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1994-11-27
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IMMMMMMMMMMMMMMMMMMMMMMMMMM;
:[210 012[:
:[210Condo Communicator012[:
:[210 012[:
Subject: Condo Communications
Welcome to the seventh exciting, thrill-packed issue of Condo
Communicator, a newsletter devoted to those amateurs who, for
various reasons, must configure their stations to operate from
restrictive areas such as condos, apartments, townhouses,
neighborhoods with outdoor antenna restrictions, ships/boats,
mobile homes, or wherever they fry their burgers and call QTH.
TABLE OF CONTENTS
Soapbox........................... Page 1
Station Descriptions.............. Page 2
AA0MS
Bibliography...................... Page 2
N0OQS
It's been a while since issue #6. I've been pretty busy with
work, not to mention getting a new QRP transmitter working
(mostly) and just plain operating on the air. And, uh, my dog ate
the issue I was writing. Y-e-a-h, *that's* what happened.
SOAPBOX
You would think that the challenge in operating from restricted
space would be in the HF part of the spectrum. After all, the
antennas are large and you have to run a lot of power to be heard,
right? Evidently, not so.
From what we've seen in the first six issues of the newsletter,
putting up an HF antenna in restricted space may involve some
athletic ability, such as crawling around attics, but once there
the antennas seem to radiate well enough. Even when running low
power (under 50 watts) to minimize RF coupling into power lines or
overpowering appliances, covert operators have been making
themselves heard. Of course, these stories might have turned out
differently if we hadn't been enjoying the benefits of the great
solar cycle 22 as it peaked during 1990 through 1992.
As Lew McCoy, W1ICP, is fond of saying, just get as much wire as
possible as high and clear as possible to radiate a signal. But
as we cruise deeper into a stagnant Sargasso Sea of solar
inactivity, we may find that our modest crafts no longer will do
the job for us (talk about stretching for a metaphor...whew).
This is when covert ops either move someplace where they can erect
larger antennas or they do as the radio pioneers did and relay
their messages. Back then, they sent their messages in 30 to 100
mile hops by spark gap or CW. Nowadays, the covert operator can
put up a tiny two-meter antenna and use an HT and a computer to
connect to local, but well-equipped, packet gateways between the
VHF and HF worlds. Some communities are lucky enough to have
Page -1-
satellite gateways, like N0NBH in Denver, CO, where hams can use
low-end packet stations to communicate with satellite bulletin
board stations.
I think the most technical challenge facing the apartment or condo
dweller isn't HF or even VHF communications: it's UHF. That 30-
meter loop strung around the bedroom ceiling will radiate through
plaster and wood. But wet shingles will seriously attenuate 70 cm
or shorter wavelengths if you're shooting for a satellite.
Besides, unwieldy, high-gain UHF antennas are much more difficult
to install and operate in cramped quarters than a length of wire
tacked up on walls. A typical OSCAR array looks like an anti-
aircraft battery as it is rotated and tilted to track its targets:
who has an attic big enough for that?
So, we condo dwellers could rely on two meters for our connections
to better equipped stations, which can then in turn allow us to
connect to other stations. Or, perhaps we will use the microwave
spectrum, connecting to better equipped stations with small dishes
that can be mounted temporarily on the outside of our buildings or
on portable masts we can quickly set up in other locations.
Hopefully, people who do operate the UHF spectrum from portable or
restricted quarters will contribute notes this coming year to the
newsletter, as well as folks who have discovered various gateways
in their communities. During the coming years, as the ionosphere
becomes a poorer reflector of signals, it will be interesting to
see what ingenious strategies covert operators come up with.
STATION DESCRIPTION
Only one station desription this issue.
Doug Heacock, AA0MS, of Lawrence, KS:
Until recently, I lived in a townhouse and couldn't put up a
"real" antenna. I started with a random wire, strung from my
basement operating position, up the basement stairs and
around the corner and diagonally across my living room
ceiling. I tuned it with an MFJ 949 tuner, and did okay with
it for a while.
Later I ran coax from the basement through a couple of
closets (where the holes in the floors/celings would be
hidden) and connected it to a 40-meter dipole wrapped around
the ceiling perimeter of a second-floor bedroom. This worked
quite well for me for a long time. I seldom ran more than 50
watts from my Drake TR3, and usually it was more like 10-35
watts. Never had any problems with RFI, though I mostly
operated very late at night.
BIBLIOGRAPHY
Cleary, Jack, WN2Q. "Another Attic Antenna," The QRP Quarterly,
July 1993, pp. 21-22
Jack describes an attic-mounted delta loop for low-angle
radiation, one of the eight loops described by Doug DeMaw in
Page -2-
his W1FB's Antenna Notebook. Jack's loop is calculated for
14.060 Mhz with the loop formula: Length = 1005/F (Mhz).
Jack had a real adventure installing the antenna in the attic
of his small, one-story bungalow, including a surprise
descent into a closet, much to the consternation of his XYL.
Fun to read and great info.
Belrose, Jack, VE2CV. "An Update on Compact Transmitting Loops,"
QST, November 1993, pp. 37-40.
A great article that sums up the theoretical underpinnings of
small transmitting loops and which also compares the performance
of different types of loops. Some of the commercially
available loops mentioned are the AMA series (a German brand:
Abstimmbare Magnetische Antennen), the AEA Isoloop, and the
MFJ Super High-Q. Loops, while not comparing favorably with
dipoles on 75 and 40 meters, do compare well with mobile
whips, for example. Generally, the larger the diameter of
the loop and the diameter of the loop conductor, as well as
the greater its height above ground, the better the low-angle
radiation pattern given a horizontal orientation. How about
from the balcony of a 20-story building? The article doesn't
say.
Okay folks, let's hear from you! Send your notes, ideas, station
description, war stories, and so on to me at my packet address or:
Internet: awinterb@du.edu
US Snail: Art Winterbauer
10047 E. Mexico Ave.
Denver, CO 80231
Also, listen for snippets of this newsletter on Hap Holly's
(KC9RP) Radio Amateur Information Network (RAIN), heard on various
nets or by direct dialup (708-299-INFO, no charge except for long-
distance costs).
73,72. Art.
N0OQS @ W0GVT.#NECO.CO.USA