[time-nuts] Antenna question about RHCP/LHCP I'm sure a time-nut can answer

[Chuck Harris]

To quote Jasik's treatment of Kraus's work:

"There are two kinds of circular polarization, right-hand, and left-hand.  Either
type may be generated by a helical beam antenna, depending on the manner in which
the helix is wound.  A helix wound like a right-hand screw radiates or receives 
right-hand circular polarization..."

Pretty clear in Jasik.  I have to believe that Kraus was able to make a statement
with a similar level of clarity somewhere in his book... but I don't have a copy
on hand to test my beliefs.

As to the thread handedness:  That is pretty old terminology that has been around
since the first blacksmith tried to describe how he made his screws to another
blacksmith.

In any case, the "handedness" of a circularly polarized wave is really just a
convention.  If the person discussing the principal understands the principal,
he should arrive at descriptions that are self consistent.  Believing that a
RHCP antenna transmits with a right hand helix, and receives with a left hand
helix is not being consistent.  Either the frame of reference is inconsistent,
or the understanding is inconsistent.

Right?

-Chuck Harris

PS, I don't see this as arguing, just two friends having a discussion.

Rex wrote:
> I took a scan through Kraus "Antennas" since he did much of the definitive work on
> Helical antennas. In his chapter on Wave Polarization he gives a mathematical
> definition of Left- and Right-circular polarization, then quickly mentions that the
> IEEE definition is the opposite. He has a footnote: "This IEEE definition is opposite
> to the classical optics definition."
>
> So it seems our current antenna engineering uses the IEEE definition for RHCP and
> LHCP, but earlier work on EM wave theory had defined right-circular and left-circular
> exactly reversed from IEEE. So, combine that with the reflection flipping and it is
> not hard to think why there might be confusion.
>
> I looked all around for a simple definition of the RH, LH quality of the wave from a
> helix antenna. I assume I might have extracted it from pages of formulas and
> theoretical explanations, but why not just clearly state it in a book that is largely
> about helical antennas. Somewhere else (in Kraus) I read that the IEEE definition of
> a RHCP or LHCP wave from or to a helical antenna had the same handedness as the helix
> of the antenna. Unfortunately in that writing he did not bother to explicitly mention
> what he meant by the handedness of a helix. I assume he meant it to be the same as
> the handedness of a screw, but he didn't say that, so once again, a missed opportunity.
>
> I'm not arguing with you, Chuck, just pointing out why there might be room for
> confusion in some circles. (Pun intended.)
>
>