QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940332.txt

Internet Message Format | 1994-11-13 | 12KB

Date: Wed,  5 Oct 94 04:30:19 PDT
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Subject: Ham-Ant Digest V94 #332
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Ham-Ant Digest              Wed,  5 Oct 94       Volume 94 : Issue  332

Today's Topics:
                   'No ground' verticals? (3 msgs)
                      15m phased vertical array
                    5/8 wve 'mirror mount' wanted.
              Anybody ever use Phillystran "big grips"?

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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: Tue, 4 Oct 1994 16:52:11 GMT
From: [e-mail] (Daniel T Senie)
Subject: 'No ground' verticals?

In article <36ra19$[e-mail]>,
Jukka Tapio Sirvi| <[e-mail]> wrote:
>In article <[e-mail]> [e-mail] (Alan Cooney) writes:
>>I'd like to make a 'no ground' vertical antenna for six meters (to
>
>The vertical doesn't need radials, if you make it 1/2 wave length long. You
>have match the impedance though since it isn't 50 ohm (can't recall now
>how much it is).
>
>Jukka OH6DD

Commercial antennas include the Cushcraft AR-6 and a Diamond
base/repeater antenna. The Cushcraft is 1/2 wavelength long,
and is essentially similar to all the rest of the ringos. It works just fine.

The Diamond is colliniar and is 21 feet tall.

J- poles for 6 meters are not hard to build. Use a choke (sleeve) balun
on the coax directly below the feetpoint for best results.

A vertical dipole (bring the coax away at 90 degrees) also works well.

Dan N1JEB
--
---------------------------------------------------------------
Daniel Senie                 Internet:     [e-mail]
Daniel Senie Consulting                    [e-mail]
508-779-0439                 Compuserve:   74176,1347

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

Date: 4 Oct 1994 10:16:09 GMT
From: [e-mail] (Jukka Tapio Sirvi|)
Subject: 'No ground' verticals?

In article <[e-mail]> [e-mail] (Alan Cooney) writes:
>I'd like to make a 'no ground' vertical antenna for six meters (to

The vertical doesn't need radials, if you make it 1/2 wave length long. You
have match the impedance though since it isn't 50 ohm (can't recall now
how much it is).

Jukka OH6DD

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

Date: 4 Oct 1994 11:53:08 GMT
From: [e-mail] ()
Subject: 'No ground' verticals?

Alan,

What you are looking for is a endfed half wave dipole.
the problem with this setup is, that the feed point
impedance is very high, and hence requires a well designed
matching transformers. Commercial systems for 2 or 10 m
are the Ringo antennas, where there is a one turn loop
with adjustable tap at the lower end of the radiating element.

An alternative are those 1/4 wl verticals with a coaxial sleeve
instead of the radials.

Beware of some designs like Jpoles, some of them require 50 Ohms symmetric
feed.

73, Morritz DL5UH

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

Date: 4 Oct 1994 17:44:02 -0400
From: [e-mail] (Ricecakes)
Subject: 15m phased vertical array

I'm looking for a design for a 2 element 15m phased vertical array with
1/8 wavelength separation and 135 degree phasing (which according to the
ARRL antenna book, would give me 4.2dB)

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

Date: 4 Oct 1994 13:01:10 GMT
From: [e-mail] (John Kedziora)
Subject: 5/8 wve 'mirror mount' wanted.

Im looking for a 5/8 wave 2m antenna that'l mount on my truck's mirror,
(the kind that are 6x10 with tubular supports above and below)

Real estate on the roof is limited at best.

Does anyone have/reccomend one?

cost is important (i.e. low cost :))



please reply by e-mail.


thanx~



John Wu3c


([e-mail])

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

Date: Tue, 4 Oct 1994 16:11:18 GMT
From: [e-mail] (Pete Rossi)
Subject: Anybody ever use Phillystran "big grips"?

Anyone out there ever use the new "big grips" that are now available for
Phillystran cable?  They cost roughly double what the standard end kits
cost.  Is it worth the extra cost?

=================================================================
Pete Rossi - WA3NNA                  [e-mail]

Unisys Corporation - Government Systems Group
Valley Forge Engineering Center - Paoli, Pennsylvania
=================================================================

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

Date: Tue, 4 Oct 1994 16:32:28 GMT
From: [e-mail] (Daniel T Senie)

References<[e-mail]> <36q6d6$s60$[e-mail]>, <36rleb$[e-mail]>
Subject: Re: Antennas are prohibited ...!!!!!!..

