My points when I started this were open wire can help in a bad
situation. I was not using 130' antenna, but one that was only 33'. And
I was able to get out. Which leads to my second point. Some of us live
in areas or on property that is not best suited for HF antennas, but so
what. With a little thought, a bad situation can be made to work out
pretty well. And lastly, throw something up and try it; you never know
just what might happen.
As an aside, I was surprised that I could load a 33' on 160, and more
surprised when I was actually able to get out of my state; I live in
Maryland. Morocco and Mexico where a shock. And, I will admit you can do
things during contests that are nearly impossible at other times.
Something to consider. Open wire was around almost as far back as
Marconi, and maybe he used it. It has little loss even at high SWR, far,
far less than coax in the extreme. In the olden days, no one really
worried about SWR losses. Open wire was the common transmission line.
Antenna tuners weren't really around, either.The trick that was done in
those times was to have your final amplifier's tank circuit tune to the
output frequency and act as the antenna coupler. In fact, the commercial
station on Montauk Point at the tip of Long Island used to use rhombic
antennas pointed toward Europe. The station engineer told me that the
SWR was around 14:1 and he didn't worry too much about it as the loss on
the line to his antenna was about 1 db and the a swinging link took care
of the match.
As hams in today's world, there are a few things that can be done to get
out on HF. Putting up the biggest antenna with the most gain is at the
top of the list. But, not everyone has the ability to do as some of my
friends like W3LPL, for instance, are able to do. But, there is one
thing that many hams overlook, cut the loss from your radio to the
antenna. That means use the transmission line that has the least loss
for the situation and make sure you can operate your antenna tuner, if
needed, in a range that has its losses at a minimum.
Do not worry about resonance. Most of us use antennas that if they were
resonant wouldn't reflect 50 Ohms anyway.
73,
Barry
K3NDM
------ Original Message ------
From: "Ron D'Eau Claire" <[email protected]>
To: [email protected]
Sent: 1/31/2017 11:53:49 AM
Subject: Re: [Elecraft] The "Kinda Random Antenna"
The intrinsic higher impedance of ladder line helps reduce the losses
through a lower SWR than typical coax. A center fed wire at least 1/4
wave
long end-to-end on the lowest frequency used (e.g. 130 feet on 160
meters)
and fed with typical 350 to 450 ohm ladder line will show an SWR of
10:1 or
less across the HF spectrum, since a real-world wire will show an
impedance
of only 4,000 ohms or so even when it is exactly 1/2 wavelength long.
Feeding the same antenna with 50 ohm coaxial line will result in an SWR
100:1 or greater and so much greater losses.
73, Ron AC7AC
-----Original Message-----
From: Elecraft [mailto:[email protected]] On Behalf Of
Wes
Stewart
Sent: Tuesday, January 31, 2017 5:07 AM
To: [email protected]
Subject: Re: [Elecraft] The "Kinda Random Antenna"
Sadly, this is often untrue.
Get Dan's (AC6LA) program at: http://ac6la.com/tldetails1.html and run
some
examples.
for more on ladder line see: http://k6mhe.com/n7ws/Ladder_Line.pdf
On 1/30/2017 9:00 PM, Barry wrote:
...I feed it with ladder line which has low loss even at absurdly
high
SWRs, and the tuner I use is designed to be used with antennas that
are no where near optimum.
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