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1994-06-04
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29KB
Date: Thu, 16 Dec 93 01:58:51 PST
From: Info-Hams Mailing List and Newsgroup <info-hams@ucsd.edu>
Errors-To: Info-Hams-Errors@UCSD.Edu
Reply-To: Info-Hams@UCSD.Edu
Precedence: Bulk
Subject: Info-Hams Digest V93 #1468
To: Info-Hams
Info-Hams Digest Thu, 16 Dec 93 Volume 93 : Issue 1468
Today's Topics:
* SpaceNews 13-Dec-93 *
Baycom -> Amiga
Bravo, Bravo +, etc. pager options and programming ?
HELP!!ANYBODY WORK N8PPZ?
How to find the answers to frequently-asked questions about Ham Radio
Need Jan '78 Ham Radio magazine
TVI weirdness
Send Replies or notes for publication to: <Info-Hams@UCSD.Edu>
Send subscription requests to: <Info-Hams-REQUEST@UCSD.Edu>
Problems you can't solve otherwise to brian@ucsd.edu.
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: 10 Dec 93 17:32:16 GMT
From: news-mail-gateway@ucsd.edu
Subject: * SpaceNews 13-Dec-93 *
To: info-hams@ucsd.edu
SB NEWS @ AMSAT $SPC1213
* SpaceNews 13-Dec-93 *
BID: $SPC1213
=========
SpaceNews
=========
MONDAY DECEMBER 13, 1993
SpaceNews originates at KD2BD in Wall Township, New Jersey, USA. It is
published every week and is made available for unlimited distribution.
* MIR NEWS *
============
Jean-Claude, FB1RCI, of Marseille, France has provided a graphical view
depicting the altitude of the Russian space station Mir over the past year
based on the mean motion of the spacecraft:
Rev per day
15.53 I\_
I \_
15.55 I \_
I \__ _
_ I \__ _ __ I\ I
I \_ I \___ I \_ I \___ I \ I
15.60 _ _ I \_ I \__I \_I \____I \I
\_ I \_ I \/
\_ I \I
\_I
15.65
/\______________________________/\_________________________________/\__
1992 1993 1994
(I = Boost to higher orbit)
* AMSAT-OSCAR-13 NEWS *
=======================
AO-13 is now experiencing the longest eclipses it will ever experience,
indeed the longest that ANY amateur satellite has received! The period
affected is Dec 08 - 24. Most eclipses exceed 2 hours, with the longest
136 minutes on Dec 15th.
In addition, the Sun angle is -30 degrees and worsening, giving only 86%
illumination now, less later. The mode-B transponder is only just
sustainable, and is on for the minimum sensible time, MA 180-250 with a
break from 220-230 for mode-S exclusive.
There is no guarantee that even this is enough safety margin, and further
curtailments may be necessary, including a slight reorienation to collect
more sunlight.
The Whole Orbit Data collection in the K-block is presently monitoring
battery voltage. The safety threshold is 12.6 volts, when the on-board
computer will closedown the transponder if necessary. Bytes 64-191 are
voltage at 8 MA intervals, and convert as V = (N-10)*0.0668 volts.
Please be sensitive about your uplink power. Remember, optimum conditions
occur at only 30,000 km range now. Compared with apogee that's a 6 db round
trip improvement, so you can cut your power by 1/4 and be no worse off.
L QST *** AO-13 TRANSPONDER SCHEDULE *** 1993 Dec 08-Jan 31
Mode-B : MA 250 to MA 256 ! OFF Dec 08 - 24 | Eclipses, max
Mode-B : MA 0 to MA 180 ! OFF | duration 136
Mode-B : MA 180 to MA 220 ! minutes.
Mode-S : MA 220 to MA 230 !<- S transponder; B trsp. is OFF
Mode-BS : MA 230 to MA 250 ! Alon/Alat 240/-5
Omnis : MA 250 to MA 150 ! Move to attitude 180/0, Jan 31
Long eclipses and poor Sun angle now need maximum OFF time.
[Info via James, G3RUH @ GB7DDX.#22.GBR.EU]
* ITAMSAT-OSCAR-16 NEWS *
=========================
ITAMSAT-OSCAR-26 suffered a software crash at approximately 11:30 UTC
on 08-Dec-93 during a pass over Europe. The crash left the transmitter
on with no MBL or telemetry. The satellite was successfully recovered
on 09-Dec-93 through a joint effort by Alberto Zagni I2KBD and the Eyesat
ground station in the United States. IO-26 was reset to its safe mode
(MBL with transmitter off) at about 05:40 UTC.
