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LoRa APRS & DW
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I found an interesting side project to interface with DW.? LoRa APRS using a TTGO T-Beam.? The project is here:
I have a couple 70cm T-Beams.? I flashed the firmware and configured the devices.? So far the T-Beam interfaces with DW 1.7B? and the RPi 4 just fine with the "SERIALKISS /dev/ttyUSB0 115200" configuration. I'm still tinkering with the setup.? Trying to figure out if/how to "route" traffic to/from the SERIALKISS device like we can between CHANNELS. Good luck, N1OBU |
开云体育I don't think this is going to work as these two solutions are "competitors" if you will and they are effectively doing the same thing.? This T-beam device is acting as a KISS TNC interfacing to the RF world using LORA and it's own radio.?? When using Direwolf with the SERIALKISS command, it will act as a KISS TNC to the RF world using a sound card creating say 1200bps AFSK, 9600 FSK, etc. into your externally provided radio. What you can do is have both running and configured to communicate to the Linux AX25 stack.? At that point, you can run a program like APRX to do APRS things on each of the TNC+Radio setups. --David KI6ZHD On 12/04/2021 05:14 AM, Douglas Pervine
wrote:
I found an interesting side project to interface with DW.? LoRa APRS using a TTGO T-Beam.? The project is here: |
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And, there's another point: Lora, last I heard, is a proprietary format
and needs a patent license. So at least in the US, there is no possibility of a Free Software SDR implementation, even if one had an adequately wide-band SDR. In this respect it is similar to AMBE (or maybe that's expired and it's similar to AMBE2). Separately from that, I'm also curious if the Lora protocols fall under the Part 97 Spread Spectrum rules and how that works. I have lost track of the rules and never tried to operate spread spectrum. (I am guessing people are talking about operating Lora hardware under amateur rules, rather than talking about gatewaying Part 15 data to and from Part 97 systems, which seems also unclear to me.) 73 de n1dam |
开云体育The LILYGO TTGO T-beam devices don't use Part 97 frequencies.. they use Part 15 that don't have the same requirements: ?? --David KI6ZHD On 12/04/2021 05:17 PM, Greg Troxel
wrote:
And, there's another point: Lora, last I heard, is a proprietary format and needs a patent license. So at least in the US, there is no possibility of a Free Software SDR implementation, even if one had an adequately wide-band SDR. In this respect it is similar to AMBE (or maybe that's expired and it's similar to AMBE2). Separately from that, I'm also curious if the Lora protocols fall under the Part 97 Spread Spectrum rules and how that works. I have lost track of the rules and never tried to operate spread spectrum. (I am guessing people are talking about operating Lora hardware under amateur rules, rather than talking about gatewaying Part 15 data to and from Part 97 systems, which seems also unclear to me.) 73 de n1dam |
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"David Ranch" <direwolf-groupsio@...> writes:
The LILYGO TTGO T-beam devices don't use Part 97 frequencies.. theyI see: 433 MHz 868 MHz 915 MHz 923 MHz My understanding is that 868 is for Europe only. 433 and 915, and maybe 923, are allowable under Part 15, but I am not sure the Lora modulation/power is ok at 433 under Part 15 (which is low duty cycle only?), and my impression is that the Lora norm in the US is to use 915 under Part 15. But, one can operate a 915 radio under 97 or 15, if the emission type meets both rules. This seems similar to people using wifi hardware at 2.4, 3 and 5 GHz in spectrum that is authorized for both Part 97 and Part 15 use, but choosing to operate under Part 97 rules, sometimes with amps and higher gain antennas. I would think that an APRS network would have to treat a Part 15 radio as "internet" rather than "amatuer radio" in terms of gatewaying, and that's what I was trying to ask about/understand. 73 de n1dam |
开云体育Yes, part 97 can use Part 15 Radio Frequency devices. Witness Bluetooth on transceivers. ?LoRA is documented. APRS over LoRA is completely fine.On Dec 4, 2021, at 17:34, David Ranch <direwolf-groupsio@...> wrote:
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开云体育I
see:
Correct.. these are unlicensed ISM frequencies and there are many others as well: ? but I am not sure the Lora modulation/power is ok at 433 under Part 15 (which is low duty cycle only?), and my impression is that the Lora norm in the US is to use 915 under Part 15. Anything is generally allowed on ISM frequencies within specific power parameters, etc. But, one can operate a 915 radio under 97 or 15, if the emission type meets both rules. This seems similar to people using wifi hardware at 2.4, 3 and 5 GHz in spectrum that is authorized for both Part 97 and Part 15 use, but choosing to operate under Part 97 rules, sometimes with amps and higher gain antennas. Correct.. up to certain power levels but also without being allowed to run encryption, etc. I would think that an APRS network would have to treat a Part 15 radio as "internet" rather than "amatuer radio" in terms of gatewaying, and that's what I was trying to ask about/understand. APRS is just a protocol that you run on top of some other transport be it LORA, 1200bps AFSK, etc.? Your choice of power levels and other features will determine which frequencies are appropriate.? For those of us in the US, then comes the rules be it Part 97, Part 15, etc.? Gatewaying into the Internet is essentially moot as the FCC has no jurisdiction / rules / etc there. --David KI6ZHD |
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Hi Douglas,
I'm in the same position as you. I came across that project over the holidays and am also looking for a way to route packets from the serial kiss interface in the T-Beam to a 2m radio.on Channel0. The setup would be something like direwolf running on an RPi with one of the LoRa boards connected via Serial TNC and a 2m mobile radio connected via CM108 with PPT. My aim would be to set it up a portable "fill in" digipeater that will take the APRS data from the LoRa boards and then digipeat them via the higher powered 2m radio. I'm fairly new to this and have only recently set up a 2m digipeater for testing and still learning new things. Have you had any success in finding a solution for this? 73 Tom EI5IEB |
