QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940303.txt

Internet Message Format | 1994-11-13 | 19KB

Date: Sat, 10 Sep 94 04:30:16 PDT
From: Ham-Ant Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Ant Digest V94 #303
To: Ham-Ant


Ham-Ant Digest              Sat, 10 Sep 94       Volume 94 : Issue  303

Today's Topics:
                 300ohm twinlead, outdoors? (4 msgs)
               cell phone directional antenna? (2 msgs)
                   Coaxial into the House (2 msgs)
                Info on Autek SWR/Z/L/C Meter (2 msgs)
          Please Help: Putting a Mobile Antenna on my House
                   SETIQuest Magazine - Exobiology
                      Two Beverages - Revisited
                        UK source for ELNEC ?

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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: Thu, 8 Sep 94 19:07:53 GMT
From: ihnp4.ucsd.edu!ucsnews!newshub.sdsu.edu!nic-nac.CSU.net!charnel.ecst.csuchico.edu!yeshua.marcam.com!news.kei.com!ub!galileo.cc.rochester.edu!uhura.cc.rochester.edu![e-mail]
Subject: 300ohm twinlead, outdoors?
To: [e-mail]

In article <[e-mail]> [e-mail] writes:
>
>Hi Rich! What you might consider is fabricating your own twin-lead from
>two identical lengths of coax, RG-58 is fine. Ground the shields at the
>tuner end but let them float at the feedpoint to avoid a groundloop.
>This will give you the necessary environmental protection for several
>years. I live in a townhouse and use this method to feed my attic
>antenna from a basement shack. BTW, the feedline does not have to be
>taped together, each side can find it's own path to the antenna as long
>as the individual lengths are identical. Also, you can use any
>impedance, 50, 75 or ?ohms makes no difference. Good luck! NF0R, Dave

Interesting suggestion.  I am curious about a couple of points:
*  If you do not run them together, and if the only currents are in the
   center conductors of the two coax, then the range over which the feedline
   will couple with other conductive objects will be large. This would
   imply a larger chance of RFI.
*  If there are currents on the shield of the wires, as would be my guess,
   then you will again have rfi, unpredictable load impedance and a distorted
   radiation pattern.

My guess would be that make this work, you would have to take the same
degree of care with its layout and symmetry as you would with simple
old 12 swg wire.  Why spend the money on expensive coax to simulate a
plain ole simple open line?

Rajiv
aa9ch/2

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

Date: Sat, 3 Sep 1994 17:31:50 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!swrinde!elroy.jpl.nasa.gov!wvus!pelican!ent-img.com!wb6hqk![e-mail]
Subject: 300ohm twinlead, outdoors?
To: [e-mail]

In article <[e-mail]>,  <[e-mail]> wrote:
>Hi All:
>
>   A quick question:  I'm thinking of putting up a dipole, fed with
>300ohm TV twin-lead, and routed through a transmatch to my QRP rig.
>Since I live in an apartment, I'll have to bury the twin-lead to avoid
>having the maintenance people run over it with the lawnmower, etc.  :-)

I hope this really is a joke!  The property which makes twinlead very
low attenuation is that the majority of the fields are in the essentially
lossles air outside the lossy plastic dielectric.  The price you pay is
the requirement that the line be run at least a couple of inches away from
anything, especially conductors.  Don't bury it!!!  Coax may have more
loss but since the fields are completly contained within the outer conductor
of the cable it may be buried and run next to metal objects.  Even the best
normally available is quite a bit lossier at HF than good quality
twinlead but if you can keep the SWR reasonably low you should get good
results.  Can you arrange a trap dipole?


bart

[e-mail]

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

Date: 9 Sep 1994 07:41:04 -0400
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!spool.mu.edu!howland.reston.ans.net!swiss.ans.net!newstf01.cr1.aol.com!search01.news.aol.com![e-mail]
Subject: 300ohm twinlead, outdoors?
To: [e-mail]

In article <[e-mail]>, [e-mail] writes:


--------------------------------------------------------------------------
---------------------------
Hi Rich! What you might consider is fabricating your own twin-lead from
two identical lengths of coax, RG-58 is fine. Ground the shields at the
tuner end but let them float at the feedpoint to avoid a groundloop.
This will give you the necessary environmental protection for several
years. I live in a townhouse and use this method to feed my attic
antenna from a basement shack. BTW, the feedline does not have to be
taped together, each side can find it's own path to the antenna as long
as the individual lengths are identical. Also, you can use any
impedance, 50, 75 or ?ohms makes no difference. Good luck! NF0R, Dave
--------------------------------------------------------------------------
----------------------------

Hi dave, any idea of the charachteristic impedance obtained?  I've read
about this before, and it seems pretty interesting.  I've got some old
aircore 90 ohm (?) coax I might try this with--it's cheap (free) and i've
got enough of it.

