Hi Richard and the group,

Excellent. I can even move the 5th mast out to add even more perimeter. The
clearance at each mast will be at least 10'-15' maybe more. Your keyboard image
making was appreciated.

Did I mention that the ladder-line will be perpendicular, but moving away from the
loop more horizontally than as a strict vertical drop. The ladder-line will be
10-20' away from the mast at that corner and needs to span maybe 45+' to the house
and then maybe another 15+' feet to the matchbox. I only mention this in case I am
overlooking any precautions I may have not already considered.

It looks like the loop will have to have a bit of tension in order not to droop,
especially with these dacron extensions at each mast. I was planning to have the
loop wire free-flowing at each corner glass strain insulator (glass can handle the
abrasion, plastic could not), except the one corner closest to the point where the
ladder line-attaches in order to minimize movement at that feed point juncture.

Most of the mast materials are set to go. I still need to decide on the details of
the ladder-line construction, which wire and which spacers. I will use solid copper
wire because braided is too wiggly and might swarm at me. Insulated vs. bare? Bare
has a certain appeal. #14 vs. #12 vs. #10 (?).
Why not #10?, it is only in the air for 45'....ok maybe that is a bit heavy, a bit
overkill, maybe #12 then.... anyone ever use #10 for ladder line?


I am thinking that bare #10 (or even #12) solid copper would hold its shape
especially negotiating the curve from the 4' of PVC pipe it will be tied to above
the house at the edge of the roof peak, then arching down and crossing between some
telephone and cable tv lines, into the the side of the house through some porcelin
insulators, suspended briefly in the attic, and then down through the ceiling, again
through porcelin tube insulators. In other words, after I poke the two wires through
the side of the house into the attic, I will, shortly thereafter, be up in the attic
continuing to attach a number of spacers to these wires (wearing a dust mask and a
cob-web proof hat), until I get to that point in the ceiling where the wires will
again go through the porcelin insulator tubes, then on the other side of the ceiling
(in the "shack"), as the wire comes into the station, I will again be adding a few
more spacers until it arrives at the matchbox, at which point, I will have a coffee
break.

This way the ladder line will have no breaks from the antenna feed point to the
matchbox.

hmmmmm....what if I need to add length to my ladder-line later for some reason? I
will hate to cut into it!


Does 60-65' of ladder line seem like a "good" number. I will double check this
meaurement tomorrow. If anything, it might be longer. Are there any particular
lengths in this type of feed system I should be avoiding? BTW, the matchbox has no
160m. Until I acquire some other balanced tuner that does, if I want to try this
loop on 160m, I will have to connect it to a little balanced tuner I have here using
a balun.

I have learned that a good technique for tying the ladder line to the anchor above
the roof's edge is to weave some of that small dia. dacron line into each side of
the ladder line and use that to pull the ladder line to the support. Anyone second
this, or have another solution? Pulling on the spacers doesn't seem like a good
idea.

If I have stated anything that needs advice or correction, anyone, please don't
hesitate.

73

Bill



Richard Clark wrote:

On Mon, 19 Apr 2004 00:35:21 GMT, zeno wrote:
But this does still leave the metal mast in the proximity of
these corners, so the question is: how much more of a problem (corona etc.) is
adding metal wire guys to an already existing metal mast. My simplistic
intuition is, the more wire at more angles in the vacinity cannot help the
situation. So unless I hear otherwise, I guess I will plan to use the dacron for
the guys on all masts.

Goferit.

The answer to proximity (seeing you have more perimeter than you need)
is to simply keep the corner off, away from the mast about 10 or 20
feet. In other words, you put the masts at corners that are well
outside the bends of the loop. Thus you are suspending the loop bends
with dacron line (through the pulley) such that THOSE bends are well
inside the box described by the mast co-ordinates. (Think box inside
a box co-ordinate system. The exterior box corners, the masts,
support the interior box corners, the antenna.)
View with fixed font:

M---------------------M
|\ /|
| \ / |
| ................. |
| . . |
| . . |
| . . |
| . . |
| . . |
| . . |
| ................. |
| / \ |
|/ \|
M---------------------M

where
M is mast
--- is a ghost line
/ or \ is dacron going to antenna wire
... is antenna wire

You have the flexibility to put acreage to work for you, don't try
passing the bends through AT the mast itself.

73's
Richard Clark, KB7QHC