Alberto, I2KBD, on the first evening pass over Europe was able to switch
the transmitter on again, and began some memory dumps in order to gain
more information about the software crash. The TX was switched on at
19:00 UTC, and is now sending MBL telemetry.
The ITAMSAT Command Team will probably delay the recommissioning of the BBS
on IO-26 to allow a better understanding of the orbital parameters, in order
to be able to raise the power when the BBS will be turned on again. Look
for any bulletin in the downlink for upcoming WODs.
The ITAMSAT Command Team would like to thank the Eyesat ground station,
Jeff Ward G0/K8KA and Harold Price NK6K for their help.
ITAMSAT Command Team can be reached via Internet as i2kbd@amsat.org
or ik2ovv@amsat.org, and on Compuserve HAMNET.
[Info via Luca Bertagnolio, IK2OVV, of the ITAMSAT Command Team]
* THANKS! *
===========
Thanks to all those who sent messages of appreciation regarding SpaceNews,
especially:
CT1AJY KD1NV IW2EPE N2IRO NW2L G6CNF
* FEEDBACK/INPUT WELCOMED *
===========================
Mail to SpaceNews should be directed to the editor (John, KD2BD) via any
of the following paths:
FAX : 1-908-747-7107
PACKET : KD2BD @ N2KZH.NJ.USA.NA
INTERNET : kd2bd@ka2qhd.ocpt.ccur.com -or- kd2bd@amsat.org
MAIL : John A. Magliacane, KD2BD
Department of Engineering and Technology
Advanced Technology Center
Brookdale Community College
Lincroft, New Jersey 07738
U.S.A.
<<=- SpaceNews: The first amateur newsletter read in space! -=>>
/EX
--
John A. Magliacane, KD2BD * /\/\ * Voice : 1-908-224-2948
Advanced Technology Center |/\/\/\| Packet : KD2BD @ N2KZH.NJ.USA.NA
Brookdale Community College |\/\/\/| Internet: kd2bd@ka2qhd.ocpt.ccur.com
Lincroft, NJ 07738 * \/\/ * Morse : -.- -.. ..--- -... -..
------------------------------
Date: 14 Dec 1993 13:36:04 +0200
From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!EU.net!news.eunet.fi!prime.mdata.fi!mits!mikal@network.ucsd.edu
Subject: Baycom -> Amiga
To: info-hams@ucsd.edu
Are there any softwares for Amiga-computers that work with Baycom-modem??
I found out too late that it requires a pc-computer.. I had already built it.
--
- mikal@mits.mdata.fi -
------------------------------
Date: 14 Dec 1993 09:17:55 CST
From: ftpbox!mothost!schbbs!maccvm.corp.mot.com!CSLE87@uunet.uu.net
Subject: Bravo, Bravo +, etc. pager options and programming ?
To: info-hams@ucsd.edu
Tell your paging company that you want a new dial-in number. Then, while
they are programming the new number in your pager, ask them to change th
alert beep sequence at the same time. It should be a N/C deal that way!!
BTW, no it isn't a simple thing to build the interface, and you need
some very sophisticated software to access the internal micro-P. This
software is of course copyrighted by Motorola and sold only to those who
have a good reason to get inside the pager to adjust the many features
and options. Theft of paging service is a federal crime! WA8NVW
------------------------- Original Article -------------------------
Newsgroups: rec.radio.amateur.misc
From: mwgordon@nyx10.cs.du.edu (Mike Gordon)
Subject: Bravo, Bravo +, etc. pager options and programming ?
Message-ID: <1993Dec14.012520.27012@mnemosyne.cs.du.edu>
Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
Date: Tue, 14 Dec 93 01:25:20 GMT
Lines: 41
Due to a career change, I will be back to using a pager soon. About
four years ago, I was on a Bravo, now I see that the paging companies are
pushing a variety of numeric pagers, including the Bravo + (or 2?), Bravo
Express, the Freespirit (rounded looking moto pager) and those CHEAP NEC
models. I'd like to stay with a Motorola, (I hear nothing but problems
about the NEC) but which one?
I like the time-stamp feature of the Bravo + and Express, and vibration
mode is a must, as I'm often in noisy environments. What other features do
these newer units have, and how useful are they? What options can the user
set, and what ones can be set by the dealer? Since I'm sure most dealers
don't want to go through the trouble of programming options, I'm sure they
won't tell me about all of them.
