 3y ago
  Yup, lots around. The hint is to look for 'full duplex' SDR.
- ajsnigrutin 3y ago
  Doing zigbee or zwave stuff is a lot easier with zigbee and zwave than with SDR. Just use homeassistant with something like zigbee2mqtt, and you can control your LIDL light with an Ikea light switch and xiaomi movement sensor without any issues.

kunwon1 3y ago

I recently got back into amateur radio with an SDR (listening only, my license has lapsed and I need to renew it) I found that using the FT8 protocol, I can pick up transmissions from up to ~6000 miles away, using a very cheap magnetic loop antenna mounted indoors in my apartment. My building is made of concrete slabs and I was pretty shocked that I was able to receive such distant transmissions. I think I've invested maybe $70 into radio equipment for this capability. I've listened to a lot of other signal sources, but so far FT8 is the most interesting. I can run a companion app that maps out all the contacts, it is pleasing to watch on a nice slow evening

bmitch2112 3y ago
FT8 is lots of fun. Even more fun when you go to a park or up a summit and see how far you can get out and how far you can hear. You don't need very expensive radio equipment to transmit FT8 so if you do get your licence back it is worth looking into. http://qrp-labs.com/qdx.html http://qrp-labs.com/qdx.html
- lhamil64 3y ago
  I got my license about a month ago and ordered a QDX to try FT8, but they're super back-ordered. The orders page shows that they're just now fulfilling orders from May.
  - bmitch2112 3y ago
    Do you have another radio to try it with? Another cheap option is the truSDX https://dl2man.de/ https://dl2man.de/ I have it working with my Android Phone using https://github.com/N0BOY/FT8CN https://github.com/N0BOY/FT8CN It makes for a super lightweight pack. I usually bring a 17foot whip antenna to a park or summit and get contacts all over the world.
    - lhamil64 3y ago
      No I don't, do you know if you can buy the truSDX pre-assembled, or does it just come in a kit? I'm visually impaired, so soldering is difficult for me. But I'd like to try getting on HF.

mzerod 3y ago

I have a QPSK & BPSK packet radio link to several other stations via the QO-100 satellite narrowband transponder, using a couple of Pluto SDRs and in some cases a mix/match of RTL SDR dongles and 70cm radios with transverters. Only a small group (4 so far) doing it, but we can be heard on the WEBSDR hosted at Goonhilly Earth station[1] Due to small dish sizes on RX (10GHz) we are keeping it simple and open at 1200 BPSK and QPSK 2400 with IL2P[2][3] for FEC+RS robustness, and not even close to the 2.7Khz max permitted bandwidth. [1] https://eshail.batc.org.uk/nb/ https://eshail.batc.org.uk/nb/ - 10489630 USB [2] https://tarpn.net/t/il2p/il2p.html https://tarpn.net/t/il2p/il2p.html [3] https://eindhoven.space/il2p https://eindhoven.space/il2p

sidewndr46 3y ago
This is very cool. I wish those of us in North America had access to a satellite like this

jonah 3y ago

Note that you're not allowed to use encryption or engage in commercial activities on the amateur bands. (In the USA but probably in other countries as well.)

kwk1 3y ago
An important distinction is that what's not allowed is "messages encoded for the purpose of obscuring their meaning", not encryption altogether, which means things like digital signatures can be permissible, if the public key is available through well-known means or included as a separate part of the transmission. https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4) https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4)
- jonah 3y ago
  I almost added that footnote. Thanks for the specific reference though!