[RSM] "The Magic is Back"

[Art Boyars]

Here's a story (alternate title: Art's Adventure in Antenna Land) that I
shared with PVRC after the ARRL DX SSB 'Test back in March.  One RSMer
thought the rest of you might enjoy it.

73, Art VE4VTR/K3KU
=================
At the end of the ARRL DX Phone Contest I thought the title of my report
was going to be "The Magic is Gone" -- gone, that is, from my antenna, a
200-ft-long tree-supported dipole, with each end of the antenna running
down about 25 feet.   The support trees are in the neighbors' yards on each
side -- no trees left in my yard after the old tulip poplars started coming
down.  The feedline is about 75 feet of ladder line, with 50 ft of RG-213
to make a "balun choke" coil and go through the basement wall and connect
to the rig.

The "magic" is that, with plain luck and no planning, the autotuner in my
TS-850SAT can match the antenna on all the contest bands.  The magic
depends strongly on feedline lengths (no surprise), so whenever I rehab any
part of the feedline I carefully duplicate what it used to be.

The antenna gets a lot of up-down movement when the wind blows the trees,
and from time to time the ladder line breaks right at the connection to the
antenna.  I like to lower the antenna every year or two and check the
feedline; the autotuner can mask a lot of defects.  However, for a year or
more the insulator on one end of the antenna has been snagging on something
in its tree and I have not been able to lower that end of the antenna.

On Sunday afternoon of ARRL DX CW (two weeks ago) the WX turned nice, so I
stopped operating to work on the antenna.  I managed to unsnag the
insulator and lower the antenna.  Hooray!

Checking the feedline continuity is always tricky because I am only 3 Km
from a 50KW AM broadcast station on 1500 KHz.  Just holding the
ohmmeter's leads up in the air gives all kinds of weird readings.  But I
tried enough things -- including shorting the ladder line where it connects
to the coax going through the basement wall -- and satisfied myself that
all was OK.

Then, when I tried to haul the antenna back up, that same insulator got
snagged again; it would not go up.  Argghh!  QRT.  I managed to take up
enough slack in the other end to get the antenna and feedline safely above
head height, and began pondering what to do.  Last resort would be to
launch another line over the tree, but that's iffy, too.

Last week we got another break in the WX.  I had figured out a few things
to try, so I went out into the back yards to give it a go.  My clever ideas
worked.  I got the antenna back up, and came happily into the shack to
check that it matched OK.

Arrrgh!  It hardly matches anywhere.  Stand down for a while to cogitate.
Maybe I trimmed the antenna differently.  Maybe the feed line is open after
all.  I have no good ideas.  Sunday afternoon of ARRL DX SSB I decide to
try making a few QSOs, expecting I can work some SA and Caribbean on the
high bands -- if the antenna will match well enough.  Nothing heard on
10M.  On 15M I work four stations in the Brazil QSO Party and one ZP.  I
drop down to 20M and nab a CT3 and a Portugal.  That's enough.

Monday after the Contest I try adjusting the antenna trim -- pull one end
down a little farther, let the other end up a little, make sure the feed
point is in the same position it used to be in.  I compare the position to
the barely visible pic of the antenna over my house on Google street view.
All looks right, but it still won't match.

I decide to replace the ancient ladder line.  I've experienced intermittent
broken wires inside the insulation up by the feed point.  The insulation is
starting to look kind of faded and brittle.  Time for a feedline
transplant!  I grab a sample to take up to Joel at the RF Connection to buy
some replacement.  To make sure I'll get the right stuff I take a look at
the ladder line where it connects to the wall-penetrating coax, and I see...

MY CLIP LEAD SHORTING THE FEEDLINE !!!.  I had forgotten to disconnect it
after checking the continuity a couple of weeks ago!

I unhook the clip lead, go back into the shack, and check the antenna
matching.
YES-S-S !!!

Well, it's far from the dumbest thing I've ever done, and no ultimate
harm.  Amazingly, I made those seven DX 'Test SSB QSOs loading up a two-ft
short circuit.

I think I'll replace the ancient ladder line anyhow, but I'll be careful to
make it exactly like before.

QRV, and CU in the Test.

73, Art K3KU
100W and a Magic Dipole