Also, has anyone figured out how to program a Bravo through the 3
contacts near the battery? (Without having to pay the paging company big
$ to do it?) A buddy of mine want's to change the his beep sound (no, not
his CAP code), and can't justify the $25 his paging company wants just to
plug it in and hit a few keys on their computer. He has a PC, and can
make a cable / interface if it isn't too overly complicated. Gee, could
it just bee a 3 wire serial connection?
On a more serious note, last time I was on a pager, my call-in number
used to be occupied by a "dealer". (And I don't mean a used car dealer.)
As I worked third shift and often slept during the day, (and will be again,
oh joy of joys) I didn't enjoy the calls at noon from his old customers.
Does anyone have any little hints on how to avoid this? Please don't
suggest having my boss call me at home during my sleeping hours, because
that would mean I'd have to plug my phone in and get woke up by tele-
marketers. (At least they don't call pagers!)
By the way, the rep from the paging company could only suggest turning
off the pager while I slept. Kind of defeats the purpose of having a pager
when you're on call around the clock, and missing a call means losing a
shift.
Thanks in advance for any help,
Mike Gordon N9LOI mwgordon@nyx.cs.du.edu
------------------------------
Date: Mon, 13 Dec 1993 16:30:42 GMT
From: elroy.jpl.nasa.gov!usc!math.ohio-state.edu!caen!malgudi.oar.net!mercury.wright.edu!buddy!gsmith@ames.arpa
Subject: HELP!!ANYBODY WORK N8PPZ?
To: info-hams@ucsd.edu
Due to a hard drive crash I have lost most on my loggbook contact files.
My backup copy only contained the first 85 or so, but I have had a few
hundred. I would like to rebuild the log if I could, so if anybody
worked me on HF please send me a note, QSL cark, or paket mail.
Thanks
-73- De Greg, N8PPZ
Internet= Gsmith@discover.wright.edu
Paket= N8PPZ@KC8TW
fidonet, Dayton ham echo as well
------------------------------
Date: Tue, 14 Dec 1993 02:44:04 GMT
From: amd!amdahl!thunder!ikluft@decwrl.dec.com
Subject: How to find the answers to frequently-asked questions about Ham Radio
To: info-hams@ucsd.edu
Posted-By: auto-faq 3.1.1.4
Archive-name: ham-faq-ptr
How to find the Rec.radio.amateur.misc Frequently Asked Questions list
------------------------------------------------------------------------------
This article will tell you how to find the answers to frequently-asked
Questions (FAQ) from rec.radio.amateur.misc. The FAQ articles are posted on
the 7th of each month. This article is posted on the 14th, 21st, and 28th of
every month as a reminder of where to find the FAQ.
The FAQ articles are 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.
Besides the monthly posting, the FAQ is always available via anonymous FTP
and from e-mail servers. This article contains instructions for obtaining a
copy of the FAQ. It also contains the table of contents from the FAQ so
that you know which questions are covered by it.
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.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.)
--How to obtain a current copy of the FAQ-------------------------------------
There are 3 ways to obtain a copy of the FAQ.
1) NetNews
2) Anonymous FTP
3) An Electronic Mail Server
Option #1: NetNews
------------------
If you are familiar enough with NetNews to look through previous articles on
your system, Option #1 above may be the easiest for you. The FAQ is posted
so that it should not expire from your site's news spool until the next one is
posted. Unfortunately, some news administrators do not honor the expiration
dates meant to preserve the FAQ.
Look in rec.radio.amateur.misc, rec.radio.info, rec.answers, or news.answers.
If the FAQ has expired at your site, try Option #2 (and ask your news
administrator to honor expiration dates for articles cross-posted to
news.answers if he/she can.)
Option #2: Anonymous FTP
------------------------
Anonymous FTP uses the File Transfer Protocol. It is only available to sites
which are directly connected to the Internet. If you don't know how to use
FTP and can't find a friend to help you, continue to Option #3. If your site
is not connected to the Internet, you should also continue to Option #3.
The following sites have copies of the FAQ:
site name & address path to FAQ articles
------------------- --------------------
ftp.amdahl.com pub/radio/amateur/faq.[1-3].Z
located in western USA, FAQ updated daily
ftp.cs.buffalo.edu pub/ham-radio/faq_ham_[1-3]
located in eastern USA, FAQ updated monthly
rtfm.mit.edu pub/usenet/news.answers/radio/ham-radio/faq/part*
located in eastern USA, FAQ updated monthly
contains news.answers archive - most UseNet FAQs are here
grivel.une.edu.au pub/ham-radio/buffalo/ham-radio/faq_ham_[1-3]
located in Australia, FAQ updated monthly
(Ham files mirrored from buffalo/funet/ucsd daily)
nic.funet.fi pub/ham/info/faq_ham_[1-3]
located in Finland, FAQ updated monthly
Remember, when connecting to the remote system, use the login name of
"anonymous" and, as a courtesy to the site administrators, your e-mail address
for the password.
