Thanks for the reference. I was almost certain it was 80 m. But I see that it can be adapted to nearby bands. I also had figured it was a
shunt hartley using copper tubing for L1. That tubing is hot and dangerous to touch, I believe. Normally, L4 goes straight to the plate and C2 would isolate L1 from that voltage. A ground clip near the center of L1 is then used. Safer. R2 is a grid leak, so it's self-biased and grid will be negative with respect to the cathode. Filament is 6 Ohms so R1 sum should be 10 times that, I think. (Rule of 10.) Type 10 says "power audio". Just notes for now.