blue>the Internet Archive. Yahoo! is not affiliated with the authors of this page or responsible for its content.
Amateur Radio, Paragliding and an APRS Weather Station August 2003
1
By Richard Parry, W9IF
A
mateur Radio is one of the best
things that ever happened to me.
While building transmitters, anten-
nas, electronic keyers, radioteletype
modems, APRS (Automatic Position Re-
porting System) trackers and a myriad of
other projects, ham radio provided an out-
let for my creative side and a wonderful
learning environment. My high school
days were spent installing invisible anten-
nas on the roof of my apartment building
in the Bronx, New York City and working
DX on 20 meter CW. Those times bring
back fond memories of my formative
years. Amateur Radio also provided the
spark that eventually led to my career as
an engineer. More recently, it has allowed
me to more fully enjoy the sport of
paragliding.
When I tell friends I paraglide, they
usually give me a funny look as they think
of an extreme sport. Ill admit the sport
is not for folks afraid of heights, but nei-
Amateur Radio,
Paragliding and an
APRS Weather Station
ther is it limited to the skateboarding gen-
eration. It is for anyone wishing to experi-
ence the thrill of non-powered flight. It
doesnt take a great deal of experience or
physical ability. In fact, most pilots take
their first flight within a few days of be-
ginning instruction. Paragliding and the
sister sport, hang gliding, are referred to
as foot launched sports. They literally
allow anyone to soar like an eagle and
reach for the clouds.
The Torrey Pines Gliderport in San
Diego, California, where I fly, dates back
to 1928. It is one of the premier soaring
sites in the United States. National hero
Charles Lindbergh flew there. The two-
mile ridge, overlooking the Pacific Ocean,
gives ample flight opportunity for
paragliders, hang gliders, radio-controlled
airplanes and full-size sailplanes. The
tranquil sea breeze coming off the ocean
allows flying with minimal expertise,
which makes it a great place to learn. In-
land soaring sites are also popular, but un-
predictable weather conditions require
more skill.
Paragliding allows you to enjoy a short
flight along a ridge or a lengthy cross-
country flight. Ridge soaring is possible
when wind coming from the ocean hits the
ridge and is directed upward. The upward
movement of air creates lift for flight. With
this lift, I have had many flights lasting
more than an hour. If you are more adven-
turous, you can try cross-country
paragliding where flights can last all day
and cover distances of several hundred
miles.
When my wife, Sharon, KC5PVL, and
I began taking lessons, it was not uncom-
mon to drive to the Gliderport only to learn
that weather conditions would not support
flight and we had wasted a trip. We often
stayed for hours hoping that conditions
would change but all too often they didnt.
Para-waiting is the name affectionately
Ever wonder how weather information can
be remotely sensed and displayed
anywhere in the world? W9IF shows how
an APRS weather station, an IGATE and
the APRS Internet system make it possible. 2
August 2003
given to waiting for changing weather con-
ditions. It is no more exciting than watch-
ing paint dry.
Like other outdoor sports, you are at
the mercy of the weather. However, even
when the sun is shining, the temperature
is mild and the sky is clear, it doesnt mean
you can fly. Flight requires lift. A pow-
ered airplane can generate lift anytime,
using its engines to provide forward thrust.
With sufficient speed, the uneven flow of
air over and under the airplane wing re-
sults in lift and ultimately...flight.
Paragliders do not have a power source,
so they rely on Mother Nature for lift. Tem-
perature, humidity, barometric pressure,
terrain, wind speed and direction, and nu-
merous other factors determine if flight is
possible. Being able to determine those
weather conditions while at home, via the
Internet, would be a great asset, since it
would tell us if flight would be possible.
More importantly, it would allow me (and
other pilots) to understand those weather
conditions, which would ultimately make
for safer flights.
APRSThe Perfect Solution
Weather conditions at my home, 15
miles from the gliderport, tell me nothing
about conditions at the gliderport. In fact,
weather conditions less than a mile inland
from the ocean can be significantly differ-
ent from conditions on the coast. There-
fore, to determine if conditions are
sufficient to support flight, we are inter-
ested in microclimate weather, which is the
condition within a very small geographi-
cal area. Microclimate weather conditions
can only be determined by a weather sta-
tion at the site. Unfortunately, the infra-
structure at the gliderport is very limited.
