On Sun, 11 Dec 2005 06:06:08 GMT, Owen Duffy wrote:

On Sun, 11 Dec 2005 05:39:27 +0000, Wes Stewart *n7ws*@ yahoo.com
wrote:


I wasn't going to go that far, and I realize it's probably not common
in ZL but I've bought lengths of LDF5-50 at ham flea markets. The
last purchase, claimed to be about 10 meters worth, but by my
estimation at least twice that long, and new and unused, cost me $10
U.S.

Most of this stuff is leftover or removed from commercial two-way or
cell phone use and shows up all of the time. LDF4-50 is even more
common. I often buy short pieces that have been cut down, just for
the connectors that are still on one end.

I find it curious that Andrew cable is seen so often at these events
and yet I've -never- even seen a piece of Davis cable, dispite the
claims that miles of it are in commercial use.

I agree with Ian's comments, the larger sizes are often available here
as they are less attractive to hams. But if you buy 3 or 4 lengths of
LDF5 or LDF6 and use connectors to join them, you will run into big $
unless the connectors come very cheap.

I have a ham friend who uses long runs of coax to his several towers.
He is a big gun on 80 and 160 meters, so this mainly applies at m-f to
h-f. He uses a lot of LDF5-50 that he obtains in shorter pieces.

His technique, as he briefly described it to me, is to -not- use
connectors but splice the lengths directly. The center conductor on
these cables is hollow, so he inserts a short length of brass or
copper into the ID and solders it in place.

I don't know whether he adds any insulation next or not, but I would
envision injecting some low-expansion spray foam later. He then wraps
the outer conductor with brass or copper foil and solders this in
place. (Here is where I would inject the foam.)

This is then wrapped with tape for protection. I would use a double
layer of #27 3M tape with an overwrap of plastic electrical tape.

To strengthen the joint mechanically, he straps on a length of steel
angle using stainless hose clamps. For lines on or in the ground this
stays in place. For runs up the tower, after the line is in place,
strapping to the tower is sufficient support.