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
|