Hi, gang:

Just moved into a "Townhouse" and am now stuck with doing the invisible
antenna thing... I need some insight. Please read:

My 4-plex has four side-by-side units, each with a ground floor plus an
upstairs (plus a hard-to-access upstairs attic space). Looking at
things from the backyard, my unit is on the left. After thinking about
various solutions for a few months, I decided that the cheap-n-dirty
approach was to load up the 75-foot horizontal run of seamless gutter,
which runs from east to west. It's about 22 feet above the ground and
runs the length of the common roof line. My shack is on the ground
floor about 15 feet from the left-hand downspout. With me so far?

To keep things sneaky and to get a better electrical connection to the
seamless gutter, I crawled out the bedroom window onto the garage
roof...and used a stepladder to climb onto the main roof (yes, at
night, of course!). Surviving that, I used an electrical "fish wire" to
drop an 18-gauge insulated wire to ground level INSIDE the downspout.
Up top, the wire runs horizontally inside the gutter for about 15 feet,
where the peak of the garage roof (easy access) puts the gutter at eye
level. At the "feed point," about 15 feet into the 75-foot horizontal
run, I sanded off the protective coating on the inside of the gutter,
drilled a small hole for an 8-32 stainless screw and attached the
antenna wire via a soldered lug. I cranked everything down tight and
sealed it with silicone for WX protection.

At ground level, the downspout sits a couple of inches above my side
door patio slab, so I positioned an empty outdoor hose reel/box to the
left of the spout (looks natural and doesn't draw any suspicious
glances). Inside the hose box is my SGC autocoupler, which is connected
to the wire coming out the downspout (can't be seen without a
microscope) and a 1/4-wave counterpoise for each band from 80 through 6
meters. The counterpoise wires, made from 24-gauge enamel-covered motor
wire, are bundled together and run around the foundation slab to the
north and are hidden by the decorative rock that circles the condo,
etc. Also buried in the rock and butted against the slab is a 25-foot
run of RG-8X coax, bundled with a length of the same wire I used for
the antenna (to power the autocoupler). The downspout is essentially in
the center of the building on the north-south axis. The counterpoise
goes north and bends around the building to the east while the coax
runs to the south and enters the attached garage just above the floor
slab. (I converted the attached garage to my office/shack.)

Okay. So I have a 95-foot inverted-L, with 22 feet being vertical, the
rest horizontal, worked against a counterpoise system. Not a Steppir
Yagi at 200 feet...and not a horizontal loop at 50 feet...but better
than a sharp stick in the eye...

QUESTION 1: The downspout has several angled, press-fit sections and,
under these circumstances, I'm always worried about nonlinear
rectification. Do I connect the bottom end of the downspout to the
antenna wire at the autocoupler level...or do I let the antenna wire
float inside the downspout...knowing that they're electrically
connected (via press fit junctions) to the seamless gutter up above? If
I don't tie in the bottom of the downspout, will it "shield" the wire
inside or act "strange" with the autotuner? And what about nonlinear
rectification? I can only connect the bottom of the downspout. The
upper angles and bends are essentially inaccessible.

QUESTION 2: I can optionally run a second pair of counterpoise wires to
the south (40 meters and up - no 80), but the wires will have to be
bundled with the RG-8X coax, which runs to the shack. Could there be
any potentially bad interaction between the second set of counterpoise
wires and the feed line? Coupling? Inductance? RF in the shack hassles?
And if that's NOT an issue, is a second set of counterpoise wires going
to make a noticeable difference in antenna performance?

I mostly run 100 mW to 10 W, CW and RTTY/PSK. I sort of planned to
avoid SSB in case I'm messing with someone's clock radio down at the
other end of the building I'm in the process of trying to find an
IC-703 or an Argonaut of some sort (sold all radios a year ago...long
story), but if I can only acquire a 100-W rig, I might be tempted to
run 100 W on rare and desperate occasions (to work the Sultan of
Bhutan, or whatever

SUGGESTIONS? COMMENTS?

All are welcome, of course!

--Kirk, NT0Z

SUGGESTIONS? COMMENTS?

All are welcome, of course!

--Kirk, NT0Z

Whatever you can get to work - just do the best you can. I was in the same
situation in a condo,
although I was on the 3rd floor. I tried loading the gutters, but got very
poor performance. I ended
up with just a 30' run of 26ga enameled wire run from the bedroom window out
to the eaves under
the balcony, and that worked great. But I was running a Drake C-Line (this
was in the year 2000)
and had lots of power. I worked all over the US and some DX on 40 and 20,
with a Kenwood
TS-180 manual tuner. QRP would have been a very different story. I only
run CW, so didn't
have any experience with SSB. I'm sure I was lighting up something in the
building, but never got
complaints (of course, no one knew I had an antenna!) and only ran late at
night on 40 and in the
middle of the day (when folks typically aren't watching TV or even at home).

If you get a good sharp dip at resonance with your tuner, you will probably
not have a lot of
interference problems. But if the tuning is 'mushy' and very low Q, watch
out! You're probably
not getting out, and just swamping the house with RF. Be sure to employ a
good LP filter as well.

I wouldn't expect much QRP performance, especially at 100 MW!

Just give it a go and see what happens.

Dave WB7AWK

Heck, he should be heard gangbusters with 100 MW...100 mW might be a
different story!

Sorry, couldn't resist...


Scott
N0EDV

Zommbee wrote:

SUGGESTIONS? COMMENTS?

All are welcome, of course!




I wouldn't expect much QRP performance, especially at 100 MW!

Just give it a go and see what happens.

Dave WB7AWK