Basically, it is about the wall thickness of the Al pipe. This also determines its strength. For 7 el. YAGY, an AlMg pipe of 28 mm is more than enough. Never anchor the pipe at the top of the antenna. The best, or ideally, is at a height of 2/3 from the ground. To connect individual parts, it is necessary to have spacers turned and drilled between the joints of the mast. In an emergency, hard wood can also be used. A lathe is not necessary. There is indeed a problem with disassembling the mast (in wet conditions), but a saw can always be found. Very good and rarely used are armored pipes. They are light and strong. They can be obtained throughsome electrician. In an emergency, it is also possible to use painting extensions, they sell paints and varnishes. It needs to be tested. Its length is approximately 2.5 m. It is necessary to secure the base of the mast against shifting and drilling into the ground. In an emergency, a can from pâté is enough. For anchoring, use regular laundry cords.