Option #3: Electronic Mail Server
---------------------------------
If you can't use Options 1 or 2, your only remaining option is electronic mail.
You can retreive a copy of the FAQ by sending a message to
mail-server@rtfm.mit.edu
The body of your mail will contain a command for the mail server software.
To get all of the FAQ (consisting of 70K of e-mail in 3 parts), place the
following in the first line of your message:
send usenet/news.answers/radio/ham-radio/faq/*
Leave out the subject of your message because the mail server will ignore it.
--- begin sample mail message ---
To: mail-server@rtfm.mit.edu
From: me@here.org
Date: Mon Aug 14 22:27:33 PDT 1995
send usenet/news.answers/radio/ham-radio/faq/*
--- end sample mail message ---
------------------------------------------------------------------------------
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)
--Submitting changes for the FAQ----------------------------------------------
If you have comments or updates for the FAQ, send e-mail to
hamradio-faq@amdahl.com
This will send mail to all the people on the FAQ editorial review group.
------------------------------
Date: Tue, 14 DEC 93 00:02:50 EST
From: noc.near.net!news.delphi.com!usenet@uunet.uu.net
Subject: Need Jan '78 Ham Radio magazine
To: info-hams@ucsd.edu
contact Bill Welch, W6DDB, 45527 3rd St. E., Lancaster, CA 93535-1802.
He has just about all issues of everything. I think he gets about 3 bucks for
the issues, About covers postage.
de N6WR
------------------------------
Date: 14 Dec 1993 08:39:09 CST
From: ftpbox!mothost!schbbs!maccvm.corp.mot.com!CSLE87@uunet.uu.net
Subject: TVI weirdness
To: info-hams@ucsd.edu
------------------------- Original Article -------------------------
From: ehare@arrl.org (Ed Hare - KA1CV)
Newsgroups: rec.radio.amateur.misc
Subject: Re: TVI weirdness
Date: 13 Dec 93 00:53:32 EST
Organization: American Radio Relay League
Lines: 66
In rec.radio.amateur.misc, tjf@beta.lanl.gov (Thomas J. Farish) writes:
>The Cable TVI saga continues.
>Well, it turned out that there was no longer any problem (so far) on any
>band but 10m (a definate improvement, but still...)
>
>Anyway, The weirdness is this. I tried several power levels with him on
>the phone to report problems and he could only hear me on SSB! I turned
>down the power to about 1 watt and he could still hear SSB on channel 13,
>but 90+ watts on CW - no problem!
It sounds like you are dealing with audio rectification. CW has
no audio associated with it, although I would imagine that you would
hear various thumps in the speaker as CW is keyed.
The high-pass filter you built is usually not necessary in cable-tv
installations. I usually recommend a common-mode choke as the best
all-round cure. Buy an FT-240-43 ferrite core. Install it by wrapping
about 10 turns onto the core, just before the cable hooks up to
the first electronic device in the system (set-top converter, VCR
or cable-ready TV). You can also purchase a common-mode choke.
The FT-240-43 core is available from Ocean State Electronics
401-596-3080. A common-mode choke is available from Starplex,
314-423-5756 (part-time business).
You might also try a common-mode choke and/or AC line filter (Radio
Shack catalog #14-1111) on the ac-line cord (TV, VCR or set-top
converter).
The ARRL Technical Information Service has several EMI/RFI information
packages available. Paper copies are available from the ARRL Technical
Department Secretary, 225 Main St., Newington, CT 06111. Send
a 9"X12" SASE with 3 units of US postage for each package required,
or send $2.00 each and we will send them postpaid. If you want one for
free, send a report of the particulars of your EMI problem to
ehare@arrl.org, AND a specific request for one or more of
the applicable packages.
EMI/RFI Package - obtain this one plus any of the others
EMI/RFI - bibliography
EMI/RFI - CATVI - Reprint from Communications Technology
EMI/RFI - Computer
EMI/RFI - Electrical
EMI/RFI - Telephone
The paper files have some information that cannot be made electronic,
such as the ARRL EMI/RFI Pamphlet for the non-technical neighbor.
