Don't forget, little creepy-crawly pieces of #28 ins.
wire have been known to slithery out of teeny window
sash cracks, and hang almost 3-stories to the ground.
Sometimes they sneak back inside during daylight, and
sneak back out when it gets dark. No on ever said you
HAVE to feed a 1/4 at the bottom. In fact isn't it
better to have all the feedpoint current at the top?
(That's what a bobtail or halfsquare is) You might be
able to wire some invisisble #28 around the building,
up under the eaves, etc. I would be thinking
ballanced ant systems to eliminate the grounding
delimas. But at you low pwr levels, shouldn't matter
if a gnd plane set up is used. If you need gnd plane
system antennas requiring radials, the copper flashing
would make a good solution. NOT, the kind you get
from the Ham Cos. The kind you get at Home Depot. I
got a 25' roll, 1 ft. wide, for $22. Used for my
Station gnd connection. But now I'm geting other
ideas. So many uses. You can cut that into strips
and have 300-400 feet of 1 inch wide radials, for
instance. Portable, stealth or high performance
applications abound. One side is mounted with
protective paper glued on. You could have it on the
wall with paper side out and paint it. Some sheets or
strips tucked under the rug or wall mounted can give
you a pretty solid gnd plane. What about voltage fed
antennas, those fed at the high voltage end, like a
bobtail for instance? Whereas gnd planes need lots of
longer radials due to the current point they are fed
at, high voltage feeds require only very sq. ft. of
screen or solid plate for a radial systems, to achieve
the efficiency of 120 full sized radials of their 1/4
wave gp counterparts. Even a 4'x 4' piece of chicken
wire will make a sufficient gnd plane for an antenna
fed at the voltage maxima. I would think that a x
(cross) out of the copper flashing from 1' wide, you
should have a good high voltage gnd. Supplement it a
little where you can and maybe connect all the ends of
the cross with a small wire. I'm thinking a half wave
of wire here, with a few feet square for ground
screen. To match it, #12 bare wire, wound around a
piece of pvc pipe or such and then pulled off for your
air inductor. Center wire of coax taps along this for
the proper match, with the propera coax length cut for
your high voltqage capacitor, gives you a 50
feedpoint. The bottom of inductor, and coax braid, go
to you ground screen ":ground" I have a site I can
send to calculate the length of coax to cut for the
High Voltage cap, and number of coil turns to use for
various freq. I can post if you would like. I like to
use a PVC electrical connection box, which coe with
four screws and a rubbergasket, to house the thing.
It can be mounted just outside window (or just inside)
Once you've found the proper tap, seal it up. These
can be had for 2-3 dollars at Home Depot. Very
affordable antenna system, and can be built to handle
any power level up to a KW. Then you've got hatted
dipoles, Horiz, and vert., with sheets of copper on
each end, say one on the eave, one on the ground---but
that;s a different story. Well, that's my .02 worth
73s and happy stealthing. Don't let the bastards keep
you down!
--- NJ0IP <Rick@DJ0IP.de> wrote:
> Al,
>
> My uncle was in the same situation, living on the
> ground floor of an
> assisted living apartment. He was not allowed any
> outdoor antenna.
>
> I built him a magnetic loop antenna for 40m, using
> parts I bought from the
> Home Depot, plus purchasing new coax for the loop.
> Since he only wanted one
> band, I used a fixed capacitance made of coax to
> tune it to the band and
> then built a tiny 'gimmick capacitor' using two
> pieces of the inner
> conductor of the coax placed in close proximity of
> each other for the fine
> tuning. He tuned by adjusting the gimmick capacitor
> (without power applied).
>
>
> How did it work? Well, living in Oklahoma, he was
> able to consistently
> check into his daily net for his rag chews and work
> around the Midwest with
> a good signal. He only worked SSB with a 100w rig.
>
>
> In the meantime MFJ has come out with a new magnetic
> loop antenna that also
> tunes 40m. If I had known that at the time (January
> 2005), we would have
> simply bought that instead of building.
>
> You read all kinds of reports about these antennas,
> both good and bad. Of
> course you can build something outdoors that works
> better, but this is
> beyond a doubt the very best indoor antenna you can
> use and it is probably
> just as good as a make-shift compromise antenna -
> though a couple of s-units
> down on a good dipole.
>
> If you want I can send you pictures of the loop I
> built for him.
>
> 73
> Rick
>
>
> -----Original Message-----
> From: tentec-bounces@contesting.com
> [mailto:tentec-bounces@contesting.com]
> On Behalf Of Al Gulseth
> Sent: Monday, March 27, 2006 5:53 AM
> To: tentec@contesting.com
> 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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