Rick,
Years ago there was a company in the USA that also sold a similar spreader.
I noticed in your web site the spreaders have three tines (forks). The old
units here were constructed out of some black material and had four forks. I
tried them out and they did work without adjusting tuner in rain, snow, etc.
Unfortunately, we are in an area of high wind and freezing cold rain. The
problem was these units would fail (tines broke off) in -20 degF weather
with any wind at all. Company went out of business.
Now I use 4" ceramic spacers on my ladder line. They look like 'dog bones'
and were sold years ago by Radio Shack, before they switched to polyvinyl.
The added benefit of the weight of the ceramic spacers keeps the line
from "whipping around" in the usually high winds in this area.
Regards,
de Phil - N8PS
Quoting Rick - DJ0IP / NJ0IP <Rick@DJ0IP.de>:
I changed the subject line. The thread no longer pertains to OCFD, just
Openwire.
This is a response to Robs excellent post (below).
THIS IS HOW I EASILY MAKE PROFESSIONAL QUALITY LADDER-LINE.
If interested, read on - if not then exit and delete now.
Rather than try to describe it in words, I have created a page on my web
site showing how I have been doing this for many years.
No offense guys, but IMO, this system makes the other stuff look Mickey
Mouse.
It's not cheap, but it's not expensive, and it is certainly outstanding.
When you have built your own openwire ladder-line, you'll have a
professional product for life.
The problem for most of you is, it is only available in Germany.
This is not really a problem, we live in a global economy.
The main reseller of these components is DX-Wire, my biggest competitor. :-(
Yet I buy this stuff from him and send him customers who need it.
The owner of DX-Wire and the guys here at Spiderbeam are all in the same
contest club, The Bavarian Contest Club. We've been friends for twice as
long as either of the companies have existed.
If anyone is interested and needs assistance with ordering this, I am happy
to help.
If enough interest for a bulk order, as long as we have a bit of time, I can
get this shipped to the states (Tennessee) for free (legally). I believe
there is a 6% import tax, but I am not sure.
I don't really have a chapter on my web pertaining to Openwire, so for now I
have uploaded the page to my "CATCH-ALL" section, called "Ricki-Leaks" ...
See: http://www.dj0ip.de/ricki-leaks/d-i-y-ladder-line/
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Rob
Atkinson
Sent: Tuesday, October 20, 2015 10:38 PM
To: tentec@contesting.com
Subject: Re: [TenTec] Open Wire Line - A CASE FOR OCFD
It's important to understand that any antenna is better than no antenna and
I'm speaking of incremental improvements in terms of an antenna _system_,
i.e. the matching network, feedline and antenna, and the most transfer of
power from the RF final to the load for a single system. There is rarely a
complete utter night and day difference, between two somewhat similar
systems, but an improvement will be observable over time although it might
be subtle. But a dramatic improvement, such as going from a low dipole in
town to one up 120 feet in the country will be instantly clear. In the case
of open wire line etc. it is more a matter of having a solid signal with one
antenna over several bands. With any antenna the best test is seeing how
well you can do with fairly low power, almost QRP on CW for
example. If you run enough power, a coat hanger will work, but if
you are frequently solid copy with the amplifier off, then you are moving in
the right direction.
I'd love to hear more about the practicalities of routing open wire
line from feedpoint through heavily wooded lots, through house walls,
etc etc, to the shack.
There's a rich body of literature on spacing insulators that has been
published over the years but most hams now seem to settle on either the
ceramic spacers that can be found at hamfests, or the black irrigation pvc
pipe that's about 1 inch diameter and can be cut and notched to make
spacers. The pipe has the advantage of being lightweight, but it can get
spiders and bugs in it. It seems to be UV resistant and although black, not
a known carbon conductivity problem.
The ceramic spacers were made in a variety of lengths--you use the holes on
each end to hold the tie wrap wire; the feedline wire goes on
the ends of the spacers, not through the holes. They can add a lot
of weight to the line, but over land that is okay--I'd probably go with a
light weight spacer from ground up to a free hanging feedpoint.
Most people think they need to have a spacer every two feet or so but if
the line is 3 or 4 or 5 inches apart, then once it is strung up, and has
some tension on it, the spacers can be every 3 or 4 feet, allowing more
length for the number of spacers.
If you construct your own line you get to choose what wire you want to use.
I'd consider AWG 12 stranded as it is a good compromise between power
handling and size although I think you'd have to space it pretty
far apart to get 600 ohms impedance. The top spacer at the feedpoint
should be strapped to the center insulator of the dipole so that it is
perpendicular to the center insulator and directly below it, so as to make a
X when viewed from above. then the feedline wires can be curved around and
attached to the dipole ends so there is strain relief allowing the feedline
to move around in the wind and not fatigue the connection points.
Supports over ground can be poles --the only thing that is important is that
they hold the line with insulators in the weather and maintain the line
geometry with a bit of sag but not too much, and get the line
high enough so you can get under it and/or mow under it. I have used
PVC pipe topped with T sections with light weight line.
The feed throughs depend on the wall. If you have a window with a small
pane, you can knock that out and put in a plexiglass pane drilled for a pair
of banana jacks or porcelain feed throughs, or you can drill holes for
porcelain feed throughs, -- some guys use a pair of RG213 stubs through the
wall. If the wall is stone or brick, it's harder. I'd probably route to a
window I could modify in that case.
73
Rob
K5UJ
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