After 4 (long) years, I can finally make good on my promises to revisit building a DIY Layer 1 and Layer 2 with my SDRs. I've been calling it #pigeon (using my RF library #sparky to build it -- my #hztools successor) -- I've written down as much as I could and have just hit "publish" on a now 4-year old draft post (now 16 posts) at https://k3xec.com/pigeon/