DX Engineering vertical antenna fixed base assemblies are intended to support your own 2 in. o.d. HF lower antenna base section in a fixed vertical position. They consist of a unique, reinforced fiberglass insulating channel, which has twice the strength of commonly used nylon and other insulating materials. It is fastened with stainless steel V-bolt saddle clamps to a rugged 1/4 in. aluminum mounting plate. The aluminum mounting plate may be bolted to a secure, flat mounting surface or to the recommended galvanized steel mounting pipe (up to 1 3/4 in. o.d.).