QRZ! Ham Radio 3/QRZ Ham Radio Callsign Database - Volume 3.iso/digests/infoham/931437.txt

Internet Message Format | 1994-06-04 | 33KB

Date: Wed,  8 Dec 93 16:14:12 PST
From: Info-Hams Mailing List and Newsgroup <[e-mail]>
Errors-To: [e-mail]
Reply-To: [e-mail]
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Subject: Info-Hams Digest V93 #1437
To: Info-Hams


Info-Hams Digest            Wed,  8 Dec 93       Volume 93 : Issue 1437

Today's Topics:
                    ARRL's callsign admin position
                       codes in rptr directory
                        Mods -> Kenwood TS450
   rec.radio.amateur.misc Frequently Asked Questions (Part 1 of 3)

Send Replies or notes for publication to: <[e-mail]>
Send subscription requests to: <[e-mail]>
Problems you can't solve otherwise to [e-mail].

Archives of past issues of the Info-Hams Digest are available
(by FTP only) from UCSD.Edu in directory "mailarchives/info-hams".

We trust that readers are intelligent enough to realize that all text
herein consists of personal comments and does not represent the official
policies or positions of any party.  Your mileage may vary.  So there.
----------------------------------------------------------------------

Date: 6 Dec 1993 12:59:32 GMT
From: agate!howland.reston.ans.net!gatech!usenet.ufl.edu!mailer.acns.fsu.edu!freenet2.scri.fsu.edu![e-mail]
Subject: ARRL's callsign admin position
To: [e-mail]

Re: Call Sign Administration Hassle

Nice set of comments, Brian. You are right on target.

ARRL needs to proceed slowly and responsibly on this one. I thought
they had their "politically smart" hat on these days, but after this
recent nonesense, I'm not so sure. It would be a tragedy for the FCC
to get cold feet and back off because of arguments in the amateur
radio ranks. Its been 15 years since the last call sign-request
program was operational. That is a very long time. Its not the time
to rock the boat as the FCC edges back into these waters, I feel.

73,

Michael Christie, K7RLS
Crawfordville, Florida

------------------------------

Date: 8 Dec 93 20:57:36 GMT
From: [e-mail]
Subject: codes in rptr directory
To: [e-mail]

Just purchased ARRL repeater directory, and I'm seeing some abbreviations
in the notes listings for which I don't find explanation.  Could someone
translate, please?  (So far, I've been able to figure out the rest.)

p. 122, Florida  New Port Richey      notes:   twa
t = tone access
w = ?
a = autopatch ?
twa = arrival airline required to access?

same page, Sarasota 3rd listing       notes:   ottabier
o = open
tt = touch-tone
a = autopatch
bi = misprinted bl for bi-lingual?
e = emergency power
r = rat on treadmill for power?
bier = ?   Buy one of these for the owner of the repeater, to support use?

Need to know before Dec 20, when I get on the plane.    Thanks!

Paul Marsh    N0ZAU    Omaha
[e-mail]

------------------------------

Date: Wed, 8 Dec 1993 12:47:18 GMT
From: iris.mbvlab.wpafb.af.mil!blackbird.afit.af.mil!blackbird![e-mail]
Subject: Mods -> Kenwood TS450
To: [e-mail]

In article <[e-mail]> [e-mail] (Rick H.) writes:


       Hi, My friend asked me to post this, as that he is looking for ANY
   modifications for the Kenwood TS-450. He wants it to be able to TX/RX
   11 Meters. But mods for this radio are desired...

       Email Please                    [e-mail]
           [e-mail]

Gee...I always wanted a nuclear-strength flamewar for Christmas...:-)

(I've adjusted the Distribution:; no sense polluting the rest of the world)

73,

Jeff   NH6ZW/N8   AFA1HE


--
Jeff Miller,  NH6ZW/N8,  AFA1HE (ex WD6CQV, AFA8JM, AFA1DO)
AFIT School of Engineering, Wright-Patterson AFB, OH.  Help eliminate FOD.
Welcome to Ohio:  Our state flower is the orange highway construction barrel.
55: It's not a good idea; it's just the law.  E-mail me about the NMA.

