Al,
Your initial thoughts sound pretty good. Several things you might want to
consider - put the "counterpoise" on the outside wall as well and feed it
against the other side of the antenna as a balanced pair. Consider replacing a
window pane with a piece of plexiglass and drill a couple of small holes in it
for feed throughs. Or drill a hole or two through the existing glass, there
are diamond-tipped bits that will do this with patience. How far are you from
the roof, and is it accessible? There is some very small diameter coax that
would work well, especially with QRP, and would not be too lossy at 20 meters
and below. You might be able to tie three dipoles together, one for each band,
and feed them with a single coax line. For that matter, if you used small
diameter wire, you "glue" three dipoles to the outside wall of the building and
feed them with a single piece of small diameter coax at the window.
Is the window frame attached to the metal frame of the building? If it's not,
don't worry about coupling to it. It would just wind up as part of the
antenna. Just keep people from touching it when Dad is on the air.
Let us know how things go.
Jim Hanlon, W8KGI
----- Original Message -----
From: Al Gulseth<mailto:wb5jnc@gulseth.net>
To: tentec@contesting.com<mailto:tentec@contesting.com>
Sent: Monday, March 27, 2006 6:53 AM
Subject: [TenTec] Apartment antenna help
Greetings all,
I'd like some "brainstorming" help on an antenna for my dad. He is on the
third floor of an assisted living apartment facility, and we've been trying
to figure out if we can get him on the air from there (even on a limited
basis). Dad has been trying some indoor antenna setups (such as the Hamstick
type dipole arrangements) but apparently to no avail. I suspect this has to
do with the construction of the building (i.e. iron frame etc.)
I have talked to the head of the maintenance department at the facility and
he
seems to be willing to work with me on an antenna, but obviously it needs to
be as unobtrusive as possible as well as require as little alteration to the
building as possible. Since dad primarily like to operate 40/30/20M, what I
am currently thinking as a solution is a 22' wire (either horizontal or
vertical) attached to the outside of the building with a bead of clear
caulking or RTV. I would need to get this through a window, so I am
envisioning using a short piece of a "sandwich" of 1/2" - 3/4" wide thin
copper strip/flashing with thick plastic tape on either side so it can
(hopefully) be formed so that the window can be closed with it in place. I
realize that there would probably be some coupling to the window/frame as it
is aluminum. The 22' length mentioned is chosen as I am of the impression
that it is a good compromise length that is easy to load on 20-40M. This
would be balanced with a 22' counterpoise along the baseboard inside and fed
via an SCG (237?) autotuner placed where the antenna comes in through the
window. (Hope I'm making sense here with all this....) Another possibility I
have considered would be something similar to the B&W/MFJ apartment antenna
but with the matching network relocated to inside the building (again
possibly using the SGC autotuner along with the requisite counterpoise).
What is the possibility of this actually working (obviously on a rather
limited basis)? Any comments or suggestions? BTW this _is_ Ten-Tec related as
dad would be using this with his Delta (probably at quasi-QRP levels of 20W
or less due to the possibility of TVI etc.)
--
TNX/73, Al
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