There are no commercial ac power sources
and phone lines are limited. For this rea-
son, an APRS weather station is the per-
fect solution to provide communications
from the gliderport to the local APRS net-
work and, ultimately, to the Internet, where
anyone in the world can monitor those
conditions.
I am an APRS enthusiast and have in-
stalled several APRS mobile trackers, but
installing an APRS weather station was
breaking new ground for me. It was a
learning experience with surprises and set-
backs but, in the end, turned out to be a
huge success.
The system described here has been
operational for many months and has al-
lowed hundreds of pilots to determine fly-
ing conditions remotely. The Web site is
very popular; it typically gets 200 visits
per day and sometimes as many as 400.
Weather Station Hardware
Many weather station systems are avail-
Figure 1A block diagram of the W9IF-4 APRS weather station.
able that support APRS. If you want to
build your own, the Tucson Amateur
Packet Radio (TAPR) offers the T-238, a
low cost APRS weather station developed
by Will Beals, N�XGA, and Russ
Chadwick, KB�TVJ (www.tapr.org/tapr/
html/Ft238.html). For a compact low
power APRS weather station, see
�Weather (www.rxcomm.net), developed
by K�RX. It is a single board weather sta-
tion with temperature, pressure and humid-
ity sensors located on a printed circuit
board. It also has a real-time clock and
generates 1200 baud AFSK weather for-
matted packets so a TNC is not needed; it
connects directly to a radio. Commercial
products are also available, such as those
from Davis Instruments, RadioShack, Or-
egon Scientific and Peet Brothers. I se-
lected the Peet Brothers Ultimeter 2000
(hereafter abbreviated U2K). It was picked
because of its popularity and the availabil-
ity of software (Meteorologica from
Jonathan Bradshaw, N9OXE/M1EUY) that
supports both the U2K and Linux. How-
ever, that software is not used in the
weather station discussed here. [QST re-
viewed the Ultimeter 2100, a similar, but
enhanced, version of the 2000, in the Janu-
ary 2003 issue.Ed.]
Purchasing a weather station can be like
purchasing a camera. The number of op-
tions and add-ons is staggering. A rain
gauge, sun shield and humidity sensor are
a few of the more frequently purchased
add-ons. Computer software for logging,
displaying and analyzing weather data is
also available. You can also purchase a
remote modem that interfaces the weather
station to a telephone line to allow the sys-
tem to be remotely accessed by placing a
phone call to the unit. Fortunately, for my
paragliding weather station, all sensors I
needed were included in the base configu-
ration. The U2K comes with an anemom-
eter to sense wind speed and direction and
an outdoor temperature sensor. The sup-
plied 40 foot cable connects the anemom-
eter to the control head, and the
temperature sensor comes with a 25 foot
cable. Extension cables are available, but
extending the length of the temperature
sensor can result in small errors. A baro-
metric and indoor temperature sensor is
also included with the purchase of the
weather station; both are located inside the
display console, so no additional wiring
is needed. Figure 1 provides a block dia-
gram of the key components of the APRS
weather station.
There wasnt much I could do about
protecting the weather stations outdoor
sensors from the harsh Pacific Oceans salt
air, but the electronics (TNC, hand-held
transceiver and U2K) needed protection. I
gave this a lot of thought and effort. I con-
sidered an outdoor sprinkler system enclo-
sure or a weatherproof electrical box.
Since the equipment would be inside a
small shack, however, it wasnt mandatory
that it be completely weatherproof. I de-
cided on a dustproof and waterproof cam-
era enclosure, the kind with thick foam that
can be custom cut to safely hold and pro-
tect fragile camera equipment. My intent
was to close the enclosure securely to keep
salt air out. I would also add a desiccant
to remove residual moisture. This was a
great idea until I remembered the baromet-
ric sensor is located inside the U2K. Mak-
ing the enclosure airtight would result in
false p