------------------------------

Date: Tue, 7 Dec 1993 02:43:04 GMT
From: amd!amdahl!thunder![e-mail]
Subject: rec.radio.amateur.misc Frequently Asked Questions (Part 1 of 3)
To: [e-mail]

Posted-By: auto-faq 3.1.1.4
Archive-name: radio/ham-radio/faq/part1
Revision: 3.0 1993/11/07 18:38:38

Rec.radio.amateur.misc Frequently Asked Questions
Part 1 - Introduction to the FAQ and Amateur Radio
------------------------------------------------------------------------------

This is a regular posting of frequently-asked questions (FAQ) about Amateur
Radio, also known as Ham Radio.  It is intended to summarize some common
questions on the rec.radio.amateur.misc newsgroup and Info-Hams mail list
as well as to help beginners get started.

Please provide a copy of the FAQ to any new or soon-to-be Hams you know.

Regular FAQ postings can help save network bandwidth and maintain a good
signal-to-noise ratio in the newsgroup.  However, they can't do it alone - you,
the reader, have to use them.  If you are a new user, please print and review
the FAQ articles and look at the instructions in the news.announce.newusers
newsgroup before posting any articles.  If you are an experienced user, please
help by refraining from answering frequently-asked questions on the newsgroup
if they are already answered by the FAQ articles.  Instead, send e-mail to the
user who asked the question.  (It will be helpful if you include the part of
the FAQ that answers their question, but not the whole thing.)

The FAQ cannot always prevent people from posting repetitive questions.  But
even if hundreds of questions get posted, it saves you from having to answer
them hundreds of times.  Also, a friendly pointer to the FAQ in your first
answer can help that person refer to the FAQ in the future.  That is when we
can begin to get a real savings of network bandwidth.

To reduce the size of each article, the FAQ information is posted in 3 parts:
Part 1 - Introduction to the FAQ and Amateur Radio
Part 2 - Amateur Radio Organizations, Services, and Information Sources
Part 3 - Amateur Radio Advanced and Technical Questions


Table of Contents
-----------------
Dates indicate last modification.

Part 1 - Introduction to the FAQ and Amateur Radio
**  Table of Contents (6/93)
**  Introduction to the FAQ (11/92)
    * How to Contribute to the FAQ Articles (6/93)
    * Acknowledgements (6/93)
    * Notes on "Netiquette" (1/93)
**  What is Amateur Radio? (11/92)
**  Who can become a ham? (6/93)
**  Where can I locate information and books on Amateur Radio? (9/93)
**  How much does it cost? (9/92)
**  Where can I take the tests? (9/93)
**  What are the tests like? (6/93)
**  What can I do with a ham radio license? (5/92)
**  What can't I do with an Amateur Radio license? (pre-4/92)
**  I'm interested, who will help me? (11/92)
**  Should I build my own equipment or antenna? (11/92)

Part 2 - Amateur Radio Organizations, Services, and Information Sources
**  Where can I find Ham Radio information with a computer? (11/92)
    * The rec.radio.* newsgroups (6/93)
    * The ARRL e-mail server (1/93)
    * The KA6ETB e-mail "HAM-server" (new 9/93)
    * The Internet File Transfer Protocol (FTP) (9/93)
    * Access to FTP archives via electronic mail (1/93)
    * The Ham-Radio mail list: rec.radio.amateur.misc by mail (9/93)
    * Telephone BBS's with Ham-related information (9/93)
    * Callsign servers and geographical name servers (11/92)
    * FTP access to FCC Part 97 and FCC Amateur Radio question pools (9/93)
    * Lists of radio modifications and extensions (11/92)
**  Can I send ARRL or W5YI electronic mail? (11/92)
**  "Why doesn't the ARRL do...?" (11/92)
**  What magazines are available for Ham Radio? (pre-4/92)
**  How do I use the incoming and outgoing QSL bureau? (11/92)
**  Are there any news groups for CAP? (11/92)
**  What's the name of the QRP club that issues QRP numbers? (9/93)
**  How do I become a 10-10 member? (9/93)
**  How do I join MARS? (9/93)
**  How do I join RACES? (pre-4/92)
**  What organizations are available to help handicapped hams? (pre-4/92)
**  I am looking for a specific ham, can anyone help me find him? (6/93)
**  Can I post my neat new ham related program on rec.radio.amateur.misc?
    (pre-4/92)
**  Where can I get ham radio software for my computer? (9/93)
**  Are there Dialup News services or BBSs for Amateur Radio? (4/92)
**  Where can I find VE sessions in my local area? (9/93)
**  Why isn't XXX available electronically? (4/92)

