[CVRC] The ARRL Letter for July 1, 2010
ARRL Web site
memberlist at www.arrl.org
Thu Jul 1 17:52:51 EDT 2010
If you are having trouble reading this message, you can see the original at:
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July 1, 2010
Editor: <mailto:k1sfa at arrl.org>S. Khrystyne Keane, K1SFA
<http://www.arrl.org/>ARRL Home
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* + Public Service : WX4NHC, VoIP Weather Net
and Hurricane Watch Net Activated for Hurricane Alex
* + Amateur Radio in the Classroom : ARRL
Teachers Institutes Wrap Up in New Mexico, South Carolina and California
* + ARRL Field Day : It's a Wrap!
* ARRL in Action : What Have We Been Up to Lately?
* + The Doctor Is IN : D-STAR, Antennas and Amplifiers
* + Solar Update
* + ARRL to Close in Observance of Fourth of July
* This Week on the Radio
+ Available on <http://www.arrl.org/arrl-audio-news>ARRL Audio News
+ Public Service: WX4NHC, VoIP Weather Net and
Hurricane Watch Net Activated for Hurricane Alex
Hurricane Alex -- now once again Tropical Storm
Alex --closes in on land near the Mexico-Texas
border on June 30. Alex is the first hurricane of
the 2010 season, and the first June hurricane
since 1995. [Photo courtesy of NOAA]
As Tropical Storm Alex turned into Category 1
Hurricane Alex, three Amateur Radio mainstays
during the Atlantic hurricane season -- WX4NHC,
VoIP Hurricane Net and Hurricane Watch Net --
activated at 8 AM EDT on Wednesday, June 30;
WX4NHC is the Amateur Radio station at the
National Hurricane Center in Miami, Florida. Alex
made landfall at Soto la Marina, Mexico late
Wednesday, but weakened Thursday as it moved
across Mexico and was downgraded to a tropical
storm, dumping heavy rain over Mexico and south
Texas; the storm's center made landfall with 96
MPH winds in San Fernando in the Mexican state of
Tamaulipas, 75 miles south of the Texas border.
According to the NHC at 11 AM EDT Thursday, Alex
was centered about 165 miles west-southwest of La
Pesca, Mexico, and about 150 miles east of
Zacatecas and was moving west at 12 MPH; it is
expected to stay on that trajectory for the next
day or so. Read more
<http://www.arrl.org/news/wx4nhc-voip-weather-net-and-hurricane-watch-net-activated-for-hurricane-alex>here.
+ Amateur Radio in the Classroom: ARRL Teachers
Institutes Wrap Up in New Mexico, South Carolina and California
Many Teachers Institute participants find
programming the BOE-BOT to be challenging, yet
extremely fun. [Sam Gray, Photo]
After the first ARRL Teachers Institute on
Wireless Technology (TI) of 2010 concluded this
past February in Tucson, Arizona, three more TIs
happened in quick succession -- New Mexico, South
Carolina and California -- in May and June. The
Teachers Institute on Wireless Technology is a
four-day, expenses paid in-residence learning
opportunity designed for motivated teachers and
other school staff who want to learn more about
wireless technology and bring that knowledge to
their students. A variety of topics are covered
during the TI, including basic wireless
technology literacy, electronics, the science of
radio, radio astronomy, how to bring space into
the classroom ham radio operation, introduction
to microcontrollers and basic robotics.
Participants do not need to have an Amateur Radio
license to attend a TI session. The Teachers
Institute program is one component of the grant
offerings within the ARRL's Education and
Technology Program portfolio of resources made
available to schools and school teachers to
advance the integration of wireless technology
literacy and ham radio into school curricula.
Read more
<http://www.arrl.org/news/arrl-teachers-institutes-wrap-up-in-new-mexico-south-carolina-and-california>here.<http://www.arrl.org/nladclick.php?n=al&t=i&i=2010-07-01&p=0>
+ ARRL Field Day: It's a Wrap!
W1AW Station Manager Joe Carcia, NJ1Q, operates 6
meters on Sunday morning during Field Day. [Pete Gloistein, KC2PJH, Photo]
With more than 500 Field Day logs already
received -- and more coming in every day -- it's
safe to say that this year's ARRL Field Day was a
smashing success! Conditions, at least on the
East Coast, were quite good. Operators at W1AW,
the Hiram Percy Maxim Memorial Station, worked
almost 3000 stations during Field Day, including
a few California stations on 6 and 10 meters, as
well as North Dakota on 10 meters on Saturday.
Don't forget to send in your Field Day logs. Logs
for 2010 ARRL Field Day must be postmarked,
<mailto:fieldday at arrl.org>e-mailed to the ARRL,
posted to the <http://www.b4h.net/cabforms/>Field
Day Web Submission Applet site or submitted by
2059 UTC Tuesday, July 27, 2010. Late entries
cannot be accepted. You can also post your Field
Day stories and photos on the
<http://www.arrl.org/contests/soapbox>Field Day
Soapbox. The 2011 ARRL Field Day will be June 25-26.
