QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940322.txt

Internet Message Format | 1994-11-13 | 16KB

Date: Tue, 27 Sep 94 04:30:23 PDT
From: Ham-Ant Mailing List and Newsgroup <[e-mail]>
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Subject: Ham-Ant Digest V94 #322
To: Ham-Ant


Ham-Ant Digest              Tue, 27 Sep 94       Volume 94 : Issue  322

Today's Topics:
                   2 Meter SWR meter schematic????
                   2m vertical in my tree - how to?
                   cell phone directional antenna?
                            Discone + whip
             Grounding and Lightning Protection (3 msgs)
                         NEC from DXF files?
                        Slinky antenna anyone?
                         Wanted Cushcraft R-3
              What is a Good Satillite Antenna (2m/440)
                       Yagi Antenna for UHF TV

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

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: Mon, 26 Sep 1994 13:02:24 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!gatech!wa4mei!ke4zv![e-mail]
Subject: 2 Meter SWR meter schematic????
To: [e-mail]

In article <[e-mail]> Mike Lyon <[e-mail]> writes:
>
>does anyone out there by chance have a schematic for a swr meter for 2
>meters? or know of a place where i can get one?

The RSGB VHF UHF Book has a project that makes one out of some standard
copper plumbing fittings and some hobby shop brass. I built it, it works
about as good as a Bird if you build and calibrate it carefully. It's the
perfect thing to leave in-line all the time. However, Radio Shack, of all
people, sells a nice little portable instrument that works fine at 2 meters.

Gary

--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | emory!kd4nc!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | [e-mail]
Lawrenceville, GA 30244     |                     |

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

Date: 26 Sep 1994 02:19:17 -0700
From: nntp.crl.com!crl.crl.com![e-mail]
Subject: 2m vertical in my tree - how to?
To: [e-mail]

[e-mail] (Bob Bronson) writes:

>The highest point of my lot is an oak tree.  It is a good 20' higher than
>my roof peak.  Two reasons for considering placement in the tree are: 1)
>homeowners assoc. prohibits antennas on roof, & in tree it will be
>somewhat hidden.  2) it's there and higher already.  Has anyone made tree
>installations?  I would interested in hearing about it.  I would expect a
>slight loss being mounted against a 5-8" dia. live tree trunk compared to
>free air.  I'm looking at something like the Cushcraft ringo ranger 2
>vertical.  Thanks for any comments,

>Bob B.    KE4PGM    [e-mail]

I have a pine tree in my yard that has been topped off for reasons
unknown.  I placed a ringo ranger 2 on a radio shack pipe giving an
antenna about 70 feet up.  I was careful to clear the top of the tree.
When I mounted it, I found two small (3 in. diameter) limbs, and used a
chimney mount kit (radio shack) to mount the vertical pole about 18
inches from the main tree. This allowed for fine tuning the vertical
positioning of the antenna.  The ringer ranger 2 at 70 feet is very good.

mick
(ac6eu)

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

Date: Mon, 26 Sep 1994 17:13:55 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!cs.utexas.edu!sdd.hp.com!col.hp.com!srgenprp![e-mail]
Subject: cell phone directional antenna?
To: [e-mail]

[e-mail] ([e-mail]) wrote:

: IH>[e-mail] meinte am 09.09.94
: IH>zum Thema "Re: cell phone directional antenna?":

: IH>> >Does anyone have plans for a homebuilt directional cell antenna?

: Try locating a program called Yagimax.  It is a Yagi antenna design
: program.  The problem you'll have will be in matching the |Z| of the
: antenna connector and line loss in you coax.  Keep it short (coax) and
: have fun.  73's DE N5UJJ Jeff

  You might be interested in a design I did which is located on
  col.hp.com  ~/hamradio/packet/n6gn/antennas

  A first pass of a 902-928 MHz design I did from the NBS data was
centered at about 850 MHz and should make a pretty decent antenna in
that range.  The gain bandwidth of the antenna itself is practically 100
MHz, this from measurement of a pair of them with a network analyzer
over a reasonable antenna range.  The bandwidth of the match is not bad,
I used a folded dipole feed with impedance transformation, but not as
wide as that of the antenna itself.  Still I suspect that it would be
very usable in that range even with a little mismatch loss included.
Fabrication is from standard copper water pipe and 1/8" brazing rod.