Most of these are also available on our ARRL Electronic Mail Server,
info@arrl.org. Send it a request, with HELP in the text of the
message.
This information has been prepared as a membership service by the
ARRL Technical Information Service.
73, Ed
-----
Ed Hare, KA1CV ehare@arrl.org
American Radio Relay League
225 Main St.
Newington, CT 06111 My posts and views do not necessarily
(203) 666-1541 - voice represent the policy of the ARRL,
ARRL Laboratory Supervisor but I can probably get in trouble
RFI, xmtr and rcvr testing for them anyway!
-----
------------------------------
Date: Tue, 14 Dec 1993 15:12:20 GMT
From: netcomsv!netcom.com!greg@decwrl.dec.com
To: info-hams@ucsd.edu
References <DTD8Dc3w165w@mystis.wariat.org>, <2ear03$ssg@panix.com>, <1993Dec13.170402.29209@ke4zv.atl.ga.us> p
Subject : Re: ARRL's callsign admin position
In article <1993Dec13.170402.29209@ke4zv.atl.ga.us> gary@ke4zv.atl.ga.us (Gary Coffman) writes:
>
>This is a perfect example of the old boy network in action. The "cabinet"
>
>The problem with the League structure as I see it is that it's a
>one party state controlled mainly by the apparatchiki.
^^^^^^^^^^^^
Wow. Cool word. Extra credit on that one, Gary :-)
Anyway, it seems to me that this whole argument (The League is bad vs.
it's your League) is being looked at too ideally, and Gary is spot-on
when he points out that politics do come into play.
As I pointed out to someone else, the trouble with 'majority rules' is
that the 'majority' doesn't always take into acount the interest of
the 'minority.' Worse yet, the 'majority' usually is not a 'plurality,'
but in fact is the group with the 'majority' of the power.
One of the reasons you have representative government is to give those
who govern the leeway to exercise discretion and to occasionally look
out for the minority that didn't elect them. Really good government is
one which does what is fair, and doesn't always implement the 'majority'
agenda.
The strength of representative government is that there is stability,
and change happens in a slow, controlled way. The weakness of
representative government is that there is stability, and change is
often hard to implement as quickly as we'd like it... ...sometimes we
give up first.
Greg
------------------------------
Date: Tue, 14 Dec 1993 15:08:25 GMT
From: netcomsv!netcomsv!cirrus!csparc046!ebs@decwrl.dec.com
To: info-hams@ucsd.edu
References <1993Dec9.162128.12183@ke4zv.atl.ga.us>, <1993Dec11.002450.28476@cirrus.com>, <1993Dec13.201605.22337@ll.mit.edu>
Subject : Re: hypochondriac scared of cancer!
In article <1993Dec13.201605.22337@ll.mit.edu>, wjc@ll.mit.edu (Bill Chiarchiaro) writes:
|>
|> In article <1993Dec11.002450.28476@cirrus.com>, ebs@csparc046.cirrus.com (eric smith) writes:
|> |>
|> |> ...stuff deleted...
|> |>
|> |> 3. Ground wave reflections add in phase with the incident wave.
|> |> As soon as the wave travels 70ft or so we will have ground
|> |> wave reflections and standing waves.
|> |>
|> |> ...stuff deleted...
|> |>
|> |> 3. Total power density PD = PI + PR(reflected power) = 2*PI
|> |>
|> |> ...stuff deleted...
|> |>
|>
|>
|> Since we're dealing with coherent fields, wouldn't the total field
|> strength be doubled, giving a quadrupling of the power density?
|>
|>
|> 73
|>
|> Bill Chiarchiaro N1CPK
|> wjc@ll.mit.edu
Bill,
You are right. Constructive interference would cause the fields to double
thus quadrupling the power. Thanks for pointing this out. I seem to
do this often when dealing with power.
As others have pointed out, the actual field pattern would probably have
a major lobe pointed towards the horizion, thus reducing the probability
of 100% constructive interference at the ground 100ft from the antenna.
So I still think it would be unlikely to have power densities greater than
50uW/cm^2 in the dorm room.
After all of this analysis it would be great to have an actual field strength
measurement from the dorm room :-).
73,
Eric
* * * * * * * * * * * * * * * * *
* ^ *
* Eric Smith <+> *
* Design Engineer v *
* Crystal Semiconductor *
* Austin, Texas *
* (512) 442-7555 X 363 *
* ebs@crystal.cirrus.com *
* *
* * * * * * * * * * * * * * * * *
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End of Info-Hams Digest V93 #1468
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