ARRL in Action : What Have We Been Up to Lately?
This feature -- including convenient Web links to
useful information -- is a concise monthly update
of some of the things ARRL is doing on behalf of
its members, including advocating for Amateur
Radio operators at the national and international
level, instructing classroom teachers on wireless
technology, activating W1AW for ARRL Field Day
and more. This installment covers the month of
June. Read more
<http://www.arrl.org/news/arrl-in-action-what-have-we-been-up-to-lately-23>here.<http://www.arrl.org/nladclick.php?n=al&t=i&i=2010-07-01&p=1>
+ The Doctor Is IN: D-STAR, Antennas and Amplifiers
Tom Copley, K4YAZ, finds that he needs to use
more power to consistently reach my local D-STAR
repeaters in the Tampa Bay area. I live in a
condo and my VHF/UHF antenna is on a second floor
porch. Moving it higher or into the clear is out
of the question, due to my condo association. I
am using a dual band transceiver with 50 W output
on high power. This is not enough to consistently reach the local repeaters.
Since I am mainly using the 70 cm band, I have
purchased an amplifier that has an output of 100
W with 30 W drive on 70 cm. The amplifier also
has a useful receive preamp. To obtain the full
100 W output from the linear, one must input 30
W. My 50 W radio would be over the input rating
of my linear, and the approximately 15 W output
from the radio on medium power will not drive the
linear to the full 100 W output. Is there an easy
solution to this issue, or do I have to get a different amplifier?
Here's what the Doctor had to say:
If you are right on the edge of the coverage
area, the 3 dB increase in power may make the
difference. Also consider any other losses, such
as in the coax run to your antenna -- at 70 cm,
coax loss can be a big factor, and if the length
is more than a few feet, better coax may reduce
loss by almost as much as the amplifier gain -- get every decibel you can.
Figure 1
Your amplifier drive problem turns out to have an
incredibly simple solution. If you have 2.2 dB
loss between the radio and the amplifier, your 50
W radio output will be just 30 W at the
amplifier. This only makes sense because of the
preamp in the amplifier; otherwise, the loss
would also reduce receiver sensitivity. With a
preamp that has a reasonable gain, the noise
figure and thus signal to noise ratio is
determined largely by the noise figure of the
preamp. On HF, making a reasonably accurate
attenuator using power resistors can be easy. At
UHF, component, lead and wiring inductance can
make it a very difficult job -- but all is not lost!
Now for the really simple part. You need coax
cable between the radio and amplifier anyway (see
Figure 1). If you use coax with a loss of 2.2 dB,
you're done. On 440 MHz, it takes just 16 feet of
Belden 8259 RG-58 coax to get the loss --
hopefully emphasizing my earlier point! If you
select a different cable, make sure you have the
cable attenuation specs available. The extra coax
can be neatly coiled out of the way, or better
yet, move the amplifier closer to the antenna to
reduce the coax length and attenuation between
the amplifier ad antenna. Note that this all
assumes that the amplifier input is a good match
to 50 ohms; if not, the coax loss will be higher.
If you have a wattmeter, it will be a good idea
to confirm all the power levels when you're done
-- and life being what it is -- plan to do a little trimming.
Thanks Doctor! Do you have a question or a
problem? Send your questions via
<http://groups.yahoo.com/group/AlleghenyValleyRadio/post?postID=zpPOqQ_tDRUgz8PtrOLu7ReN8SebO3NBKYSpUQMK52ADP9llBYDxeNcBsVrABCPPnXowtP8cnIt4>e-mail
or to "The Doctor," ARRL, 225 Main St, Newington,
CT 06111 (no phone calls, please). Look for "The
Doctor Is IN" every month in
<http://www.arrl.org/qst>QST , the official journal of the ARRL.
+ International Spotlight: ARRL Represented at
Europe's Largest Amateur Radio Convention
Billed as Europe's biggest Amateur Radio
exhibition, HAM RADIO 2010 was held in
Friedrichshafen, Germany, June 25-27, 2010. The
event is held annually in the Lake Constance
region. Each year, a contingent from the ARRL has
attended HAM RADIO in Friedrichshafen, greeting
our non-US members and networking with other
national radio societies. ARRL also supports DXCC
card checking at its booth -- a very popular
activity among the international community who
travels to this large show. The ARRL, as
International Secretariat for the International
Amateur Radio Union, also hosted a meeting area
for IARU officials and friends at the convention.
Last year's HAM RADIO had 17,400 visitors and
nearly 200 exhibitors from 30 nations. Pictures
from this year's event have been posted to ARRL's
Facebook page. Read more
<http://www.arrl.org/news/arrl-represented-at-europe-s-largest-amateur-radio-convention>here<http://www.arrl.org/nladclick.php?n=al&t=i&i=2010-07-01&p=2>.
