Strength, Safety and Style

Antennas are a very important part of a radio station, from big beams on high towers to simple masts on urban houses. They are exposed to the changing weather conditions, mechanical strain, UV radiation, humidity etc. The antenna mast or tower design and installation present a challenging task due to a number of factors that have to be taken into account. Durability and safety are of prime concern so as to ensure the antenna remains fully operational for a long time. The right guying is therefore extremely important. Steel guying wires are still very common, however they are heavy, difficult to work with and their strength deteriorates with time due to corrosion and general ageing. Their electrical conductivity is an undesirable feature as this interacts with the antennas and deteriorates their radiation pattern. Thanks to the recent developments of materials, both amateur and professional users are changing over to non-conductive guys and ropes and will never go back to using the steel wires once the benefits are fully appreciated. The non-conductive synthetic fibres have all the necessary qualities: high strength, negligible elongation but with good flexibility, long life, low wet-ability, minimum bending radius giving the ability to tie knots, good UV radiation resistance, weather durability and resistance to acids and alkali. Mastrant optimized lines are made from proven modern materials such as Polyester (Mastrant-P) and Dyneema (Mastrant-D and D-F2). The range covers products for a variety of applications, from thin support lines used for tying wire antennas and beams, to guys for supporting small and portable masts and vertical antennas, to anchoring ropes for high antenna towers tens of metres high. The product line is supplemented by a wide range of stainless steel accessories. The development, testing and quality control of all these products ensures a superior product delivering long life. They are subject to continuous tests in laboratories as well as in real conditions of use, in co-operation with a number of professional users.

"Is Mastrant made from Kevlar?"

People are used to using Kevlar for "strong ropes with small elongation" - no matter what material the rope is made of. Kevlar (or Technora, Twaron, etc.) is a brand name for ropes from aramid fibres used in the past. Nowadays, the material has been replaced by LCP (trade name is Vectran) which has better properties. However, there is a better material for ropes for anchoring - high tenacity polyethylene; trade names are Dyneema or Spectra. It has excellent UV resistance, higher knot strength and much lower specific gravity in comparison with Vectran. This is Mastrant-D - double braided rope, core is braided 100% Dyneema SK 75, inner cover is Polyester staple (only on ropes with diameters from 6 mm and up) and outer cover is Polyester 12, 16, 24 or 40 (depending on the diameter). We used to offer ropes from Vectran in our assortment (it is Mastrant-V). Recently, we replaced it with the new rope Mastrant-P which is better for our purpose (guy-wire). This is braided rope with twisted cores (core: Polyester, parallel-arranged twisted cores, cover: Polyester 12 or 16). It has lower strength and higher elongation than Mastrant-D, but all other properties needed for guying are similar. Moreover, it has much higher knot strength and Mastrant-P is dramatically cheaper. Thus Mastrant is not from Kevlar. Mastrant is optimized for anchoring.

Design your own antenna support system

Precise design of the antenna support systems and their safety presents a difficult task for which no ready-made solution exists. Radio amateurs often simply use common sense and experience, sometimes relying on incomplete knowledge of the materials used. There has been no simple solution until now. Based on the development of the special Mastrant lines, a methodology has been designed for determining the necessary material specifications and calculating stress values for various parts of the antenna support systems and anchoring elements. Simply use our on-line calculator, which after entering the basic data, calculates the required values and provides recommendations on the choice of materials to use. This ensures that the antenna support system is designed to be safe and reliable under all conditions for many years to come. For details go to Calculations.

Comparison with steel ropes