My meshcore repeater build

[KBSherwood]

Good Afternoon Everyone, 

Recent events in the world have spurred me to revisit some of my off-grid comms plans, and while voice is well taken care of with all my GMRS kit, data and text were still relying on centralized providers that would likely be unavailable or congested to the point of being unusable in any real emergency, can be surveilled, have records subpoenaed, etc. Previously, I have toyed around with Reticulum network stack (hardware agnostic, very very cool project) using some cheap LoRa 900mHz ISM radios, and while awesome, it's not very user friendly for the less tech savvy, requires network build out and access to the infrastructure and overall wasn't a great option for my goal. So I repurposed those nodes for Meshtastic. Seemed great, had lots of users around, and my "pokedex" of contacts was filling up fast, however some architectural decisions by the creators have made Meshtastic almost unusable where I am. In Meshtastic everything is a "repeater" and those repeaters love to spam useless telemetry about each node, that along with the fact they limit network transversal to 7 hops (if you are in a saturated area 7 hops could be within a few blocks) I had a less than 10% success rate getting messages out. Its advertised as an emergency comms solution, but in reality its best effort text messaging that I wouldn't trust for crap. 

Enter MeshCore, its another project that aims to correct the shortcomings of Meshtastic: only designated repeaters actually forward packets, network traversal is set to 64 hops, and  telemetry is not broadcast, along with some other differences. The project is still very young, but I was immediately impressed with the amount of nodes here in the Pacific Northwest, we can reliably communicate between British Columbia, CA all the way down to Medford, OR. I flashed one of my lora radios with their built in web flashing utility (make sure to enter boot or DFU mode) and connected to it with my phone via bluetooth (important: the basic lora radios are "companion's" meaning they are connected to your phone, and you text through an app that relays to the lora device which then transmits) and threw it up on my roof. I knew that with the slow rate of repeater advertisements that I would need to wait a few days to hear the "adverts" from the various repeaters in my area before the system could build routes to send out data to the wider network. Well after about a week of that, I had received a whooping 3 packets. Cool... cool. A little disheartened I reached out to some of the local Meshcore users to see if what I was experiencing was the norm, faulty hardware, bad settings, etc. Everything seemed good, and it was simply an issue of using sub-watt radios without great line of sight. Determined to throw good money after bad, I decided to at least give building my own repeater a shot, if that worked, great. If not, these $30-50 radios would go back in the bin and I wouldn't be that much worse off. 

Originally I was going for a roof mounted node, however after seeing other Meshcore folks build "tree-peaters" I decided that would be the best proof of concept and would avoid me falling off the roof. I ordered everything below off of amazon and started building. My repeater consists of the following bits:

1. Heltec T114 915 mHz lora radio 
2. A 5600mAh 3.7v li-ion battery
3. A "muzi works" 915mHz 17cm lora whip antenna
4. A "soshine" 5v 6watt mini solar panel
5. A "peakmesh" li-ion battery protection circuit - the T114 comes with a built in solar charging circuit, and a built in battery management system, however its shutoff voltage is 2.5v and the batteries can be permanently damaged by over discharging them, this board shuts them off at 2.9v a much safer level. 
6. A generic black project box

Total cost was about $100, I could have knocked this down to $80 or so by not purchasing a GPS module for the T114, I ended up not using it anyway. Built it in an hour or two over a weekend and used an arborists line to throw it up in a tree, about 40ft up facing south east. It has been working phenomenal! I am connected to two different repeaters, bridging a gap between a few suburbs and connecting the wider area to the meshcore backbone. Even in the 20* winter weather, I've never seen the battery drop below 88% and the oversized solar panel quickly charges the battery back to full power. I am forwarding thousands of data packets daily along our little data path and for $100 and some time I have made Meshcore messaging accessible to a few immediate neighborhoods, and have increased the coverage and reliability of the local network as a whole.  

Its a very fun little project for anyone who is interested in tinkering and playing with radios. Let me know if you have any questions and I'll do my best to answer them.