 BTW, yagimax does not appear to accurately predict the performance of
this antenna.  I didn't do the simulation myself so can't comment more
except to say that I have high confidence in the results since multiple
measurements were made in a variety of ways over paths of 50' to 75
miles.  These measurements were in close agreement and showed the 13-15
dBi sort of performance that the NBS data predicted.


Glenn Elmore n6gn

amateur IP:    [e-mail]
Internet:    [e-mail]

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Date: Mon, 26 Sep 1994 10:09:27 GMT
From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!vixen.cso.uiuc.edu!newsfeed.ksu.ksu.edu!moe.ksu.ksu.edu!osuunx.ucc.okstate.edu![e-mail]
Subject: Discone + whip
To: [e-mail]

    Could someone tell me the best way to attach a whip antenna to a

Radio Shack (20-013) discone?  Need to get those lower freqs.  Thanks

for any help.

            merlin-  <[e-mail]>

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

Date: Mon, 26 Sep 1994 12:45:26 GMT
From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!gatech!wa4mei!ke4zv![e-mail]
Subject: Grounding and Lightning Protection
To: [e-mail]

In article <364v0l$[e-mail]> [e-mail] (Kenneth E. Harker) writes:
>      I've become very interested in how to provide the best ground and
>lightning protection for my station.  I am living in my fraternity this
>year, and would very much not like to see it get fried because of my
>amateur radio activities.

>      * I cannot install a bulkhead panel or anything like that.

>      B Use something like a PolyPhaser IS-50NX in the coax.  My big
>question
>        is where in the chain to put this?  Should I put it outside my
>room,
>        say at ground level, and bolt it to a ground rod there, and
>have
>        another run of coax back up to my room?  Or make a wooden
>"bulkhead"
>        to fit in the bottom of my window sill and drop copper strap
>down to
>        ground?  Is it not a really bad idea to have the protector
>inside the
>        room?  Is wood a poor choice of insulator for this application?

Yes you can install a bulkhead panel, but you'll have to make it.
Just make a metal panel (instead of wood) that will fit in the window
with the window closing down on it. A rack panel, or a chassis box can
be used, in a wooden frame if necessary to fit the window. Bring your
coax through that panel with a NEMP series suppressor, and run your
ground strap from the panel down to your ground rod (bury as much copper
as you can along the side of the house containing the rod. It doesn't
have to be real deep.)

Use that metal panel in your window as your station single point
ground. Tie your power third wire to the panel too, and use a
power line suppressor at the panel if you can afford it. (I strongly
recomend this.)

This isn't perfect, but it's about the best you can do short of
doing it right. If you keep everything reasonably straight and
well bonded, it should give good protection.

Gary
--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | emory!kd4nc!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | [e-mail]
Lawrenceville, GA 30244     |                     |

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

Date: 26 Sep 1994 20:02:26 GMT
From: pa.dec.com!nntpd.lkg.dec.com!iamu.chi.dec.com![e-mail]
Subject: Grounding and Lightning Protection
To: [e-mail]

In article <[e-mail]>, [e-mail] (Gary Coffman) writes:

|>Yes you can install a bulkhead panel, but you'll have to make it.
|>Just make a metal panel (instead of wood) that will fit in the window
|>with the window closing down on it. A rack panel, or a chassis box can
|>be used, in a wooden frame if necessary to fit the window. Bring your
|>coax through that panel with a NEMP series suppressor, and run your
|>ground strap from the panel down to your ground rod (bury as much copper
|>as you can along the side of the house containing the rod. It doesn't
|>have to be real deep.)

I've heard comments before to the effect that your ground rods should be
deep.  How important is that?

Also, is there any reason not to use 3/4" type L (the medium weight stuff)
copper pipe?  I've found that in general I can drive a 10' section into the
ground and it costs less than a 1/2" or 5/8" plated ground rod.  I would
think it would out last and out perform a plated ground rod any day (although
driving it in rocky soil might be a problem.)

On a slightly related issue, what is adequate for ground connections.  I've
seen everything from #10 aluminum wire to 1" or greater tinned braid
suggested.  Is #8 or #6 copper adequate?   Or is the braid from old RG-8
sufficient?

|>Use that metal panel in your window as your station single point
|>ground. Tie your power third wire to the panel too, and use a
|>power line suppressor at the panel if you can afford it. (I strongly
|>recomend this.)

What's a "power line suppressor"?

|>This isn't perfect, but it's about the best you can do short of
|>doing it right. If you keep everything reasonably straight and
|>well bonded, it should give good protection.

