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@aol.com at INTERNET
Subject: Kurt, help us please!
From: w8jitom@aol.com (W8JI Tom)
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@nwlink.com (Jim Aguirre) Thu Jul 25 19:54:56 1996
From: wb7dhc@nwlink.com (Jim Aguirre) (Jim Aguirre)
Subject: Antenna article
Message-ID: <Pine.GSO.3.94.960725115155.8760A-100000@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@aol.com wrote:
> Subject: Kurt, help us please!
> From: w8jitom@aol.com (W8JI Tom)
>
> 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@aol.com (W8JI Tom)
> Newsgroups: rec.radio.amateur.antenna
> Subject: Kurt, help us please!
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>
>From wd8rin@gate.net (Bill Loviska) Thu Jul 25 23:26:31 1996
From: wd8rin@gate.net (Bill Loviska) (Bill Loviska)
Subject: cq article
Message-ID: <2.2.32.19960725222631.0072fa70@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@jet.es (EA1AU) Thu Jul 25 22:52:41 1996
From: ea1au@jet.es (EA1AU) (EA1AU)
Subject: EU077 on RSGB IOTA Test
Message-ID: <1.5.4.32.19960725215241.00693bcc@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@wku.campus.mci.net (Doug Perkins) Fri Jul 26 05:04:17 1996
From: dougp@wku.campus.mci.net (Doug Perkins) (Doug Perkins)
Subject: Antenna switch and loss
Message-ID: <199607252304.SAA22671@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)
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