Part 3 - Amateur Radio Advanced and Technical Questions
**  What are the different US amateur classes and what can each of them do?
    (pre-4/92)
**  What is the best way to learn Morse Code? (10/92)
**  What is the standard for measuring Morse code speed? (pre-4/92)
**  What is the standard phonetic alphabet? (new 9/93)
**  I'm confused. What do all those abbreviations mean??? (6/93)
**  What do all those "tones" mean? (pre-4/92)
**  Where can I learn more about Amateur Radio if I live outside the US?
    (9/93)
**  How can I get a "reciprocal license" if I am a licensed ham from another
    country or if I am a FCC licensed ham who wants to operate in another
    country (on vacation)? (9/93)
**  My apartment or housing complex does not allow outdoor antennas, now what
    do I do? (9/93)
**  I got TVI...HELP!!! (9/93)
**  Did you know that you can get college credit for being a ham? (pre-4/92)
**  On what frequencies do JPL and GSFC retransmit the shuttle audio?
    (10/92)
**  Can I take my HT on an airplane and operate it if I get the permission
    of the captain? (4/92)
**  How do I modify my current Amateur license? (9/93)
**  I'm confused about XXX, should I ask the FCC? (9/93)
**  Is there any information on antique radios? (pre-4/92)
**  Where can I buy vacuum tubes? (9/93)
**  What do I need to get started in packet radio? (9/93)
**  What do I need to get started in satellite communications? (9/93)
**  What is available to get started in ATV, SSTV and WEFAX? (9/93)
**  What are these contests I sometimes hear, and how do I participate? (9/93)


--Rec.radio.amateur.misc Frequently-asked Questions------------------Part 1--

**  Introduction to the FAQ

    * How to Contribute to the FAQ Articles

 We accept suggestions from the Amateur Radio community.  Please
 consider that all new contributions need to be SHORT and concise
 in order to be included.  If a contribution is too long, the FAQ
 editors can help you find a more appropriate FTP archive or mail
 server for your article.

 We always accept corrections.  Please allow some time (often not
 the next issue of the FAQ) because the FAQ maintainers do this as
 volunteers so each must give higher priority to their employers.

 Send correspondence to  [e-mail]  so that it will
 reach all the FAQ coordinators: (listed in alphabetical order)

 Ed Hare         KA1CV  [e-mail]          (Newington, CT, USA)
 Jack GF Hill    W4PPT  [e-mail](Brentwood, TN, USA)
 Ian Kluft       KD6EUI [e-mail]   (Santa Clara, CA, USA)
 Michael Larish  KD6CTZ [e-mail] (Chico, CA, USA)
 Paul Schleck    KD3FU  [e-mail]    (Omaha, NE, USA)
 Chris Swartout  N6WCP  [e-mail]    (San Jose, CA, USA)
 Steve Watt      KD6GGD [e-mail]  (San Jose, CA, USA)
 Rosalie White   WA1STO [e-mail]         (Newington, CT, USA)
 Derek Wills     AA5BT  [e-mail] (Austin, TX, USA)

    * Acknowledgements

 All questions listed as modified "pre-4/92" are entirely Diana
 Carlson KC1SP's work or her editing of a contributor's work.  Diana
 established this FAQ and credit is due to her for founding this
 project.

 Thanks to Devon Bowen KA2NRC for accepting this FAQ in e-mail every
 month to keep the FTP archive at ftp.cs.buffalo.edu up-to-date.

    * Notes on "Netiquette"