How does one bond something?  I can find no reference to bonding in
any of my handbooks.

Just looking to improve my grounding and lightning protection.

73,
Todd
N9MWB

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

Date: Mon, 26 Sep 1994 19:42:10 GMT
From: svc.portal.com!sdd.hp.com!hpscit.sc.hp.com!icon![e-mail]
Subject: Grounding and Lightning Protection
To: [e-mail]

Gary Coffman ([e-mail]) wrote:
: Use that metal panel in your window as your station single point
: ground. Tie your power third wire to the panel too, and use a
: power line suppressor at the panel if you can afford it. (I strongly
: recomend this.)

Won't you have problems with ground loops when you hook the house 3rd wire to
a second ground?  It's already grounded once at the service entrance, which in
my case is clear on the other side of the house.

Also, by "power line suppressor at the panel" do you mean the service panel,
or your tin box in the window.  If it's the tin box, how do you hook it up?

Thanks,

Greg  KD6KGW

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

Date: Mon, 26 Sep 1994 18:23:32 GMT
From: svc.portal.com!sdd.hp.com!col.hp.com!csn![e-mail]
Subject: NEC from DXF files?
To: [e-mail]

I am about to launch into writing a program to convert .DXF graphics file
(most CAD programs output to this format) into wire lists for the
Numerical Electromagnetics Code.  I have two questions:

1. Has it already been done and sitting out there somewhere?

2. If it's not, would anybody be interested in it as shareware (cheap)

Feel free to e-mail your answers. Thanks....

 --
Brent G DeWitt ([e-mail])
TUV Product Service
Boulder, CO USA
phone [phone] fax [phone]

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

Date: 25 Sep 1994 15:14:16 -0400
From: ihnp4.ucsd.edu!swrinde!gatech!mailer.acns.fsu.edu!freenet3.scri.fsu.edu!freenet3.scri.fsu.edu![e-mail]
Subject: Slinky antenna anyone?
To: [e-mail]

References: <35tnrj$[e-mail]>

Subject Slinky Antenna:
These are available at Antennas West  1500 North 150 West
Provo, Utah    84605.

[e-mail]

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

Date: Mon, 26 Sep 94 13:48:47 -0500
From: news.delphi.com![e-mail]
Subject: Wanted Cushcraft R-3
To: [e-mail]

I am looking for a Cushcraft R-3 vertical in decent shape for a
decent price.
Please reply to [e-mail]

73...DAVE

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

Date: 26 Sep 1994 13:57:07 GMT
From: news1.hh.ab.com!cle.ab.com![e-mail]
Subject: What is a Good Satillite Antenna (2m/440)
To: [e-mail]

Need recommendation of a good Satillite antenna.  Is the cushcraft
AOP-1 good?  Or should I go for HyGain OSCARlink antenna.  I have
a friend who is selling the  AOP-1 for $80.

Also can I use this antenna system for UHF/VHF SSB contesting?


Please E-Mail at above address!


73,

Brian

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

Date: 26 SEP 94 16:22:29
From: pa.dec.com!mrnews.mro.dec.com!est.enet.dec.com![e-mail]
Subject: Yagi Antenna for UHF TV
To: [e-mail]

In article <[e-mail]>, [e-mail] (David Malecki) writes...
>I have had relatively good results with a yagi that I built from plans
>in the ARRL handbook ('89 I think).
>
>My questions are:
>- does scaling work (I think it should)

Yes.

>- would changing from aluminum tubing to solid aluminum (for the
>reflector and directors) make a big difference in desired lengths (or general
>  performance)

No. Think "skin effect". Most of the RF energy is very, very close to the
surface, anyway.

>- how much performance (if any) would I loose by using a conducting
>boom such as aluminum (I'm currently using a wooden dowel,

Not much. The center of Yagi elements is at a null, so it doesn't matter that
much what you attach it to. ARRL's Antenna Book has some sample Yagis built
with and without attachment to a conducting boom, and it does make a small
difference in the length of the elements for absolute best results.

>- is it worth going to a larger (more elements) antenna for a little
>extra gain?  The picture is stable, and definitely watchable, but
>definitely snowy too.

Depends... you need a MUCH bigger antenna to make a big difference in received
signal. An unfortunate fact of antennas - the first 10dB of gain aren't too
tough, the next 10dB, however...    A preamp might help.

-Tom R.   N1OOQ   [e-mail]

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End of Ham-Ant Digest V94 #322
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