rotating, not at all steady. If listening to the two antennas
tanks. This means copying the first time through, rather than asking
for repeats. Listening to the circular polarization would have the
This was pretty clear listening to the weaker EU signals. The
the ability to transmit at low angles, or some such. Completely
> Just as a heads-up for anyone interested in this subject -- in the December
> QST just now arriving in subscribers' hands, there is a cool article on X-O
> circular polarization (CP) antennas. The author (Eric Nichols, KL7AJ)
> discusses the fact that all F-layer ionospheric propagation is actually
> circular and arrives at the receiving antenna by way of one of two different
> refraction paths, depending on... well, you can read the article for the
> theoretical details. He says all of this has actually been well understood
> in physics and radio engineering circles since the 1930s, but (with a few
> exceptions) has had scant mention in the ham radio literature.
>
> The executive summary is that you can build a receive antenna (which
> empirically demonstrates and proves the theory) consisting of two inverted
> vee antennas constructed around a central support, with the four legs
> arranged accurately such that the slopes of the legs are all identical, the
> angles between the legs are all 90 degrees, and the two feedlines (connected
> through identical baluns) are precisely the same length. By then inserting a
> 1/4-wavelength (90 degree) delay line in one dipole's feedline and then
> adding the signals together through a T or some more sophisticated combiner,
> you will get either a large increase in signal strength with respect to
> either dipole individually, OR a commensurately large loss of signal
> strength with respect to either dipole individually -- depending on which
> variety of circular polarization (X-wave or O-wave) you are getting from the
> station being received at the moment.
>
> This is one kind of orthogonal receiving antenna that could have very
> practical uses on the HF bands, especially if you have a diversity-capable
> receiver such as the K3.
>
> One possibility I can think of: You could set up two separate X-O inverted
> vee antenna systems on two separated support masts, each magnetically
> aligned as described in the article, with one antenna set up for X waves and
> the other set up for O waves. Connect the X-wave configured antenna to one
> receiver, the O-wave configured antenna to the other receiver. And say
> goodbye to a lot of the QSB normally associated with F-layer-propagated
> reception! (At least it seems to me that it would have that effect.)
>
> Another possibility: use ultra-fast PIN diode switching of the 90-degree
> delay line and reconstruct both an X and O output from a single antenna.
> Since even PIN diodes probably can't switch faster than, say, one cycle at
> 14 MHz (about 72 nanoseconds), I don't know if this would work, as you would
> be switching multiple cycles and fractions of cycles (asynchronously) back
> and forth... Would this matter? You would end up with a 3-dB loss on each
> leg, but that in itself should be trivial; absolute sensitivity is not an
> issue at HF. But would the chopped-up waves be properly demodulated in the
> receivers?
>
> This is about where the engineering of it goes over my head... Comments?
>
> Bill W5WVO
>
>
> -----Original Message-----
> From: Ken Alexander
> Sent: Friday, November 12, 2010 15:16
> To: Elecraft Reflector ; Lee Buller
> Subject: Re: [Elecraft] Education please
>
> OK, I guess the ham application for an orthogonal antenna would be to use
> two loops at 90 degrees to each other. With the electronic trickery I
> mentioned below you would have yourself a dandy direction finding antenna.
> Great for transmitter hunts and tracking down jammers and other bad guys.
>
> 73 - Ken
>
>
>
> --- On Fri, 11/12/10, Ken Alexander <
[hidden email]> wrote:
>
> From: Ken Alexander <
[hidden email]>
> Subject: Re: [Elecraft] Education please
> To: "Elecraft Reflector" <
[hidden email]>, "Lee Buller"
> <
[hidden email]>
> Date: Friday, November 12, 2010, 10:04 AM
>
> This is subject to much correction from people who are smarter than me, but
> my oversimplified description is that an orthogonal antenna basically
> consists of three loop antennas oriented in three planes that are at right
> angles to each other (X, Y and Z axes if you remember your basic geometry).
> The antenna are bidirectional in each of those planes.
>
> With some associated electronic wizardry, you can compare the signals
> received by each antenna and establish the direction (in three-dimensional
> space) of a given transmitter. Sort of a method of electronic
> triangulation.
>
> I don't know how much application it has in ham radio. I don't recall
> seeing any ham call signs associated with the documents I read during my
> Google search! It looks like most of the uses are industrial.
>
> Hope that gets you started, and like I said, probably subject to some
> clarification by brainier people.
>
> 73,
>
> Ken Alexander
> VE3HLS
>
>
>
> --- On Fri, 11/12/10, Lee Buller <
[hidden email]> wrote:
>
> From: Lee Buller <
[hidden email]>
> Subject: [Elecraft] Education please
> To: "Elecraft Reflector" <
[hidden email]>
> Date: Friday, November 12, 2010, 9:32 AM
>
>
>
> What the heck is a orthogonal antenna? Would someone define it or give an
> example? I have Googled it but it is all mumbo-jumbo to me.
>
> Lee Buller
> K0WA
> Still learning after all these years!
>
> In our day and age it seems that Common Sense is in short supply. If you
> don't
> have any Common Sense - get some Common Sense and use it. If you can't find
> any
> Common Sense, ask for help from somebody who has some Common Sense. Is
> Common
> Sense divine?
>
> Common Sense is the image of the Creator expressing revealed truth in my
> mind.
> - J. Wolf
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