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Tom,
Not yet. It seems the 'serialkiss' parameter is only for KISS terminals. It doesn't work with a KISS TNC so well. Packets kept bouncing back-n-forth (couple redundant loops). Terminal to terminal the LoRa devices work great. For now I've put the LoRa devices on the back burner in hopes DW will accept them as a TNC and assign a Channel number to it. Good luck |
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Direwolf is not the platform to attach to an external TNC.? Direwolf is a TNC plus some applications. On Wed, Jan 12, 2022 at 4:31 PM Douglas Pervine <douglas.pervine@...> wrote: Tom, --
John D. Hays Kingston, WA K7VE / WRJT-215 ? |
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Thanks for the update Douglas,
Good hear the devices work back to back pretty well. It would be great if we could find a way to have a system working as a fill-in digipeater and route data from the LoRa boards to a 2m rig. I'll continue to play around with these and see what I can come up with. I might have to use some other applications, if I get this working I'll update this thread. Thanks for the replay John,? Would you have any suggestions as that what platform may work for us? 73 Tom EI6IEB |
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Hi Tom and the others on this thread:
I have several LoRA-enabled 900 MHz USB-connected radios that are flashed to be stand-alone KISS serial TNCs. Two are unsigned.io RNodes and the other two are TTGO LoRA V2.1 radios. They're all flashed with the unsigned.io rnodeconf tool. In linux-land, the RNodes present as /dev/ttyUSB0 and the TTGO units as /dev/ttyACM0. (I don't know why they behave differently, except maybe cause of the USB chips they use.) When connected to a Windows box the RNodes run without any USB serial driver, while the TTGO nodes require a serial port driver available on git-hub?). I have a node set up at my house, on an antenna in the window, and it connects just fine via USB to APRSIS32 running on a Windows 7 box. It presents as a KISS serial modem. I have the LoRA radio set up for approximately 1100 baud to maximize the range. Like you and others have discussed, it'd be great to plug at least one of these into a RPi running direwolf, and get "cross-band" connectivity. Couldn't I set up direwolf to recognize a kiss connection from a serial port within the same RPi, and pass packets between the LoRA radio and the radio natively connected to direwolf? I'm mildly interested in this since my tests at +17 dBm tx out (the max that the Semtech SX1276 does) has done over 10 km in typical suburban terrain. (Note that my house is about 200' higher than my part of town, so maybe that's cheating...) The other end is another of those radios, connected to a Windows PC in my truck via USB, with the win pc running APRSIS32 as well.? Anyway, I would like to be able to use these LoRA radios as an adjunct, or backhaul, or just another band radio that gets packets from 2m and spits them out on 900, and vice-versa. Cheers and 73 - Jon N7UV |
开云体育Hello Jon,I have a node set up at my house, on an antenna in the window, and it connects just fine via USB to APRSIS32 running on a Windows 7 box. It presents as a KISS serial modem. I have the LoRA radio set up for approximately 1100 baud to maximize the range. Like you and others have discussed, it'd be great to plug at least one of these into a RPi running direwolf, and get "cross-band" connectivity. Couldn't I set up direwolf to recognize a kiss connection from a serial port within the same RPi, and pass packets between the LoRA radio and the radio natively connected to direwolf? This won't work as Direwolf an KISS TNCs effectively create duplicate functionality.? There is no way to decouple the APRS stack from the KISS-TNC functionality in Direwolf.? Instead, consider using some alternative APRS applications under Windows that support a KISS TNC such as: ?? - APRSIS32 ?? - YACC ?? - etc --David KI6ZHD |
开云体育On 5/3/2022 8:15 PM, Jon Adams wrote:
I do not believe you can use Direwolf as an APRS client for a standalone KISS TNC. I have experimented with LoRa myself, at one point I actually ran APRS in the field. My client radio was a SparkX Pro RF 1W board running homegrown KISS firmware on the SAMD21 MCU. Pretty sure I was running APRX in a odroid C1 for the APRS part. At home - only about 80' above sea level but looking across flat marshland to one direction - I had a Larsen 5dBi groundplane hanging in an upstairs window with a Feather 32U4 LoRa hanging on the antenna pigtail, also running custom KISS firmware to, IIRC, APRS-IS but I can't remember for sure. Antenna on the car was a little mag mount of dubious gain. Nonetheless I tracked out across marshland a good 7-8 miles. Later tests, not using APRS, with the same radios saw reliable coverage 40km across flat land to a bridge about 200' above sea level. These tests were generally done with BW 125kHz and SF 7 or 8 IIRC. I'll have to dig up the experimental code at some point. I did specifically avoid the LoRaWAN channels here in US915; we do have pervasive SmartMeters, a mesh network on 915MHz running 1W with short data packets (despite being short, the density of meters in neighborhood means you frequently see pings on the waterfall). Since then I've had multiple LoRaWAN gateways installed on hilltop sites for actual LoRaWAN operation, and, with good LoS paths, see 15km+ paths to fixed barefoot (+20dBm max) devices (motes) in the field, using 2-5dBi antennas. LoRaWAN's Adaptive Data Rate generally reduces transmit power in the field motes to +10dBm. You might be interested in Dan Fay KG5VBY research with higher-power LoRa: 73, Dana? K6JQ |
John Hays - K7VE / WRJT-215
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