I figured that was why you mentioned Duct Tape. I don't like nylon
because of the extreme stretch when new. I used to use it to guy 33'
tall verticals made of 1.5" steel TV masting. If I just tied them on
and pulled the guys tight, the masts would be almost laid over on the
ground. Tighten them back up with the mast vertical and they would be
leaning 3 or 4 feet the next day, but after 3 or 4 days, the Nylon was
no longer stretchy. It was stiff and rough, but tough. I'd have a pair
with half wave spacing, with two figure 8 patterns until time to fit the
fields the next spring.
73
Roger (K8RI)
On 12/30/2015 Wednesday 8:35 AM, Patrick Greenlee wrote:
Roger, I wasn't recommending duct tape but used it as a parallel
example of something used for many more things than its original
purpose. Paracord was Nylon in its original incarnation to get the
shock absorber action desired to cushion the opening impact of a
parachute. Dacron is for when minimal stretch is desired and would be
a very bad choice for parachute rigging. I do not know if any of the
"paracord" available is made of other than Nylon. Black paracord has
more UV resistance than white (which has very little) but how
resistant I couldn't say as it could easily vary from source to source.
Walmart sells a few sizes of black Dacron line in its sporting goods
section that has proven over time to be fairly UV resistant. A hedge
against UV deterioration is to oversize the Dacron line, going
significantly larger in diameter than required to meet your minimum
strength requirements. There is nothing "magic" about Dacron as
opposed to Nylon, each has characteristics that are a fit for various
requirements.
For example (assuming sufficient UV resistance) Nylon might make a
better choice when using a flexible tree or other moveable support as
its stretchiness will allow significant motion without breakage and
will return to its original length when the wind stops blowing. Dacron
has little stretch/shock absorber action and can be more easily broken
in a situation like this. ...or it can pass significant tension (shock
loads) to other parts of the antenna structure which may be induced to
catastrophically fail. (Think slide hammer.)
For anchoring the ends of a dipole (and similar situations) I prefer
to use somewhat over-sized Black UV stabilized Dacron run through a
pulley and then connected to a weight. This accommodates motion while
keeping the same tension on the antenna components that you designed
for. It does not self destruct if a big wind moves the tree or other
components of the system around.
Patrick NJ5G
On 12/29/2015 10:45 PM, Roger (K8RI) on TT wrote:
Except duct tape ages fast and the adhesive become hard and brittle.
I use a lot, but not for exterior weather sealing of things like
matching networks. Don't purchase a lot as it ages while still in a
roll. At least what I have, has. Paracord comes in many colors, but
are any of them UV resistant? What is paracord material? Nylon? I
don't think it's poly, but could be? Anyone know?
73
Roger
On 12/29/2015 Tuesday 10:29 PM, Patrick Greenlee wrote:
Paracord is sold in many colors, from plain white (original) to OD
(Olive Drab), camo, black, etc. As duct tape is now recommended for
just about everything EXCEPT sealing ducts, paracord is used for
oodles of applications not related to parachutes. Things such as
lanyards to prevent tool loss overboard, boot laces, knife handle
wrap, snares, braided bracelets, braided keychains, and various fobs
plus a plethora of additional uses including DIY antenna
construction where black is favored for UV resistance.
Patrick NJ5G
On 12/29/2015 9:20 PM, Richard (Rick) Karlquist wrote:
It spends most of its life packed up in
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
--
73
Roger (K8RI)
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|