40 Meter "STEALTH" VERTICAL
*I have since moved to a new location, and no longer have this antenna, however the information may still be helpful to someone who has a similar situation as I was in*
Now you see it.....
Now you don't!
I live in a nice
community, very quiet and safe, with good schools for my son, and close to where
my wife and I work. There is a down side however: homeowners
association. They are quite strict, and antennas are DEFINITELY not
allowed. Although I primarily operate contests as a guest operator, A.K.A.
"hired gun", it is nice to have a home station where I can play in
between contests. With a little thought I developed and installed a very
effective antenna which is quickly raised at night and is completely invisible
by day when lowered.
Originally, the antenna was made from aluminum tubing.
I have since replaced this with a MFJ fiberglass mast. Not only did this
cut down on the weight dramatically - from 20Lb to less than 5Lb - but it also
gave me multi-band capability. Running up the length of the mast are three
#14 stranded wires, equally spaced around the mast. They are secured to
the mast with electrical tape along the entire length. Each wire is cut to
be resonant on a different band - for 40, 30, and 20 meters. I started
with the standard 1/4 wavelength piece of wire, but had to cut about 2 feet off
the 30m and 20m sections in order to bring the resonance to the correct
frequency, due to proximity with the 40m wire. The three wires are
connected at the base of the mast and are fed with normal 50 ohm coax.
The vertical is fed against a substantial radial
system. A total of 60 radials are laid on the roof, each made from #18
stranded soft drawn copper wire normally used for grounding hanging light
fixtures. Each radial is at least a 1/4 wave on 40m in length. This
wire can be purchased from Home Depot. Although the wire is bright and
shiny, it quickly tarnishes into a dull brown color when left in the weather
(make sure the solder the wire to the ground point BEFORE it weathers otherwise
you will not get a good connection!). The wire is completely invisible
from the ground level as it blends in perfectly with the roof. The ends of
the radials are tucked under shingles to keep them laying flat. All 60
radials are connected to a single point, attached to the gutter and the aluminum
framing of the screened in porch, which adds to the system.
Attached to the porch framing is a 1/4 inch piece of
aluminum. To this a 1" piece of starboard is attached with a
3/8" bolt, large flat washers, and nylock nut (to prevent it from coming
loose). This bolt acts as the pivot point of the mast. Starboard is
a plastic product used often in the marine industry for console
fabrication. It is a very nice material to work with - very strong, and
can be cut/drilled just like wood. It's insulating qualities make it
perfect for my use. The mast is attached to the starboard with U-bolts
with the mounting nuts countersunk into the starboard so they will not catch
onto the aluminum plate during raising/lowering. When the antenna is
raised, another 3/8 bolt is pushed into a hole drilled through both the
starboard and aluminum to keep it in a vertical position. A small U clamp
is used to hold it in place if it is windy out to keep the whole thing secure.
How does this antenna work? It works very well on 30,
20, and 15 meters (the 40m wire is also resonant on 15). The antenna
really performs on 40m however. I really feel LOUD on 40, and on-the-air
tests have proven this. In fact, there have been times where I have been
as loud into Europe as W4AN with his full sized 3el monobander. I easily
work Asia long path, and usually can break any pileup in one or two calls.
VU, EX, EY, 4L, UA9's....its all easy. I often receive outstanding signal
reports. I have worked 40m WAZ twice over so far in the past year with
this antenna. Not bad for a stealth vertical!
Although the antenna is a real player for DX, it does not
perform
as well for local continental QSOs. That's a result of the extremely low
take off angle of the antenna.
