[UK-CONTEST] Non-conductive guy ropes - follow up

[Kerr, Prof. K.M.]

A few weeks ago I asked on the reflector for advice regarding non-conductive ropes for guying towers. I received a great deal of comment in reply and to everyone who mailed me off reflector a big thank you. I promised to summarise what I found out, what happened etc and a few even mailed me to encourage me to do so. I know many of you will have solved these problems already but......
The job was to upgrade the two sets of three blue polyprop guys on my P80 to something a bit more substantial since (a) WOJ had been bending my ear for years, rightly so, about the inadequate installation I had and (b) the new rotator (OR2800) was much heavier than the old T2X and the planned new antenna would have a 41ft boom and 7 elements.

Non-conductive ropes
One word sums this up - expensive! Nevada do not stock guy-rope grade Phyllistran any more. Of the other synthetic ropes out there, dyneema seems to be the buzz word these days. Parafil is available in the UK but is very expensive and special splicing ends for providing an anchor for shackles etc are very very so. Several reflectees mentioned Mastrant (mastrant.com) as a source of various ropes and fittings. These guys in OK-land (including OK3FLY and a well known contester, Martin, OL5Y) supply several ropes including pure dyneema rope and some with a dyneema core and a polyester webbing outer protective coat (Mastrant D-series). This stuff was more cost effective that importing Phyllistran from Array Solutions and compared to the myriad other sources of dyneema rope on the web, and even in Radcom, easily won out on cost. Their web-site gives comparative data showing claimed comparison with steel rope. I had steel rope ready for two lower sets of guys but wanted the top set to be non-conductive. I chose Mastrant D10 (10mm dia) which has, I think, an 8mm dyneema core and an outer polyester web, making its strength similar to approx 6-7mm steel.
A UK source for this is Vortex Antennas (vortexantennas.co.uk), though you can deal direct with the Mastrant guys. I went to Vortex and, to cut a long story short, a supply problem with D10, led to Steve at Vortex securing me 100m of D12 (10mm dyneema core) for the same price as D10, courtesy of a kind offer from the Mastrant guys. Quite a good deal for me, though the fittings then cost more but still a great offer!
Wire grips as used to secure/splice steel rope are not recommended for Mastrant rope, instead they recommend a fist grip which Mastrant can supply. These have a greater length/surface area for contact with the rope, the contact area has a spiral ridge for better bite, yet after full torque grip, they do not damage the rope. The 12mm versions are chunky bits of hardware.
A series of unbelievable cock-ups by UK couriers led to Steve at Vortex and the Mastrant guys having a lot of hassle to deal with, but throughout they were gracious and tried hard to solve the issues. I found them both very good to deal with, very obliging.

Other hardware
With the three D12 guys and 6 more steel rope guys to fix up, I had an incredible amount of hardware to source. Turnbuckles of adequate size and strength, rope thimbles of three sizes, wire grips for 6mm and 8mm rope, D-shackles................
All except the D-shackles I got from Tecni-cable (sales at tecni-cable.com) - good quality stuff, prompt service and best all round prices (I think, my head was spinning with so many alternatives and permutations!) D-shackles I got from Reliance Marine (http://www.reliancemarine.com/) - best choice and price. Again very prompt and polite service.
Chris WOJ came through for a couple of days about 2 weeks ago and the job was done. I'll spare you the story but it all worked out and the result is, I hope, a more secure tower. The D12 does stretch and I have had to adjust the rope in the fist grips 3 times so far but I guess that will settle down and it is a quick and easy job.
Happy to deal with any specific question off reflector.
73 Keith GM4YXI/GM5X





The University of Aberdeen is a charity registered in Scotland, No SC013683.