QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940244.txt

Internet Message Format | 1994-11-13 | 13KB

Date: Sun, 31 Jul 94 04:30:15 PDT
From: Ham-Ant Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Ant Digest V94 #244
To: Ham-Ant


Ham-Ant Digest              Sun, 31 Jul 94       Volume 94 : Issue  244

Today's Topics:
                      20m dipole problems  HELP
                      Feedline next to 220V run
                       Feed lines and AC power
                             Inverted V's
                   Jupiter decametric emission info
                             kc7csk reply
                           Log Periodics ?
                          Novice's question

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Archives of past issues of the Ham-Ant Digest are available
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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: 30 Jul 1994 08:08:03 -0400
From: newstf01.cr1.aol.com!search01.news.aol.com![e-mail]
Subject: 20m dipole problems  HELP
To: [e-mail]

In article <31bkjm$[e-mail]>, [e-mail] (Jay Kesterson
K0GU) writes:

Hey How about a 20 m vertical on some other part of the house/property?
I've seen plenty of inexpensive construcion articles inQST,CQ, and 73
magazines. It would be also be a good learning experience. Good Luck and
73

Carlos Herrera N2OIZ

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

Date: Fri, 29 Jul 1994 23:49:46 GMT
From: news.pipeline.com!malgudi.oar.net!utnetw.utoledo.edu!uoft02.utoledo.edu![e-mail]
Subject: Feedline next to 220V run
To: [e-mail]

In article <30oriu$[e-mail]>, [e-mail] (Herb Sims) writes:
>You shouldn't have to go to this length.  The reason being the coax, if it
>is of good quality, is shieled. i.e. no RF in or out of the coax.  So you
>don't really need the torroids, etc.
>
>Herb

Herb,
The torroids are probablly not needed, true - but I live in an imperfectly
matched (ie the real) world.  For the few $$ to do that, I'd buy the
extra RF supression the coils provide.  I know the ideal coaxial cable
is perfectly shielded *provided* it is infinately long, and constructed
with linear isotropic homogeneous materials.

Just my nits to pick - I've taken one too many electricity & mag. classes
lately.

Patrick
KB8PYM

Good planets are hard to find, and I can prove it!
[e-mail]       UT-Ritter Observatory

I speak just for me.  Sometimes I just speak.

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

Date: Sat, 30 Jul 1994 00:03:25 GMT
From: news.pipeline.com!malgudi.oar.net!utnetw.utoledo.edu!uoft02.utoledo.edu![e-mail]
Subject: Feed lines and AC power
To: [e-mail]

In article <30tsi0$[e-mail]>, [e-mail] writes:
>Greetings!
>
>I'm getting ready to dig a deep trench from my house to my barn (120') to
>get water and power out there.  The barn is in the middle of a large pasture,
>and is also very close to where I plan to put a tower some day.  My question
>is this.  Would there be any problem in running some coax out to the barn
>in the same trench?  The water and power will be enclosed in 4" PVC pipe
>and come in through the basement wall.  I was thinking of putting in
>another pipe and running coax, etc. through it.  Any thoughts?
>
>Thanks!
>
>-Brian n8wrl
>[e-mail]

Brian,
Sounds like a reasonable thing to me.  While you are doing it, why not do
it up right - run really good coax in a conduit and let's see - cable
TV coax, phone, UTP ethernet cable  string for the tin can phones when
all the hi tech stuff quits working.

Seriously, I'd run as much stuff as possible now and run a few pull strings
for the future.  You might find you spend a lot of time in your barn if
the rest of the family gets too loud and your shack, tv, phone, ect
are available there.

Patrick
KB8PYM

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

Date: Sat, 30 Jul 94 15:09:17 PDT
From: portal.com!portal!cup.portal.com![e-mail]
Subject: Inverted V's
To: [e-mail]

First of all, I would like to thank everyone for their assistance in my
query about 2m->6m Yagi beam seperation.
COntinuing with my project, I currently have a 1/2w dipole cut for
75m up 50 feet. I am looking at building a Inverted V cut to a full
wave (1/2w on a leg) with the apex up 90 feet. From experiences and
theories, will such a project yield better results than the dipole?
Also, from my readings, would a full wave yield better results than
a half wave for a Inverted V? I do not intend to use this antenna
for any other bands other than 75m/80m CW.
In the same vein, am I overlooking any other 'DX' antennas I could
build with my single 100ft tower as a support? I have the room to
stretch out (55 acres) but no supports (trees, towers, poles) other
than the single 100 footer and a 50 foot TV tower next to the house.
Thanks!  73  Al   N9ISN   [e-mail]

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

Date: Sat, 30 Jul 1994 00:16:03 GMT
From: ihnp4.ucsd.edu!news.acns.nwu.edu!math.ohio-state.edu!howland.reston.ans.net!europa.eng.gtefsd.com!swiss.ans.net!malgudi.oar.net!utnetw.utoledo.edu!uoft02.utoledo.edu![e-mail].
Subject: Jupiter decametric emission info
To: [e-mail]

In article <[e-mail]>, [e-mail] (Matthew Francey) writes:
>[e-mail] (Paul Harden) writes:
>>Here is some basic information regarding Jovian decametric emissions to
>>help answer some of the questions thus far raised on the net.
>
>excellent post!
>
>>                              If the signal comes from space, it will
>>   strike each antenna about the same time; if it comes from earth, the
>>   signal will slide across the antennas one-at-a-time.  Thus, only
>>   coherent signals (those arrive about the same time) are processed as
>>   coming from space.
>
>what is the general configuration of these arrays?  and i don't see what is
>preventing a on-earth signal from arriving at the array in a manner
>similar to what is expected for an off-earth signal.  does this means that
>the arrays are absolutely mindbogglingly gigantic, or most of the terrestrial
>noise one receives has a source fairly close to the array?  or some
>other reason?
>--
>Matthew Francey                     [e-mail]            [e-mail]
>"live before you die"               GPS(NAD27): N43o34.210' W079o34.563' +0093m
Matthew,
next time you are at a pond, pool or other large body of water, drop a pebble
in and observe the ripples near the point of impact and then at a distance
much much farther out (greater than 15 wavelengths should be plenty).