72, jim n0oct

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

Date: Fri, 9 Sep 1994 14:59:06 GMT
From: ihnp4.ucsd.edu!pacbell.com!sgiblab!swrinde!howland.reston.ans.net!vixen.cso.uiuc.edu!newsfeed.ksu.ksu.edu!moe.ksu.ksu.edu!osuunx.ucc.okstate.edu!master.ceat.okstate.edu!gcouger@network.
Subject: 300ohm twinlead, outdoors?
To: [e-mail]

In article <34phkg$[e-mail]>,
JimN0OCT <[e-mail]> wrote:
>In article <[e-mail]>, [e-mail] writes:
>
>
>--------------------------------------------------------------------------
>---------------------------
>Hi Rich! What you might consider is fabricating your own twin-lead from
>two identical lengths of coax, RG-58 is fine. Ground the shields at the
>taped together, each side can find it's own path to the antenna as long
>as the individual lengths are identical. Also, you can use any
>impedance, 50, 75 or ?ohms makes no difference. Good luck! NF0R, Dave
>
>Hi dave, any idea of the charachteristic impedance obtained?  I've read
>about this before, and it seems pretty interesting.  I've got some old
>aircore 90 ohm (?) coax I might try this with--it's cheap (free) and i've
>got enough of it.

The impedance is twice the impedance of the coax and the loss is unchanged.
So only used the doubled feed line where you must and get back to
twin lead as soon as you can. Probably the only advantage in using coax
twin lead is the increase in puncture voltage.

I used to have a zep made up out of coax twin lead and it worked pretty
good.

Good luck
Gordon AB5DG
Gordon Couger senior software specialist
   Biosystems & Agricultural Engineering. 114 AG Hall Stillwater, OK 74075
   [e-mail] 405 744 9763 day 625-2855 evenings

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

Date: 9 Sep 1994 17:18:15 GMT
From: ihnp4.ucsd.edu!pacbell.com!sgiblab!spool.mu.edu!torn!news.unb.ca!nbt.nbnet.nb.ca!nbcc1.nbnet.nb.ca![e-mail]
Subject: cell phone directional antenna?
To: [e-mail]

I am in a very fringe area for cell phone use.

Although I can hit 2M repeaters further away (with 5W) my 3W bag phone used
at home is just shy of holding the tower.

Does anyone have plans for a homebuilt directional cell antenna?

Thanks,

Steve Patriquen
VE9 PIX

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

Date: Fri, 9 Sep 94 15:10:48 -0500
From: news.delphi.com![e-mail]
Subject: cell phone directional antenna?
To: [e-mail]

Steve Patriquen <[e-mail]> writes:

>I am in a very fringe area for cell phone use.
>
>Although I can hit 2M repeaters further away (with 5W) my 3W bag phone used
>at home is just shy of holding the tower.
>
>Does anyone have plans for a homebuilt directional cell antenna?

Perhaps a dumb question. Why not use a land line telephone at home?

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

Date: Fri, 9 Sep 1994 18:07:43 GMT
From: ihnp4.ucsd.edu!pacbell.com!sgiblab!spool.mu.edu!howland.reston.ans.net!usc!nic-nac.CSU.net!charnel.ecst.csuchico.edu!csusac!zimmer!zimmer.csufresno.edu![e-mail]
Subject: Coaxial into the House
To: [e-mail]

Well, I finally bought a 2 mt. external antenna which I already installed.  I
live in a fairly new house whose (outside) walls are covered with stucco
(sp?).  All windows have aluminum frames.  Before I start drilling the stucco
and/or the windows' frames I thought in asking to you'all about feeding
coaxial through the walls and/or windows.  Please send me a line or two.

73 de Rafael, KE6JSR


PS: Also I would like to split the cable into two endings (one for the radio
shack and one for my bedroom).  Where should I put the splitter? Inside the
house, or, close to the antenna?  Does it matter?


