With inputs from many, I have settled on making the mountain-top 65' towers out of heavy duty Rohn 45G SR (solid rod) with 2 guys per tower, using three 20' sections (and a 10' base section having 5'
How about having an adapter machined to get from the 5" tube to the 2.5" rotator mount? It might be kinda heavy but should meet the strength requirements. 73 Roger (K8RI) ____________________________
how about a toothed belt drive between rotator and mast. I'm assuming that the 5" OD pipe is very thin wall (either that, it's literally going to weigh a ton). But this is getting pretty non-standard
I should have added "if the rotator is capable" Friend of mine that used to live in Ithaca MI, John WD8RXP, had a self supporting system that was IIRC 180 or 190'. The base was 100-120' with the top
I would go for 5" masts or larger on that location for sure. A typical ham rotator on that installation will not last very long. Go for a commercial gearbox and drive like a large garage door opening
I doubt there's much difference in strength between the 2dia x 1/4 wall and the 2.5dia x 1/8 wall mast, however you can calculate this yourself using any mast software. K7LXC sells a product for this
There is only about a 2% difference between the two sizes of mast you listed, with the 2" x 0.25" being the stronger. Assuming 87,000 psi yield strength, they would handle a max of about 3900 ft-lbs