[ETS/PARC List] ARRL'S TECHNICAL INFORMATION SERVICE PROVIDES MEMBERS WITH ANSWERS

[Drew Moore]

-------- Original Message --------
Subject: 	ARRL'S TECHNICAL INFORMATION SERVICE PROVIDES MEMBERS WITH 
ANSWERS
Date: 	Fri, 01 May 2009 19:43:53 -0400
From: 	Drew Moore <drumor at optonline.net>
To: 	undisclosed-recipients: ;



==> ARRL'S TECHNICAL INFORMATION SERVICE PROVIDES MEMBERS WITH ANSWERS 

Have you ever had a technical question that you weren't able to figure
out? Even after checking with publications such as The ARRL Handbook or
the ARRL Antenna Book, you're still stumped. Have you exhausted every
resource you can think of, including your Section's Technical
Coordinator (TC) <http://www.arrl.org/FandES/field/org/tc.html>? Just
when you think you're at the end of your rope, you remember the ARRL
Technical Information Service <http://www.arrl.org/tis/>.

The TIS is staffed by members of the ARRL Lab and is here to provide
technical assistance at no cost to ARRL members. Many members seem to be
using the service: In a six week period (October 20-November 30, 2008),
ARRL Lab staff fielded almost 1300 requests for information from the
TIS. These ranged from questions on how to choose the best radio,
propagation and BPL to questions concerning antennas, feed lines and
towers.

ARRL TCs and Technical Specialists (TS)
<http://www.arrl.org/FandES/field/org/ts.html> in the field and at ARRL
Headquarters can answer your questions on topics ranging from A (ampere)
to Z (impedance) -- and just about anything in between. Our technical
staff will help you over the phone, refer you to a volunteer ARRL TS in
your area or send you the needed information from a growing collection
of information packages. For really difficult questions, an ARRL Lab
Engineer will research the League's technical library and send you an
answer by postal or electronic mail.

ARRL Lab Engineer Mike Gruber, W1MG, remembers a question that a member
sent in recently via e-mail: "I have a 250 foot run of Buryflex 213 from
the shack to the switchbox at the top of the tower. I know that results
in significant loss at, say, 14 and 18 MHz (I seldom work 10 or 15 and
the tower antennas are only for HF), but here is the question: Is it
ENOUGH of a loss (for the receiver) to warrant running hardline (it
would be free) between the shack and tower switchbox with a tail of
about 10 feet of 213 inside the shack, and another tail of about 10 feet
at the tower end, running from the switchbox to the TA-33, considering
the insertion loss of two additional connectors (to connect the hardline
to the 213 on each end) and the impedance difference of the hardline
compared with the 213?"

Gruber answered the ham, providing a chart he developed, showing "some
losses shown for 250 feet of RG-213 vs half-inch hardline. I selected
50, 100 and 150 ohm resistive loads for this analysis. Any rate, if you
consider the case with the highest loss -- 29 MHz with a 150 ohm load --
will only improve by 3.9 - 1.544 = 2.4 dB. If you consider that a
typical S-unit is 6 dB, the most dramatic improvement in the example
cases I selected is still less than half of an S-unit. It's not a
homerun by any stretch of the imagination. Of course, that extra 2.311
dB may be significant in some cases. If you ran 1500 W, you would only
have 881 W at the antenna feed point. The rest would be lost in the feed
line."

ARRL Senior Lab Engineer Zack Lau, W1VT, recalls an interesting question
he received from a member: "How can I make a simple circularly polarized
antenna out of linear elements?" Lau referred him to an article he
wrote, "A Simple 10-Meter Satellite Turnstile Antenna," that appeared in
the November/December 2001 issue of QEX.

The TIS, as one of the many services it offers, maintains a database of
more than 2000 suppliers that provide goods and services of interest to
radio amateurs <http://www.arrl.org/tis/tisfind.html>. These include
manufacturers, dealers, publications, clubs and museums, just to name a
few. The TIS also keeps what they call an "expanding list" of technical
pages that include articles from QST, QEX and The ARRL Handbook, as well
as original articles on a variety of subjects including theory,
tutorials and projects <http://www.arrl.org/tis/tismenu.html>. Many
pages also contain additional sources for materials and information and
Web links of particular interest.

If you need a copy of the QST Product Review from May 1985 that featured
the ICOM IC-271A 2 meter multimode transceiver, look no further. The TIS
also keeps a list of every QST Product Review published since 1970
<http://www.arrl.org/tis/info/prodrev.html>. ARRL members can also
download any QST Product review published after 1980
<http://www.arrl.org/members-only/prodrev/bymfg.html>. If you need a
quick summary of any HF transceiver featured in a QST Product Review,
you can also find it on the TIS Web site.

The TIS also maintains the ARRL Periodicals Archive and Search
<http://www.arrl.org/members-only/qqnsearch.html>. This feature provides
ARRL members with PDF copies of all QST articles from December 1915
through December 2005, enabling members to view and print their favorite
article, project and more. The ARRL Periodicals Archive and Search lists
every article for QST from 1915 to the present, QEX from 1981 to the
present, Ham Radio Magazine from 1968 to 1990 and NCJ from 1973 to the
present (please note that beginning in 1998, each issue of QEX covers
two months).

"Having access to every issue of QST through 2005 is absolutely
incredible!" said ARRL Lab Manager Ed Hare, W1RFI. "The best of the best
of QST from every era is now at the fingertips of every ARRL member with
a keyboard and an Internet connection. Members can research articles on
any subject that interests them, or just browse the past issues. This
valuable content will help radio amateurs who use QST as a technical
resource -- for projects, equipment 'hints and kinks' -- and for other
research contributing to the advancement of the radio art."

For those needing a higher quality reprint, a reprint from QEX or NCJ,
or for hams who are not members of the ARRL, the TIS also provides
photocopies of articles for a nominal fee
<http://www.arrl.org/members-only/artcopies.html>. You can reach the TIS
via e-mail <mailto:tis at arrl.org> or by phone at 860-594-0214.

The TIS is just one of the many benefits available to ARRL members. To
learn about all the benefits of ARRL membership, including QST, e-mail
forwarding service, the outgoing QSL service and more, please visit the
ARRL Membership Web page <http://www.arrl.org/join>.