7.5mm insulated mast guying cable
7.5mm insulated cable for guying of masts. Sold by the metre (discount). Excellent performance under climatic conditions (water, sun, ice), high breaking strain, very good RF insulation, lifespan of more than 40 years!
Our cable is sold by the metre!
Not only to avoid wastage by ordering more cable than you really need, but also so that it can be sent in one single length which allows you to cut your guys without worrying about coming to the end of the reel.
Our tariff reduces progressively depending on the length ordered (minimum 25 m):
• From 25m to 100m : €1.15/metre
• From 100 to 400m : €1.10/metre
• Lengths over 400m : €1.05/metre
Wire mast guys, because of their unforeseeable resonant effects, can influence considerably the radiation pattern of antennas. When directional antennas are installed at the top of the mast such guys can necessarily induce stray current which result in an absorption effect and a degradation of the radiation lobes.
The current induced in the guy system can reach a maximum of twice the wavelength. If it is desired to limit this it would be necessary to insert insulators into the guys at least every half wavelength for the frequency worked. If,for example,the mast carries antennas for 28MHz it would be necessary to insert insulators at least every 5 metres. (See Resonance of Guys by F5AD - french language)
DX Avenue's recommended solution (and used,amongst others,by F2DX for decades) consists of the use of non-metallic guys, without reducing in any way the mechanical strength of the installation.
Deltex cable which we have chosen is characterised by very slight stretching under tension, complete elastic memory, excellent performance in all climatic conditions (water,sun,ice), high breaking strain, very good RF insulation, light weight and a lifespan of more than 40 years!
Made in France from first choice high viscosity materials (polyester), it is the first non-metallic cable made in the world from monofilament. It is the result of 30 years of professional experience acquired in the field of thermoplastics and from 10 years of specific research.
As a result of stringent tests, Deltex® estimate that the mechanical lifespan of their cables subjected to 60% of their breaking strain will be greater than 70 years! For comparison, cordage made from aramide fibres (Kevlar®, Twaron® etc), under the same continuous tension, break after only 6 months (they are also very much dearer). That is why the working load recommended for such type of cordage is 30% of their breaking strain. In addition their manufacturers almost never give any indications in respect of their lifespan.
F8FKI used 450m of this insulated cable to guy a 54m (177 ft) high vertical antenna for the 160m band (1.8 MHz)! Watch the video
• Cable diameter: 7.5mm
• Colour: black
• Breaking strain: 2000 daN (kgF)
• Volumetric resistivity: > 1 x 10 to the power of 13 Ohms/metre
• Surface resistance: > 1 x 10 to the power of 15 Ohms/metre
• Dielectric rigidity: 60 kV/mm
• Composition: 7 plaited strands of top quality monofilament
• Lifespan: greater than 40 years between -40°C et +70°C
• Weight: 2,5kg/50m
Usage and advice from DX Avenue
• The endings of the guys can be made by traditional stirrup type cable clamps ("U"). Consider using three 8mm cable clamps and a thimble terminal for each attachment point. The use of cable clamps reduces the breaking strain of the cable by 15 to 20%. The distance between the cable clamps must be equal to 6 to 8 times the cable diameter (i.e. about 5.5cm).
• A tension adjuster (M12 or M14) will also be necessary at each anchorage point when using cable clamps.
|With regard to freestanding masts !
Because a freestanding mast isn't indestructible, especially when carrying directional antennas, it can be prudent to add a layer of safety guys on the highest point.
A telescopic mast is equally affected and its happy owner would not ask further questions if he is surprised by a sudden violent wind before he has had the time to lower it.
The safety layer (normally consisting of 3 guys) has already proved its worth with many radio amateurs but some of them have added them too late resulting in twisting or falling of the mast. Be prudent and foresighted, especially if you have neighbours!
Do not hesitate to contact us if you have any doubts or questions.We can look at your project together. Long lengths (>500m) are possible.