 The rec.radio.amateur.misc newsgroup and Info-Hams mail list have a
 large daily volume of traffic.  They can operate more efficiently if
 the following netiquette guidelines are followed.  Please take them
 seriously.
 * If you are new to UseNet, the introductory articles in
   news.announce.newusers are required reading.  Go to that newsgroup
   now.  Definitely, read the instructions there before posting
   anything.  Other rec.radio.amateur.* readers will appreciate it!
 * Pick the right newsgroup.  Use only the most specific newsgroup
   for your subject.  For example, a question about a homebrew antenna
   only needs to be posted to rec.radio.amateur.antenna.  Also, don't
   post to rec.radio.amateur.misc when the subject can go in another
   rec.radio.amateur.* newsgroup.  So, when there is a more specific
   newsgroup, that's the one you want.
 * When posting a followup article, ALWAYS try to minimize the number
   of lines of quoted material from the original article.
 * As a general rule when you try to determine whether to reply to
   someone by e-mail or with a followup article, remember to "praise in
   public, criticize in private."  It's OK to disagree technically but
   be careful not to attack the person with whom you disagree.  Also,
   be careful with your use of the word "you" when posting a follow-up
   article.  Many unnecessary flame wars have started that way.
 * Use a descriptive subject.  For example, a message subject of "Ham
   Radio" tells the reader NOTHING about the contents of your article
   since the whole newsgroup is about Ham Radio.  Other examples of
   subjects which are so broad that they become useless could include,
   "Help," "A Question," "Antennas," or "Frequencies."  Maybe "Books on
   Antennas?" or "Where can I find Repeater Frequencies?" would be
   better, for example.  Remember, in a busy newsgroup a lot of users
   decide which articles to read from the subject line alone.  If you
   post, don't deprive yourself of an audience!
 * Before answering a question, check if the FAQ adequately answers it
   or if someone else already answered it.  If you have more to add,
   make sure to reference either the FAQ or the related articles.
 * If a user posts a question which is directly answered by the FAQ,
   there is no need to post an answer - the information is already
   available on the newsgroup.  Instead, just send an e-mail message
   which politely explains where to find the FAQ.  They will probably
   appreciate it if you include the answer to their question.  (Don't
   send a "nastygram" - that would just discourage future participa-
   tion.)
 * Pay attention to the size of your audience - use the "Distribution:"
   header.  If you leave it blank, your message will go to every civ-
   ilized country in the world and occupy disk space in all news sys-
   tems in all those places.  If that's what you intend, that's fine
   but make sure your article is relevant outside your country.  (In
   particular, Hams should already know there is more to the world than
   just their own country.)
 * If you have an item for sale, please limit the distribution area so
   that, for example, an article about a radio for sale in New Jersey
   won't get to California or Europe.  If you wish, you may cross-post
   your for-sale article to rec.radio.swap.
 * Software sources should be posted to either alt.sources,
   comp.sources.misc, or comp.sources.* for a specific machine type.
   Software binaries should be posted to the appropriate subgroup of
   comp.binaries.

**  What is Amateur Radio?
 Amateur Radio is a non-commercial radio communication service whose
 primary aims are public service, technical training and experimenta-
 tion, and communication between private persons.  Amateur Radio opera-
 tors are commonly called hams.  Hams often communicate with each other
 recreationally but also provide communications for others at public
 events or in times of emergency or disaster.

**  Who can become a ham?
 The answer to this question differs in every country.

 The answer for the USA is listed below.  If your country has
 a newsgroup specifically for it (i.e. UK, Australia, Germany)
 the most accurate answers can be found there.  See Part 2 for
 the list of region-specific newsgroups.

 If that doesn't help, the American Radio Relay League (ARRL)
 may be able to help because they communicate with similar
 organizations in other countries, probably including yours.
 They can be reached by electronic mail or surface mail (see
 Part 2.)

 In the USA, anyone who is not a representative of a foreign
 government can be an Amateur Radio operator.  There are tests
 that you must pass to get a license, however the tests are not
 insurmountable.  On that general level, the requirements are
 probably similar in almost every country.

 For more information on becoming a Ham in the USA, the ARRL
 has a toll-free number where you can request information:
 1-800-32-NEW-HAM (don't worry about the number being one digit
 too long - the phone system ignores it.)  Other information
 can also be obtained from the ARRL e-mail information server in
 the file called PROSPECT.  Details on the server are in Part 2.

**  Where can I locate information and books on Amateur Radio?
 Your local Radio Shack sells some ham radios and Amateur Radio
 license books.  Books can also be obtained through the mail
 from ham radio organizations, such as ARRL in Newington, CT
 (203-666-1541) and W5YI in Dallas, TX (1-800-669-9594).  There
 may be one or two ham radio stores in the local area (ie,
 within 50 miles).  Try looking in the Yellow Pages under Radio
 Communications.

 For the Novice license, get a Novice License manual, plus 5-word-per-
 minute Morse code tapes, costing around $25.  For the Technician lic-
 ense, get a combined Novice and Technician License manual, and an FCC
 Rules manual, costing around $32.  The FCC Rules manual is a good idea
 for Novice also, but not necessary, since the Novice License manual
 contains all the FCC Rules that are required for the Novice License.