Amateur Radio in Space: IARU International
Amateur Radio Satellite Forum Scheduled in Conjunction with AMSAT-UK Meeting
The IARU International Amateur Radio Satellite
Forum will be held in conjunction with the
<http://www.uk.amsat.org/content/view/32/42/>AMSAT-UK
Colloquium in Guildford, England on the weekend
of July 31-August 1. The forum -- chaired by IARU
Amateur Satellite Advisor Hans van de
Groenendaal, ZS6AKV -- will take place on Sunday
morning, August 1. A report back on the
activities of the IARU Satellite Adviser and his
Advisory Panel will be one of many items on the
meeting's agenda. There will also be a brief
presentation covering the ITU notification
requirements for satellites operating in the
Amateur Service and the requirement to disable
transmissions should the signals interfere with
other users of the radio spectrum. The forum is
open to all delegates at the Colloquium. For more
information, including hotel and registration
information, please see the AMSAT-UK
<http://www.uk.amsat.org/content/view/32/42/>Web site.
+ Solar Update
The Sun, as seen on Thursday, July 1, 2010 from
<http://sohowww.nascom.nasa.gov/data/realtime/realtime-update.html>NASA's
SOHO Extreme Ultraviolet Imaging Telescope. This
<http://soi.stanford.edu/>MDI (Michelson Doppler
Imager) image was taken in the continuum near the
Ni I 6768 Angstrom line. The most prominent
features are the sunspots. This is very much how
the Sun looks in the visible range of the spectrum.
Tad "<http://www.bartleby.com/145/ww290.html>Like
a vast river, stretching in the Sun" Cook, K7RA,
reports: The conditions were not great for ARRL
Field Day last weekend, but some nice sporadic-E
openings on 6 and 10 meters livened things up.
Geomagnetic conditions were quite active over the
past week, which increased absorption, with the
higher latitudes more affected than
mid-latitudes. The average daily sunspot numbers
over the past three weeks were 26.9, 16.1 and
11.7, so quiet conditions continue with very
little solar activity. Look for more information
on the ARRL Web site on Friday, July 2. For more
information concerning radio propagation, visit
the
<http://www.arrl.org/propagation-of-rf-signals>ARRL
Technical Information Service Propagation page.
This week's "Tad Cookism" brought to you by
William Wordsworth's
<http://www.bartleby.com/145/ww290.html>Growth of
a Poet's Mind: Book Fourth, Summer Vacation.
+ ARRL to Close in Observance of Fourth of July
ARRL Headquarters will be closed in observance of
Independence Day on Monday, July 5. There will be
no W1AW bulletin or code practice transmissions
that day. League Headquarters will reopen
Tuesday, July 6 at 8 AM Eastern Daylight Time. We
wish everyone a safe and festive holiday weekend.
This Week on the Radio
ARRL member Pete Friedrichs, AC7ZL, is a
published author who is presently working on a
new book titles Marvelous Magnetic Machines. Pete
is a dedicated homebrewer who takes radio to its
roots -- even building his own vacuum tubes. In
this video, he features homebrew electric motor
projects from his new book. According to Pete,
they were built from household scrap and garage
sale pickings. Even the music behind the video is
homebrew -- it's an original instrumental
performed by a three-piece band Pete belonged to
back in the 1980s. Click
<http://www.youtube.com/watch?v=BNp-ICvvM1o>here to watch the video.
This week, there is another running of the NCCC
Sprint Ladder on July 2. The DL-DX RTTY Contest
and the Venezuelan Independence Day Contest are
July 3-4. The Michigan QRP July 4th CW Sprint is
July 4-5. Next week, the FISTS Summer Sprint is
July 10 and the IARU HF World Championship is
July 10-11. All dates, unless otherwise stated,
are UTC. See the
<http://www.arrl.org/contests>ARRL Contest Branch
page, the
<http://www.arrl.org/The-ARRL-Contest-Update>ARRL
Contest Update and the
<http://www.hornucopia.com/contestcal/index.html>WA7BNM
Contest Calendar for more info. Looking for a
Special Event station? Be sure to check out the
<http://www.arrl.org/special-events>ARRL Special Event Station Web page.
ARRL Continuing Education Course Registration
Caption goes here
Registration remains open through Sunday, July
25, 2010, for this
<http://www.arrl.org/online-course-registration>online
course session beginning on Friday, August 6,
2010: Amateur Radio Emergency Communications
Level 1. To learn more, visit the
<http://www.arrl.org/online-courses>CEP Course
Listing page or contact the
<mailto:cep at arrl.org>Continuing Education Program
Coordinator<http://www.arrl.org/nladclick.php?n=al&i=2010-07-01&t=r&p=0>.
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