Antenna article

Thu Jul 25 16:43:58 EDT 1996

     Haven't seen the article, but nobody has yet pointed out the problem 
     with Statement #1 below.  According to Walt Maxwell, W2DU, in his 
     excellent book "REFLECTIONS, Transmission Lines and Antennas" the 
     radiator of an antenna system need not be of a self-resonant length 
     for maximum resonant current flow, the feed line need not be of any 
     particular length, and a substantial mismatch at the junction of the 
     line and the antenna does not prevent the radiator from absorbing all 
     of the power available at the junction. 

     73, Tad, NZ3I

______________________________ Reply Separator _________________________________
Subject: Antenna article
Author:  W8JITom at aol.com at INTERNET
Date:    7/25/96 7:17 AM

Subject: Kurt, help us please!
From: w8jitom at aol.com (W8JI  Tom)
Date: 24 Jul 1996 22:32:38 -0400

I've just read the most interesting antenna article I've ever read. August 
CQ, Antennas and Digital communications. I think everyone will enjoy this 
article, especially Kurt N. Sterba. I can't wait 'til he sees it! 

Among the highlights are the following bits of wisdom:

1.) An antenna must be a resonant length to radiate efficiently. 

     snip...

>From wb7dhc at nwlink.com (Jim Aguirre)  Thu Jul 25 19:54:56 1996
From: wb7dhc at nwlink.com (Jim Aguirre) (Jim Aguirre)
Date: Thu, 25 Jul 1996 11:54:56 -0700 (PDT)
Subject: Antenna article
Message-ID: <Pine.GSO.3.94.960725115155.8760A-100000 at washington>

This was obviously the April 1997 issue which somehow got out early.
Just in case it wasn't, however, I'm going to install a backpressure gauge in
my 9913 to be sure the radio waves are getting through!

On Thu, 25 Jul 1996 W8JITom at aol.com wrote:

> Subject:	Kurt, help us please!
> From:	w8jitom at aol.com (W8JI  Tom)
> Date:	24 Jul 1996 22:32:38 -0400
> 
> I've just read the most interesting antenna article I've ever read. August
> CQ, Antennas and Digital communications. I think everyone will enjoy this
> article, especially Kurt N. Sterba. I can't wait 'til he sees it! 
> 
> Among the highlights are the following bits of wisdom:
> 
> 1.) An antenna must be a resonant length to radiate efficiently. 
> 
> 2.) Due to the mirror image...the greater the antenna's height, the
> greater its gain.
> 
> 3.) An antenna has the same pattern on receive and transmit ONLY if the
> elements and feedline have the same impedance.
> 
> 4.) Making the antenna thicker lowers both Q and gain. Making the antenna
> thinner raises Q and gain.
> 
> 5.) Q is determined solely by the ratio L and C in the antenna.
> 
> 6.) The reason 468/f is used instead of 492/f is because of a K factor
> related to the ground. If the wire was in space 492/f would work just
> fine.
> 
> 7.) A quad provides improved rejection of terrestrial noise over a Yagi.
> 
> 8.) With any beam antenna of any beamwidth you get another 3 dB by
> stacking another beam exactly 1/2 wl away.
> 
> 9.) Coax feedlines MUST be cut to a multiple of 1/2 wl or the antenna will
> not work because of backpressure.
> 
> 10.) Coax feedlines must be the correct size because, like a pipe and a
> water pump, if too large or to small they won't match the pump. The
> electricity will slow down and maybe even stop and bounce backwards in
> waves. Both the diameter and length of the pipes feeding our antennas are
> important. They have to match the flow, so they can't be too big or too
> small....too long or too short.
> 
> I wonder if anyone else enjoyed this article as much as I did?
> 
> 73 Tom
> 
> 
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> From: w8jitom at aol.com (W8JI  Tom)
> Newsgroups: rec.radio.amateur.antenna
> Subject: Kurt, help us please!
> Date: 24 Jul 1996 22:32:38 -0400
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>From wd8rin at gate.net (Bill Loviska)  Thu Jul 25 23:26:31 1996
From: wd8rin at gate.net (Bill Loviska) (Bill Loviska)
Date: Thu, 25 Jul 1996 18:26:31 -0400
Subject: cq article
Message-ID: <2.2.32.19960725222631.0072fa70 at pop.gate.net>

Just last week the reflector was informed that digital communications were
better than cw, now we all can read why.  

>From ea1au at jet.es (EA1AU)  Thu Jul 25 22:52:41 1996
From: ea1au at jet.es (EA1AU) (EA1AU)
Date: Thu, 25 Jul 1996 22:52:41 +0100
Subject: EU077 on RSGB IOTA Test
Message-ID: <1.5.4.32.19960725215241.00693bcc at jet.es>

        Next weekend (27/28 July) the BATEA IOTA TEAM will be activing EU077
(Salvora Island) during
the RSGB IOTA Contest. The call will be ED1MC and we will operate Multop /
Mix Mode (SSB / CW).

Some notes about the rigs are:

Transceiver: Kenwood TS940
Linear: TL922
Antennas: 5 El monobanders for 10/15/20. Half wave vertical for 40 and Delta
Loop fpr 80.

The operators are: EA1AKB, EA1AKP, EA1AU, EA1DD, EA1MC, EA1EVN, EA1BNW
The QSL manager for ED1MC (1994/1995/1996) is EA1MC (We confirm 100 % via
Bureau/Direct).

We will be glad to get you through the pile-up!

73 from BATEA IOTA TEAM

>From dougp at wku.campus.mci.net (Doug Perkins)  Fri Jul 26 05:04:17 1996
From: dougp at wku.campus.mci.net (Doug Perkins) (Doug Perkins)
Date: Thu, 25 Jul 1996 23:04:17 -0500
Subject: Antenna switch and loss
Message-ID: <199607252304.SAA22671 at wku-01.campus.mci.net>

        I'm preparing for the fall contest season and I need to move my
station to another room due to some space limitations.  A potential problem
is the lack of coax to the new location.  I would like to install a remote
coax switch for HF.  If I install it at the base of my tower (40 ft) I can
use the existing coax and not buy new cable.  Is it necessary (relative to
line loss) to install the switch as close to the beam as possible ?  Also, I
will not have enough exsisting coax for my 2M beam (which I exclusively use
for the local dx cluster)for the new run.  Any idea what the line losses
would be if I made the distance up with a barrel connector in line for the
2M antenna ?  I'm using RG8 for feeding both the hf antennas and 2M beam
which are located about 100 feet from the house.
                                TIA,
                                        Doug (KF8VS)   