 The ARRL Education Activities Department has several programs to
 help amateurs (or prospective amateurs) to get started.  Ask for a
 "New prospect package" available free of charge, from ARRL HQ,
 Educational Activities Department, 225 Main St, Newington, CT 06111.

 Information on Ham Radio can also be obtained with your computer.
 Part 2 of this FAQ contains a significant amount of material on
 that subject.

**  How much does it cost?
 To take the tests for any class of amateur radio license, there is
 a small charge (around $5-$6 currently) to cover copying costs and
 running the testing sessions.  (Due to changes in 1993, Novice tests
 are under same procedures as the others.)  The cost of a radio is
 really dependent on what you want to do.  You can make your own radio
 and antenna for under $150.  You can buy a used single-band radio for
 $150-$300.  Or you can buy a new multi-band multi-mode radio with all
 the doodads for $300-$3000.  I'd suggest you learn more about ham
 radio, talk to local hams, find out what you want to do with ham
 radio first.

**  Where can I take the tests?
 The Novice tests Used to be given by any two qualified hams of General
 class license or above.  Now all the license tests are given by
 three qualified Volunteer Examiners (VEs) who volunteer their time.

 To locate an ARRL testing session in your area, you can contact
 ARRL at 203-666-1541 x282.

 See also the section "Where can I find VE sessions in my local area?"
 in Part 2 because more information is available via UseNet.

**  What are the tests like?
 First off, come prepared to VE sessions.  Bring:  TWO forms of ID,
 one of which has a picture on it; a calculator (if necessary); a pen
 and two pencils; the applicable examination fee (around $5-$6 for
 1993); the original AND a copy of your current Amateur Radio license
 (if you have one); the original AND a copy of any CSCEs for tests
 you've already passed (if you have any).

 Each of the written tests (Novice, Technician, General, Advanced,
 and Extra) are generally a multiple choice test of approximately one-
 tenth of the question pool.  For example, if the question pool is
 approximately 300 questions, then the test will be a 30-question
 test.  You need to get 75% correct to pass.  Note that they truncate
 to determine the correct number of questions.  That means for a 30
 question test, you need to get 22 right, which is actually only 73.3%.

 Once you've paid the small fee for Technician-Extra tests, it costs
 no extra to take another test, so I'd suggest you keep taking the
 next more advanced test until you fail.  If you pass the written
 but not the Morse code (or vice versa) for a specific class license,
 you have up to one year to take the other test before you would have
 to retake the written test again.  Note that some VEs will not allow
 you to take the written test unless you've first taken the Morse code
 test.

 The Morse code test is a receiving test only.  The test run 5 to 7
 minutes.  After the test, you are given a 10-question multiple-choice
 or fill-in-the-blank test.  Passing grade is 7 or more.  If you fail
 the 10-question test, the examiner team will examine your copy sheet
 to see if you have 1 minute of solid copy with no errors.  For 5 wpm,
 that's 25 characters, for 13 wpm, that's 65 characters, for 20 wpm,
 that's 100 characters.  If they can find 1 minute solid copy, you've
 still passed.

 Hints on Morse code tests:  Generally, it will be a standard QSO
 (conversation), and it MUST contain at least one of each of the
 following:
 26 letters A-Z, 10 numbers 0-9, comma (,), period (.), slant or
 slash (/), question mark (?), double dash prosign (BT), end of
 message prosign (AR), end of contact prosign (SK).
 The letters count as one character, all others count as two
 characters.  There are a couple other prosigns which are worth
 knowing, but will not be on the test, like "I'm done talking, next"
 is K, "I'm done talking, back to you" is KN, "Please wait" is AS.

**  What can I do with a ham radio license?
 There are so many things, it's a difficult question to answer, but
 here's some ideas:
 * Talk to people in foreign countries.
 * Talk to people (both local and far away) on your drive to work.
 * Help in emergencies by providing communications.
 * Provide communications in parades or walkathons.
 * Help other people become hams.
 * Hook your computer to your radio and communicate by computers.
 * Collect QSL cards (cards from other hams) from all over the
   United States and foreign countries and receive awards.
 * Participate in contests or Field Day events.
 * Provide radio services to your local Civil Defense organization
   thru ARES (Amateur Radio Emergency Service) or RACES (Radio Amateur
   Civil Emergency Service).
 * Aid members of the US military by joining MARS (Military Affiliate
   Radio System).
 * Participate in transmitter hunt games and maybe build your own
   direction-finding equipment.
 * Have someone to talk to on those sleepless nights at home.
 * Receive weather pictures via satellites.
 * Build radios, antennas, learn some electronics and radio theory.
 * Talk to astronauts in space, or use the moon to bounce signals
   back to people on the Earth.
 * Experiment with Amateur TV (ATV), Slow-Scan TV (SSTV), or send
   still-frame pictures by facsimile.
 * Experiment with amateur satellite communications.

