Any ideas for installing a new antenna mast into an old antenna hole?
OLD: I have an old 3.5 inch ID steel tube sunk in 30 inches of concrete. I'm guessing this was an old satellite dish cut off flush with the surface (unfortunately). No threads but the steel is 1/4 thick (or so) and in good shape and it goes down to 30 inches in the concrete.
NEW: I simply need an antenna mast of about 12 feet high for a new WISP 802.11 antenna & radio setup. Winds can be high at times. Soil is rocky clay. I prefer NOT to have guy wires as the kids play in that area.
IDEA: The best idea is to find a way to shove a 3.5 inch OD pipe 30 inches into the existing pipe and then thread successively smaller pipe down to 2 inches for the final mast. But I can't find a source for 3.5 inch OD pipe that has threads on at least one end so that I can put a reducer on that end.
COMPROMISE: I can easily find 2 inch and 1 1/2 inch threaded galvanized water pipe with reducer fittings and caps - but I can't find 3.5 inch water pipe and associated fittings for the bottom portion of the mast.
TWO QUESTIONS: Q1: If I stick with the original idea, where would I get a 3.5 inch OD pipe that has threads that can hold a reducer to more available widths?
Q2: If I go with what I have right now, how would YOU shore up the pipe but still allow easy removal for maintenance?
DETAILS: Currently it's working but physically wobbling. I remove the entire mast to service the antenna.
The mast is comprised of a five foot length of 2 inch ID threaded galvanized water pipe sitting 30 inches deep inside the existing 3.5 inch ID iron pipe cut flush at the concrete. This five foot length of water pipe sticks roughly 2 1/2 feet out of the ground where I then threaded on a reducer which couples easily to the 10 foot length of 1 1/2 inch ID threaded water pipe forming the bulk of the mast, and which is capped at the top (to prevent water from filling the pipe).
The 14 dBi planar 2.4 Ghz antenna at top is roughly pointed at the WISP access point; the Bullet M2 radio tells me it has an ACK/Distance of
55/2.6 miles respectively (I'm not sure if that's important); this radio sees a signal strength of -56 dBm (pretty good); with a transmit CCQ of 83% (just ok).It's working - but it's not a permanent solution.
I am stuck at HOW to fix the antenna in the ground so that it won't wobble & spin (short of digging a new hole & concreting it in) yet being able to service the antenna (I have ladders but not a 12 foot high step ladder - plus the ground is sloping so it's unsafe to ladder it).
Do you have ideas how to affix the antenna mast into the old 3.5 inch ID hole while still being able to remove the entire mast for antenna service?
NOTE: In the future I'd like to add a TV antenna but that's not the primary goal.
All ideas welcome.