Just put the finishing touches on my modified K1WA 50MHz sloper array.
The is my *VERY preliminary* description and performance report.
Mods to the 'HANDBOOK' model include:
-Band is 6M not 40M.
-4 slopers instead of 5 (so far anyway)
-Using RCS-4 antenna switch (no control cable to fool with) instead of HB
-The 4 dipoles are oriented around a 10' peice of 3/4" PVC mast (instead of
a tower) and instead of sloping down at a constant angle, I have a
horizontal "X" 1/2-way up the PVC mast made of small 3/8" PVC tubing from a
garden center. I attached each dipole end using fishing line to the
top/bottom of the main PVC mast, and attached the homebrew center insulator
to the very outer tips of the center X.
>From a sideways view the slopers are a sideways V-shape, not a slanted line
running @ 60' or whatever.
The tips of each sloper are about 8" away from the ends of the 3/4" vertical
PVC and about the same from each other.
The center of each sloper is about 5' from one another. Sideways view is
kinda like this:
The whole mess roughly looks like a 3D diamond shape (does that make
I stuck the bottom of the array on a 8' piece of pipe in a hurry (0degrees C
and raining here-BRRR), connected
50' of RG8 and tossed the coax in the window. No time to fish wires in the
The SWR is higher than I would have thought. With a single sloper on the
"cage" I built, the SWR was nearly flat
from 49.5MHz-50.5 MHz, but now it's 2.1:1 or higher. Must be too much
interaction--I'll play with that a bit.
I used 3/8WL coax feeders of RG8X per handbook.
I have the thing oriented so I cover NE/NW/SE/SW. Only judging from my 6M
bcn, VE9MS/B on 50.0655MHz
25 miles away and the local Baby monitors, TV coloburst Xtals on 50.113 and
the like, I have "guessed" the gain is roughly 3-6dB and the F/B is
somewhere around 20dB (or maybe better).
Like I said, prelim report---interesting nontheless. Sure will save on rotor
wear and tear during 6m openings.
I had thought of putting a length of vertical wire alongside the center 3/4"
PVC support as an added "center"
reflector. This way each "driven" element would see a trigonal reflector all
in one straight line (+ the FAR reflector
way behind) instead of the odd shaped reflector pattern it sees now. Will be
interesting to see what, if anything
this does to SWR,PATTERN & possibly GAIN. In the 40m array in the handbook,
no mention is made of this, but then again, the 40m version is mounted
around a metal tower, whereas the only metal mine sees is the RCS-4 relay
below the center -X
Once I get some good WX, I am going the hoist the whole affair into the air
using pulleys and rope between 2 of my towers to about the 35' level , which
should be adequate as a (mostly) RX antenna on 6m.
7 3 de Mike VE9AA dit dit
Michael, Coreen & Corey Smith
(VE9AA, VE9AAA & Little-VE9 to be)
271 Smith Rd
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