**  What can't I do with an Amateur Radio license?
 The most important thing you can't do is transact business of any
 kind over ham radio.  Interference to other hams or services, as
 well as obscene, profane or indecent language is not tolerated and
 is illegal.  Music and broadcasting are not allowed on ham radio.
 Some personal conversations may not be appropriate to Amateur Radio.
 Do you really want the whole world to hear about Aunt Mabel's
 hemorrhoids?

**  I'm interested, who will help me?
 There are hams who are willing to become "Elmers" (mentors, helpers)
 in your local area.  Look around and ask local hams.  Search out local
 radio clubs.  As well, some people have volunteered to be an Elmer
 over the Usenet.  A list of UseNet Elmers and their e-mail addresses
 is posted to the newsgroup monthly.  If anyone wants to be an Elmer,
 send e-mail to
  [e-mail]

 There is also a lot to be said for exploring on your own.  Take a
 look around the FTP archives and e-mail servers listed in Part 2.
 There's so much out there on UseNet, you'll find plenty of things
 you're interested in.

**  Should I build my own equipment or antenna?
 [see also rec.radio.amateur.homebrew and rec.radio.amateur.antenna]
 "Homebrewing" is a fun and educational part of ham radio.  It is a
 thrill to build your own transmitter and put it on the air.  However,
 building your own receiver can be quite complicated; if you don't have
 electronics experience, you may want to buy a receiver instead.  Most
 homebrew transmitters are QRP (transmit very low power).  That's fine
 for an experienced ham with a very good antenna, but a Novice ham will
 just get frustrated.  Your first rig, therefore should NOT be a home-
 brew.

 Antennas can be much simpler projects than the transceiver, though
 some types are also quite involved.  Most hams build their own anten-
 nas for base station use and buy antennas for mobile (car) use.  Most
 beginner ham books describe how to build different types of antennas.
 Order of difficulty, from easiest to more difficult, for some common
 antennas are:  wire dipole, Zepp, Yagi, Quad, and Log-Periodic.  Books
 from many sources, including ARRL and several Hams, discuss antennas
 in depth.

 When building or even understanding antennas, it is good to know the
 relationship between the antenna element length and the frequency or
 wavelength it is designed for.  An antenna performs best at multiples
 of 1/4 of that wavelength, though 5/8 wave also has beneficial qualit-
 ies.  The wavelength is related to the frequency with the following
 formula:

 wavelength (in meters) = 300 / frequency (in megahertz)

 You do not need a huge antenna or tower like ones you may see around
 your neighborhood.  Large beam antennas and 40-foot towers are very
 expensive.  As a beginner, a simple dipole antenna is perfectly
 adequate.  As you gain experience (and money :-), you may want to
 invest in something bigger.

 If you can afford new rigs and antennas, there are many mail order
 stores that advertise in ham radio magazines.  If you want to buy a
 used rig, the best place is at a "hamfest" (ham flea market).  You
 should take along an experienced ham, since some of the used equipment
 may be inoperative, overpriced or poor quality.  You can also answer
 ads in ham magazines or posted at ham radio stores, although often, by
 the time you call, the equipment has already been sold.

------------------------------

Date: Wed, 8 Dec 93 18:53:00 GMT
From: library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!cs.utexas.edu!swrinde!sgiblab!uhog.mit.edu!xn.ll.mit.edu!ll.mit.edu![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <[e-mail]>
Subject : Re: hypochondriac scared of cancer!


In article <[e-mail]>, [e-mail] (Bill Chiarchiaro) writes:
|>
|> ...stuff deleted...
|>
|>  Power Flux = Power / Area = 0.2570 W/m^2
|>       = 2.570 mW/cm^2
|> ...stuff deleted...
|>
|>   Note also that to convert from W/m^2 to mW/cm^2 you need to multiply
|> by 10.
|>


  Damn, I hit that "send" button too fast.  The line about power flux
should have read:

  Power Flux = Power / Area = 0.2570 W/m^2
       = 2.570x10^-2 mW/cm^2

  The line about the conversion factor should have read:

   Note also that to convert from W/m^2 to mW/cm^2 you need to _divide_
by 10.

