After years of using a very heavy Hop Hornbeam nest pole which was always quite scary and Herculean to lift and lower (both for humans and chicks), we just made 4 new boxes and came up with a new design that seems quite ideal.
We used two lengths of galvanized chain link pole of different diameters as available at Home Depot and other places for each box pole set. We were aiming for a 12 foot box height since we had had success with that height before. Adjust pole length purchases if you are looking for a shorter or taller ultimate height.
We used a 10 foot base pole 1 7/8" diameter and an 8 foot upper pole of 1 5/8" diameter. We buried approximately three feet,in the ground and tamped it well while backfilling.Time will tell if this is deep enough for long term stability in all types of soil or not.
The upper pole is small enough in diameter to just telescope inside the lower. We drilled a hole through both poles and used a small diameter 1/4" hitch pin to secure.them, when extended ,with an overlap of about 24 inches .We also drilled holes at top of upper pole to attach box to. In addition we put an easily purchased cap on the end of the top pole.
Luckily I already had 10 foot lengths of the lower pipe on hand ,otherwise set-up is a bit pricey , but should last forever ( for all practical purposes). You just need a small stepladder or even a bucket to stand on to inspect/clean/band nests after telescoping down.one box had a handy rock near it to stand on. Be careful of your fingers as you lower or raise poles. An assistant is ideal.
After installing pole and box, it is simple to,use a large pipe wrench to fine tune box orientation by twisting lower pole I have set one box so I can get a perfect view in the distance of the box entrance as I have my afternoon tea.
Looking forward to many safe and easy nest inspections in the years ahead!
Feel free to contact me if you want further details..