I’ve noticed that the KISS implementation on a lot of these devices is a forked over version of the Rnode. He used the Sx 1276 chip as well because it has really good RX sensitivity at the lower rates. He also has a newer and easier form of KiSSattach. https://github.com/markqvist/tncattach
I like your thoughts about changing modulation on the fly. I’ve seen it done with higher level stuff , Ubiquiti and others. Just wonder how much it would slow things down. Cause I think you would do that per packet. Maybe per connection. Right now I’m just interested in tying a few of the different versions and seeing what works. No real goals in mind, just checking it out and experimenting. I’ve thought about a repeater, but that would kill the great RX sensitivity , but a digi would be good. A old style repeater separated by distance and a link would work. Might even try Winlink on it and see what what happens when I stir that pot! So many ideas. Steve N0FPF On Sat, Jul 31, 2021 at 12:58 PM Kristoff <[email protected]> wrote: > Steve, > > > I also have this model: > > https://www.amazon.nl/DollaTek-LoRa32-SD-kaart-draadloze-module/dp/B07RXSKPBX/ > > The disadvantage is that it lacks the 8 Mbit PSRAM chip (which is on the > T-beam) so the ESP32 is a bit short on memory for embedded python. (less > then 1 MByte of RAM available). > > > Software development-wize, perhaps it makes more sense to turn the > radio-device into just a dumb 'packet-modem', connect it to a > single-board computer (say, a raspberry pi) and do all development > overthere. That way you can run higher-level code, easily interface with > the internet, connect other devices (e.g. a VHF/UHF packet mode), etc. > > Last week, I found this python module for processing aprs message (*) > which I think would be a good basis to do some experimental development > for aprs-code. > > > > > I do like the sx1276 chip. It has a couple of nice features. > > - as it also has a FSK modem, It might also be able to transmit POCSAG > (paging) messages. If this works, we should be able to build a > APRS-to-POCSAG gateway with just one piece of hardware: send a aprs > text-message to a certain APRS node and it transmit that message as a > POCSAG paging message. > > I once wrote some code to create pocsag-message. (**) > > > - The automatic header-detection in lora is nice, > This means that if you send a packet with (say) a coding-rate of 4/8 to > a lora-node configured with 4/5, the chip will still receive and decode it. > > So, if you know that you are in area with bad APRS-over-lora coverage, > you can switch to a coding-rate that provides better error-correction > (like 4/8). Your packets will become larger (by 37.5 % in this case) but > your packet might still arrive, which it might not have done with a > coding-rate of 4/5. > > Note that that bandwidth and Spread-Factor do need to match. If not, > your packet will not be demodulated/decoded. > > - Another nice thing is that, although the chip does have CRC-generation > and CRC validation in silicon, it will still pass packets to the > receiver, even if they fail the CRC check. > It will flag it as 'CRC error', but the code on application-level will > still be able to retrieve it. > Most other radio-chips I have looked at so far do have do not do this > and will silently drop that message. > > This would allow for a nice lora "DX-ing" mode by implementing > additional error-correction code on application-level. > > > > > Ah yes, there is also a GNU Radio implementation of the Lora PHY. (***) > I haven't tried it yet, so I do not know if it works but It would be > interesting to experiment with this, e.g. tweaking the parameters even > further to do even further DX. > > > > I am not on Facebook. > > I prefer mailing-lists for in-depth discussions. To get real-time help, > ... I am on matrix / element.io which is an open-source and > decentralized IM/voice/video service. > There are quite some open-source groups reachable via matrix, either > directly on matrix itself or via bridges to IRC or some other IM protocol. > > It's used the GNU Radio community. > > > (*) https://github.com/ampledata/aprs > (**) https://github.com/on1arf/pocsag > (***) https://www.epfl.ch/labs/tcl/resources-and-sw/lora-phy/ > > > 73 > kristoff - on1arf > > > On 31.07.21 20:31, Steve wrote: > > I gave two of the TTGO units including a couple of Rnodes. > > > > I’m going to try a couple of the existing firmware options out there. > Some > > are KISS based some are not. I like the possibility of using the wifi or > > Bluetooth with the TTGO with some of the APRS programs fir the phones. > > > > Seems for a mobile device, not have a extra board such as a PI might be > > nice… we’ll see! > > > > The TTGO can also be used for this: > > https://tinygs.com > > > > The Rnode guy is also implementing a MESH system but is only in the alpha > > stage. Beyond my ability. > > > > I’ll have to get back to you on Freq, I only got my TTGO going last night > > and didn’t bother to look! > > > > There is a LORA APRS group on Facebook, grin, that is mostly from Europe > > who have a lot of experience with this . > > > > Steve N0FPF > > > > > > > > On Sat, Jul 31, 2021 at 11:20 AM Kristoff <[email protected]> wrote: > > > >> Steve, > >> > >> > >> Your project interests me too. > >> > >> We are using this hardware: > >> https://github.com/LilyGO/TTGO-T-Beam > >> > >> We are on 433.775 MHz, 150 KHz, SF12, 4/5 > >> What frequency and what mode do you use? > >> > >> > >> The software comes from this project: > >> https://github.com/lora-aprs > >> But if the code of your project is standard arduino, it shouldn't be to > >> difficult to port it to ESP32. > >> > >> Apparently, there are also some high-altitude balloon projects that use > >> lora for their telemetry download. > >> > >> > >> > >> My personal interest is to use this for doing some software > >> experimentation, so I use micropython on the ESP32 (fast development) > >> and not the arduino code. > >> > >> > >> > >> 73 > >> Kristoff - on1arf > >> > >> > >> > >> > >> On 31.07.21 20:05, Steve wrote: > >>> I connected it to my 10 db Omni antenna at home right at the base to > >>> minimize the loss. > >>> > >>> I was impressed that it was heard around some of the hills in west > >> seattle . > >>> I have plans to put a IGate at a high point around the end of the > summer. > >>> > >>> I also found a small bi- directional amp too. Boost it to a watt or > two. > >>> Just don’t want to kill the receive sensitivity. Around $60. > >>> > >>> It’s all in the antenna. > >>> > >>> Steve N0FPF > >>> > >>> > >>> On Sat, Jul 31, 2021 at 10:59 AM Tom Russo <[email protected]> wrote: > >>> > >>>> On Sat, Jul 31, 2021 at 10:35:44AM -0700, we recorded a > bogon-computron > >>>> collision of the <[email protected]> flavor, containing: > >>>>> I have interfaced the Rnode Lora device. It does Kiss and used a PI > 3. > >>>>> Pretty straight forward. > >>>>> > >>>>> https://unsigned.io/projects/rnode/ > >>>>> > >>>>> I was able to do a client and a IGAte. > >>>> That is pretty cool! > >>>> > >>>> -- > >>>> Tom Russo KM5VY > >>>> Tijeras, NM > >>>> > >>>> echo "prpv_a'rfg_cnf_har_cvcr" | sed -e 's/_/ /g' | tr [a-m][n-z] > >>>> [n-z][a-m] > >>>> > >>>> _______________________________________________ > >>>> Xastir-dev mailing list > >>>> [email protected] > >>>> http://xastir.org/mailman/listinfo/xastir-dev > >>>> > >> _______________________________________________ > >> Xastir-dev mailing list > >> [email protected] > >> http://xastir.org/mailman/listinfo/xastir-dev > >> > _______________________________________________ > Xastir-dev mailing list > [email protected] > http://xastir.org/mailman/listinfo/xastir-dev > -- Pardon the brevity, sent from a mobile device. So there. _______________________________________________ Xastir-dev mailing list [email protected] http://xastir.org/mailman/listinfo/xastir-dev