  Sorry for the QRM.


73

Bill Chiarchiaro  N1CPK
[e-mail]

------------------------------

Date: Wed, 8 Dec 93 18:42:05 GMT
From: library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!cs.utexas.edu!swrinde!sgiblab!uhog.mit.edu!xn.ll.mit.edu!ll.mit.edu![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <[e-mail]>
Subject : Re: hypochondriac scared of cancer!


In article <[e-mail]>, [e-mail] (Gary Coffman) writes:
|>
|> ...stuff deleted...
|>
|> Ok, I made a couple of simplifying assumptions, and I cheated the
|> numbers a bit to make it easier to calculate, and then I screwed up. :-(
|>
|> First I assumed an industry standard Class A transmitter power of 3 kW.
|> It turns out that's correct for this station. I ignored the 5.44 db gain
|> antenna used to bring the main lobe signal up to 10.5 kW ERP. Since our
|> poster is located below the main lobe, this assumption makes the calculation
|> give a higher value for field strength at his window than actually exists,
|> and it makes the calculation much easier. Now I cheated by assuming that
|> the station was on 2 meters instead of 104.1 MHz. That made a halfwave 1
|> meter. Then I screwed up by assuming field strength falls off with the
|> inverse *square* of distance, it doesn't, power does. Field strength
|> falls off linearly with distance. Arrrgh!
|>
|> Now let's go through it with more accurate numbers. A halfwave at 104.1
|> is 150/104.1 or 1.44m. Now assuming a free space impedance of 377 ohms
|> the field strength across 1.44 meters is sqrt(3000*377) or 1063.48 volts per
|> 1.44m at 1.44m. Now let's normalize the voltage across 1m, 1063.48/1.44=738.53
|> volts/meter at a distance of 1.44m. Now 100 feet is 30.46 meters, so the
|> field strength decreases by 30.46/1.44=21.15 times. So the volts per meter
|> at the window is 738.53/21.15=34.92 volts per meter. I missed this by a
|> mile before. Note I'm not bothering with slant range from the top of the
|> tower, I'm just taking his 100 feet number for the distance.
|>
|> Note that the *tower* is 70 feet tall according to our poster, but
|> that's not the length of the *antenna*. I'm assuming a single bay
|> for simplicity of calculation. That's a halfwave dipole. Now the field
|> strength will be maximum across a sphere with a diameter of a halfwave
|> that just encompasses the element because there's a 180 degree phase
|> shift across a halfwave and that gives maximum voltage. That also happened
|> to be 1 meter in my simplified calculation, but turned into 1.44 meters
|> in the more accurate calculation. Since field strength falls off with
|> the inverse of the distance, and since we know the voltage at 1.44 meters,
|> it's simple to find the voltage at 30.46 meters. Now the power density is
|> P=E^2/R. Since R for free space is 377 ohms, we have 34.92^2/377=3.23 W/m^2.
|> Now divide that by 100,000 to get 0.0323 milliwatts/cm^2. I slipped a decimal
|> there before when calculating a power ratio directly. The power density is
|> well below the OSHA and ANSI limits.
|>


  Something's still wrong here.  The claim that the field strength
half a wavelength from the transmitting antenna is equal to the square
root of the product of the transmitted power and the impedance of free
space looks like a rule of thumb with which I'm not familiar.  In any
event, I claim that the resulting field strength figure at 100 feet is
off by a factor of 3.55 (I don't know if this is close enough to pi to
be suspicious).

  I calculate the field strength as follows (making the same isotropic
antenna assumption as did Gary):

 Radiated Power  = 3,000 watts

 Surface Area of
  100-foot-radius
  sphere centered
  on antenna  = 125,664 ft^2
    =  11,675 m^2

 Power Flux = Power / Area = 0.2570 W/m^2
      = 2.570 mW/cm^2

 Electric Field Strength   = sqrt(Power Flux * Free-Space Impdnc)
      = sqrt(0.2570 W/m^2 * 377 ohms)
      = 9.84 V/m rms

  Note also that to convert from W/m^2 to mW/cm^2 you need to multiply
by 10.


73

Bill Chiarchiaro  N1CPK
[e-mail]

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End of Info-Hams Digest V93 #1437
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