The waves near the point of impact will be curved alot in a small area,
while the waves farther out show less curvature over the same area (not the
same solid angle ;-)  )

The radio emissions from Jupiter (or anywhere else in space) are essentially
plane parallel waves by the time they reach the Earth when taken over such
a small area.  The radio waves from sources on Earth would be much more
curved (like the ripples close to the source) and so will sweep across the
array.

Hope I've not confused you too much!  I know I've confused me  :-)

Patrick
KB8PYM
Astronomer in Training
(Graduate student @ Univ. Of Toledo)

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

Date: 30 Jul 94 15:58:27 GMT
From: [e-mail]
Subject: kc7csk reply
To: [e-mail]

To Richard Harris, kc7csk
Richard - put your e-mail address in the message & I'll reply
directly.  Basically, do not skimp on the mobile antenna if you
plan to lots travel, etc and use the radio.  Get 5/8 wave type and
hard mount it.  QST has had several reviews on the dual band mobiles
and that would be your best source to get REAL data on the rigs.
--
73
===========================================================
Robert Wood
WB5CRG
[e-mail]        (blkbox is NOT blackbox, inc.!)
[e-mail]@menudo.uh.edu
============================================================

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

Date: Sat, 30 Jul 1994 00:05:45 GMT
From: news.pipeline.com!malgudi.oar.net!utnetw.utoledo.edu!uoft02.utoledo.edu![e-mail]
Subject: Log Periodics ?
To: [e-mail]

In article <[e-mail]>, [e-mail] (nick button) writes:
>HI,
>Does anybody know where I can find a program for a PC that
>will allow me to design a log-periodic ?
>
>I have a very old textbook with graphs and formulae, surely
>these days there must be something that does it by computer !
>
>Thanks,
>
>
>Nick G4IRX
>==========================================
>| Nick Button,       Nottingham, England |
>| Internet:- [e-mail].    |
>==========================================
>
I have a Lotus spreadsheet I grabbed from somewhere to design LP antennas.
If you are interested let me know & I'll email it.  If others are interested
let me know and I'll post it.

Patrick
KB8PYM

Why am I always the last to know?

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

Date: Fri, 29 Jul 1994 23:35:46 GMT
From: news.pipeline.com!malgudi.oar.net!utnetw.utoledo.edu!uoft02.utoledo.edu![e-mail]
Subject: Novice's question
To: [e-mail]

In article <[e-mail]>, [e-mail] (James M. Statzer II) writes:
>I hope this is the correct place to post my following questions and
>apologize ahead of time if it is not.
>
>I am interesting in whether it is possible to increase the range of FM
>reception of my present home stereo in order to pick up programs not
>carried in my local area.  If so, how much of an increase can I expect and
>at what cost?  The guy at Radio Shack said all they had (10 amp) would
>increase my range about 30 miles on a good night, with ideal conditions,
>and probably while standing on my head whistling Dixie. Is this the best I
>can hope for?
>
James,
Radio shack does sell an FM broadcast band antenna that is directional for
$16.95 - it looks like a mid-sized TV antenna.  Other options would be
some type of pre-amplifier for the FM band.  I would go the better antenna
route if at all possible.  If you could put one of them up 20 or 30 feet
(or use one of the combo TV VHF-UHF-FM antennas at that height) you will
get much better results than with the indoor type antennas I've seen (and
used) sold for stereo systems.

Just my personal $0.01 - I can't afford $0.02

Patrick
KB8PYM

Good planets are hard to find, and I can PROVE it!

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

Date: 29 Jul 1994 23:56:14 GMT
From: news.acns.nwu.edu!math.ohio-state.edu!howland.reston.ans.net!gatech!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!charnel.ecst.csuchico.edu!xmission![e-mail]
To: [e-mail]

References <310mc0$[e-mail]>, <3127hb$[e-mail]>, <[e-mail]>tech
Subject : Re: What coax feed to use for 2m antenna


>
>        Have you ever tried 9880? We had lots of this stuff laying around from
>  an old ethernet network. I was always curious if this would also be very
>  good. it's 50 Ohm. looks like a Urathane dialectic. solid copper conductor
>  (looks about 12 gauge). a foil layer followed by a 95%+ stranded weave
>  followed by another foil layer followed by yet another 95%+ stranded weave.
>


The problem with it is that it uses SOLID conductor and therefore would be
likely to fail if there is any motion (such as wind or connecting and
disconnecting radios).
For 100 feet, the higher lose gr-5 will do fine.  The extra 1 dB will never
be noticed.  Under 50 feet, rg-58 will do fine.  The slight extra loose
will not be seen.

Sandy

KB7YSQ

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End of Ham-Ant Digest V94 #244
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