*******************************************************************
Rafael Solis, Professor        Craig School of Business
[e-mail]    California State University, Fresno
[phone]            [phone] (Fax)
*******************************************************************

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

Date: Fri, 9 Sep 1994 19:21:55 GMT
From: wang![e-mail]
Subject: Coaxial into the House
To: [e-mail]

[e-mail] (Rafael Solis) writes:

>PS: Also I would like to split the cable into two endings (one for the radio
>shack and one for my bedroom).  Where should I put the splitter? Inside the
>house, or, close to the antenna?  Does it matter?

Are you talking about using this antenna for transmitting, or just for
use with a scanner?  You cannot use a "splitter" like the kind TVs use
if you are going to transmit.  You can use something like an "A/B"
switch, though.

Dave, KZ1O



--
Dave Bushong
OPEN/image Recognition Products

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

Date: 8 Sep 1994 17:28:35 GMT
From: nntp.crl.com![e-mail]
Subject: Info on Autek SWR/Z/L/C Meter
To: [e-mail]

Lou Genco ([e-mail]) wrote:
: In article <[e-mail]>,
: [e-mail] (Jeremy A. Donimirski) wrote:

: > Does anyone own one of these Autek meters?  If so, do you like it?  How well
: > do the various functions work?  Is it convenient to use?
Can you use this unit also as a frequency meter?


--
[e-mail] |
AB6MB         |            PEOPLE BEFORE PROFITS!!!!!
          |


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

Date: 8 Sep 1994 22:57:05 -0400
From: newstf01.cr1.aol.com!search01.news.aol.com![e-mail]
Subject: Info on Autek SWR/Z/L/C Meter
To: [e-mail]

In article <34nhk3$[e-mail]>, [e-mail] (Jeff Jones) writes:

>Can you use this unit also as a frequency meter?


No.  YOu can use it as somewhat of an RF signal generator, although it is
too unstable for that use.

72, jim n0oct

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

Date: 9 Sep 1994 16:05:51 GMT
From: pa.dec.com!nntpd.lkg.dec.com!iamu.chi.dec.com![e-mail]
Subject: Please Help: Putting a Mobile Antenna on my House
To: [e-mail]

In article <[e-mail]>, [e-mail] writes:
|>In article <34m42l$[e-mail]>, [e-mail] (Todd Little) writes:
|>>I'm not sure which Diamond that antenna is.  If it is a 5/8 wave antenna on
|>                                                 ^^^^^^^^^^^^^^^^^^^^^^^^
|>>2 meters and something similar on 70cm, then you don't need a ground plane.
|>                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|>Sorry to burst your bubble, but a 5/8 wave antenna really should have a
|>ground plane for reasonable pattern and performance.  A 1/2 wave (or integer
|>multiple thereof) doesn't.

Ooops, nothing like posting late in the evening without the brain fully
engaged.  You're absolutely correct.  Thanks for pointing that out.

73,
Todd
N9MWB

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

Date: 8 SEP 94 18:00:03 EST
From: pa.dec.com!nntpd.lkg.dec.com!mtwain.enet.dec.com![e-mail]
Subject: SETIQuest Magazine - Exobiology
To: [e-mail]

        SETIQuest is a new quarterly print/electronic mail (E-mail)
    periodical containing news, technical information, and tutorials
    devoted to bioastronomy and its subset, SETI (Search for
    Extraterrestrial Intelligence).

        SETIQuest is published for professionals, serious amateur
    astronomers, and individuals curious about this fascinating field of
    observation.  SETIQuest fills the need for a specialized astronomical
    publication devoted exclusively to the on-going search for evidence
    of life in the Universe.  Such evidence could be intentional or
    inadvertent signals of other civilizations.  Such evidence could be
    found in spectral signatures of biological activity on extrasolar
    planets or in the interstellar medium.

        SETIQuest is written and edited for the scientifically literate
    individual taking part in the progress of our technological
    civilization, with articles by amateur and professional scientists.
    SETIQuest includes information about hands-on observational programs
    that can be carried out by individuals and groups of amateur
    astronomers at radio and optical wavelengths.