In article <36rleb$[e-mail]>,
Todd Little <[e-mail]> wrote:
>
>In article <36q6d6$s60$[e-mail]>, TI Forum <[e-mail]> writes:
>|>Don't WE think it is about time we come out of the ATTIC and
>|>STAND up for our rights!!!!!
>|>I am also stuck with antenna prohibitions. I would like to fight.
>|>Alone it will not work ... but as a group!!!!
>|>i think we need to lobby our elected officials. Gather support
>|>from other Amateur Radio Operators in similar situations.
>|>No I don't propose my home owners association allow me to put up
>|>a 40M beam on a town house.   or Stacked 15 element 2M beams. But
>|> out the the ATTIC reduces RFI.
>|>Well any one elese feel this way!!!
>
>Please feel free to lobby anyone and everyone.  I've personally written
>much of the League's hierarchy and the only really favorable response I
>got was from Wilson.  Sumner went out of his way to suggest that we need
>to work with local officials and demonstrate our value.  The fact that
>the local RACES (of which I'm an active member), and many disaster related
>agencies spoke on our behalf, the local egomaniacs (you know, our local
>elected government) still felt that our town shouldn't live under the
>specter of high or large or numerous antennas.  Dealing with a bunch
>of self appointed demi-gods doesn't always work.
>
>Personally I beleive this is one of the biggest threats to amateur radio,
>but I guess those that already have their contest station antenna farms
>don't have to worry about it.

It is interesting to read nearly identical threads over in rec.video.satellite
as people start exploring the new small-dish satellite TV, only to discover
that their towns prohibit ALL outside antennas. In the case of TV, this
makes the Cable TV company a virtual monopoly (guess who pushed for such
regulations in many towns?).

As the fight for TV roof antennas and dishes moves forward, it is important
for the hams to be there supporting in the fight. Ideally, we need to
get all such ordinances, covenants, etc. removed, and the vehicle to get
them gone may well be the "Information Superhighway". Much of the future
of communications will be wireless, be it satellite or terrestrial, and
antennas will have to be a part of the landscape.

Dan N1JEB

--
---------------------------------------------------------------
Daniel Senie                 Internet:     [e-mail]
Daniel Senie Consulting                    [e-mail]
508-779-0439                 Compuserve:   74176,1347

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

Date: 4 Oct 1994 04:44:45 GMT
From: [e-mail] (Lou Nigro)

References<QE8C2CDD@bxc604> <36iluf$[e-mail]>, <36pl01$[e-mail]>
Subject: Re: using twin coax vs ladder line

Tom WB7ASR ([e-mail]) wrote:

: Lou

: At the bauln outside your house, I assume your tieing the center
: conductor of each coax to the bauln's output terminals, however what do you do
: with the sheilds, tie them together to ground or let them float? When you run
: the two coax cables to the antenna, did you just tape them together? Is there
: any critical spacing? At the feed point of the antenna, does the sheilds float?
: Did you use 50 or 75 ohn coax, or doesn't it matter?

: This idea sounds interesting, I have a ton of 50 ohm surplus coax and I might
: give it a try.


Tom -

The center conductors are connected to the baluns output terminals and
the grounds at the bauln end are grouded.  The bauln is enclosed in a
metal box that has 3 SO-239 connectors on it, 1 for the input to the
bauln from the tuner, and the other 2 for the balanced outputs from the
bauln.

At the antenna end, the shields are tied together and not connected to
anything else.

No critical spacing, and you can run the coax wherever you want to, even
bury it if you must.  I used RG-8/U, you can use 75 ohm stuff as well
with a change in impedance.  50 ohm coax will have an impedance of about
100 ohms, 75 ohm coax will be about 150 ohms.

The new ARRL antenna book has a short writeup on shielded parallel lines,
page 24-18.

Losses will be higher than with open wire, but I have a short run and
reduced noise, longer life, and easier installation of the feed line more
than make up for this in my case.

The feedline has been in use for 10+ years in Tucson and it is still
working just fine.  The antenna, a full wave horizontal delta loop cut
for 80 meters, is used on 40 meters as well, on occasion with a Drake L4B
linear with no problems at all.

Lou Nigro - KW7H

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

Water can be toxic if you hold your head under it long enough -

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

Date: Tue, 4 Oct 1994 19:31:10 GMT
From: [e-mail] (Zack Lau (KH6CP))

References<[e-mail]> <36q6d6$s60$[e-mail]>, <36rleb$[e-mail]>
Subject: Re: Antennas are prohibited ...!!!!!!..

Todd Little N9MWB ([e-mail]) wrote:

: Please feel free to lobby anyone and everyone.  I've personally written
: much of the League's hierarchy and the only really favorable response I
: got was from Wilson.  Sumner went out of his way to suggest that we need
: to work with local officials and demonstrate our value.  The fact that
: the local RACES (of which I'm an active member), and many disaster related
: agencies spoke on our behalf, the local egomaniacs (you know, our local
: elected government) still felt that our town shouldn't live under the
: specter of high or large or numerous antennas.  Dealing with a bunch
: of self appointed demi-gods doesn't always work.

Some hams have solved this problem by serving on the town planning board
to balance things out a little.

: Personally I beleive this is one of the biggest threats to amateur radio,
: but I guess those that already have their contest station antenna farms
: don't have to worry about it.

It seems that the hams who have done poorly in court cases haven't stacked
the deck in their favor by spending a lot of time on emergency/public service
activities. For example, the people at the South Pole really appreciate
phone patches back home--something you usually need a really big 20 meter
antenna to do well.


--
Zack Lau  KH6CP/1           2 way QRP WAS
                           8 States on 10 GHz
Internet: [e-mail]   10 grids on 2304 MHz

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End of Ham-Ant Digest V94 #332
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