[TowerTalk] C4 -- Wow

[Jim Reid]

It's up in the air.   Thanks to the rock climbing team along with their
carabiners, pulleys,  long colorful ropes and their experience in
dealing with things up in strange places!  Also got a lot
of help from Tom Schiller's book, "Array of Light",  in which
there are many fine illustrations of how to handle yagis
going up and down the tower,  along with rope use hints,
use of lifting loops,  etc.  All was used,  and then some 
tricks the climbers use on the rocks.

In three hours time,  the old Mosley TA-34 was on the ground
and disassembled (to get it out of the way),  and the C4 was up
together with a 33 foot tall aluminum whip(Gladiator vertical) which 
goes on up to about 83 feet or so.  Intended for antenna diversity
reception input to the BPF-1 of the FT-1000D.

I am especially pleased about the resulting tuning and
apparent 40 meter performance.  On 7 MHz,  the EF-140S
element wound up resonant just a bit lower than
my target of 7040;  using my MFJ-259B analyzer
at the end of 160 feet of coax (70 feet of LMR-400
coming down to ground level,  plus 90 feet
of LMR-900 to the shack) resonance occurs
at 7015m  with an swr of 1.3 (R=69 ohms);
at 7008,  X is still zero,  R is 62 ohms,  and
the swr is 1.2:1.  Not bad for estimating the
tuning element placement and guesstimating
the spacing of the hairpin match coil turns;
and no,  I'm not brining the whole thing down
to change anything  -- at least not now!

On the Hawaiian afternoon net yesterday,  at
7088 MHz,  the gang was astounded by the
change of my signal strength from the day
before:  from at the noise  or  just above,
to reports of 9+10 to 25 from Oahu,  and 
9+20 down on the Kona side of the Big
Island about  275 miles SE of my QTH
here on the South side of Kauai.  Now
the previous antenna was essentially
a dummy load I suppose:  my TL160 meter
vertical,  with all of the 160 meter radials
removed,  and with a single 33 foot long,
elevated 40 meter radial,  hi.  Tuned up,
of course with my antenna tuner in the
shack. (I have to have the TL160 down
this coming week,  the horses are coming).

The C3 part of the antenna was riveted together
exactly as described in the manual, using the
center rivet holes on 15 and 10.  I would change
those now,  but it is not worth it to me to have 
the climbing gang back just for that.  So here
is how all measure up (no operating results,  as
yet,  just measurements using the 259B):

20 Meters, excellent measurements:

Resonant at 14160, X=0,  R=57ohms, swr=1.1
14001,  R=37, X=8,  swr=1.4
14348, R=54, X=15, swr=1.3

15 Meters,good,  but probably should have
made the elements one rivet hole longer
to favor the CW band more,  but no problem
using the AT4K antenna tuner:

Resonant at 21155, R=36, X=2, swr=1.3
21000, R=23, X=7, swr=2.2
21450, R=21, X=15, swr=2.7

10 Meters,  again ok,  but wish I had made the elements,
probably two rivet holes longer to favor the CW band:

Resonant at 28500,  R=35, X=0,swr=1.4
28000,  R=16,  X=6, swr=3
29,700,  R=90, X=87, swr=3.4,

and again, no problem using the AT4K 
tuner,  and not getting into too many situations
where rapid QSY's are needed.  I only contest
casually,  hi.

So there you have the results by meter and one
set of local reports on 40.  More to come including
comparisons to my set of 1/2 wave,  center fed
vertical dipoles.  Have one quick note on that.
That 33 foot whip I mentioned on the tower top,
has one 33 foot long wire coming down toward
the ground.  Now it is not out too far from the 
grounded tower supporting everything.  And on
both recv and xmit,  the vertical,  on 40 is at least
1S unit down from the EF140S dipole and, more
often than not,  2 S units down.  That is disappointing
after the effort put in to get that thing way up there
in the air by the climbers -- took two of them up there
to handle it and bolt in place!  Maybe that is just another
demonstration of the dissatisfaction of many  with
verticals,  even real half wave ones;  or maybe it is
because of he proximity of the grounded tower
near the downward leg of the dipole.

73,  Jim,  KH7M



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