        SETIQuest is filled with articles covering topics such as:

        * Tutorials about bioastronomy and SETI
        * Microwave or optical SETI as practiced by amateurs
        * "Do-it-yourself" participation in bioastronomy and SETI activities
        * Book reviews
        * Regular commentary on issues relevant to SETI and bioastronomy:

        SETI and the political milieu

        Philosophical issues regarding the prospects of success and
    failure in the search

        SETI as a parable of science versus pseudo science

        Publications Watch:  Summaries of recent scientific/general
    publications relevant to SETI

        For your FREE issue of SETIQuest (Volume 1, Number 1), send us
    your postal address by fax, E-mail, or conventional mail to:

        SETIQuest Inquiries, Department EX
        Helmers Publishing
        174 Concord Street
        Peterborough, NH  03458-0874
        Telephone: [phone]  FAX [phone]
        Internet E-mail: [e-mail]

    --------------------------------=|=---------------------------------------
    Carl Helmers,  President & Editorial Director,  Helmers Publishing, Inc.
       --< Publishers of Sensors, ID Systems and SETIQuest magazines >--
                 (what else do you do after starting BYTE?)
    INTERNET:  [e-mail]
    SNAILMAIL: 174 Concord Street, Peterborough, NH 03458
    PHONE:     [phone]            -=-  FAX: [phone]

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

Date: 8 Sep 1994 19:44:06 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!math.ohio-state.edu!sdd.hp.com!col.hp.com!fc.hp.com![e-mail]
Subject: Two Beverages - Revisited
To: [e-mail]

[e-mail] wrote:
: .....request for help w/a newly erected 2 wire Beverage.

: Has anyone used a termination at the far end that consists of a
: transformer as per Misek's book on the subject?  If so, could
: you share  your experiences with me.  Do you find the antenna
: as good as a terminated single-wire antenna.  My experience has
: been (subjective) that the 2 wire doesn't perform as well in
: either direction as a single wire resistor terminated affair.

: 73 de Walt Kornienko  -   K2WK

I tried one a few years ago. I have a copy of Misek's book and made the
transformer as described. The beverage seemed to hear well but the front-
to-back wasn't very good. When you talk to ops who have tried a two wire
beverage it seems about half think they are great and half didn't have
much luck.

73, Jay K0GU                  [e-mail]

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

Date: Thu, 8 Sep 1994 10:01:41
From: agate!doc.ic.ac.uk!cs.city.ac.uk!city!pcmail.nerc-bas.ac.uk![e-mail]
Subject: UK source for ELNEC ?
To: [e-mail]

Does anybody know of a UK distributor for the ELNEC program ?

Cheers Mike

Mike Rose  British Antarctic Survey  [e-mail]

(Yes it is cold and no there are no polar bears)

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

Date: Fri, 9 Sep 1994 13:53:17 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!overload.lbl.gov!agate!howland.reston.ans.net!gatech!concert!hearst.acc.Virginia.EDU!cscsun![e-mail]
To: [e-mail]

References <[e-mail]>, <[e-mail]>, <CSLE87-010994183249@145.39.1.10>sun
Subject : Re: Lightning

Karl Beckman ([e-mail]) wrote:
: In article <[e-mail]>, [e-mail] (Warren Gay) wrote:

: >
: > When I last moved, I put 110VAC relays in a power distribution box for
: > this purpose. The relay switches via heavy duty contacts, 3 lines -
: > 2 - 110VAC + 1 Neutral. This of course switches the 220VAC for my
: > linear (that I don't have yet) in the process.  The relay was one of
: > two lucky finds at a ham-fest.
: >

: It's a good thing that you are located in Canada, but not safe.  Here in
: the USA you are not permitted to ever interrupt the neutral lead, since it
: is the grounded side (center, actually) of the feed.

Tell that to my water pump - the control box that came with it opens both
power-carrying conductors (not the ground, naturally).  There are exceptions
to every absolute rule, apparently.  I can't remember specifically, but there
are reasons to open the neutral.  (I'll check the NEC).
--
David Tiller                | Network Administrator | Voice: [phone]   |
[e-mail] |  n2kau/4  | Randolph-Macon College| Fax:   [phone]   |
Brady Law critique removed  | P.O. Box 5005         | ICBM:  37d 42' 43.75" N |
due to liberal PC pressure. | Ashland, Va 23005     |        77d 31' 32.19" W |

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

End of Ham-Ant Digest V94 #303
******************************