Talk:Helical antenna

Equations needed
It would be nice to add design equations for each antenna type. This stuff is great reference material that usually has to be looked up all the time Madhu

I added an external link to a project we're working on. In the coming days, I'll be able to add images and possibly a polar plot diagram to better help visually explain the Helical Antenna. User:jimijames

Polarization
What is the polarization of this type of antenna in the broadside mode? I would expect it to be linearly polarized along the axis of the antenna, but I would like some confirmation.--SkiDragon (talk) 21:51, 12 April 2009 (UTC)

The broadside helical is polarized in the circular mode. It can be right hand or left hand depending on the direction of the linear windings. Most common is windings with a left hand radiation pattern as typified by the Mobile One DX160SH "Superhelical" design. In reality a left hand helical radiating to a right hand helical will see some attenuation due to the phase difference, with this being detectable only with sensitive milivolt field strength measurements. In practical situations the difference is not detectable by the end user in normal use. (124.186.65.252 (talk) 15:13, 14 October 2009 (UTC))

You have this backwards: It is the axial mode which is circularly polarised. In the Broadside mode the antenna behaves like a normal (loaded) dipole. Gutta Percha (talk)

Teminology
It is unfortunate that this article conflates the true "Helical Antenna", with what in engineering terms is referred to as a "Continuously Loaded Antenna". The two types of antenna are radically different in both form and function.

A true Helical uses the Travelling Wave principle to produce gain and directivity. Its width is a wavelength or so. It is mainly used at UHF.

A Continuously Loaded antenna has a loading coil wound along the insulated support in order to shorten the antenna. Its width is a tiny part of one wavelength. It has no gain and is mainly used at HF.

I think this confusion is caused by CB manufactures using the term Helical Whip to describe what should really be called a "Continuously Loaded" whip antenna. Gutta Percha (talk) —Preceding undated comment added 13:13, 2 March 2011 (UTC).

WikiProject banner removal
How come this article under the project WikiProject Professional sound production? I removed that banner.

R!j!n (talk) 12:24, 12 February 2013 (UTC)

Right handed vs Left handed Polarisation of Axial Mode Antenna
Has the terminology for polarisation of this type of aerial been settled ? As a teenager I can remember the debacle which emerged when the Telstar communications satellite was demonstrated for the first time on UK television. This was the first transatlantic television transmission, and was a complete failure. The reason given later, when the problem was sorted out, was that engineers on opposite sides of the Atlantic did not agree about what 'right hand circular polarisation' means. Consequently someone used the wrong kind of antenna. A bit like the Mars probe that failed because someone confused kilometers with miles (only more easily sorted).

I find the discussion of this in the main article, with its reference to the 'right hand rule' unsatisfactory and ambiguous. Are we now agreed that a helical ant in the form of a right handed screw emits right-handed circular polarised waves ? It might not be as simple as that.

For example look here

https://en.wikipedia.org/wiki/Circular_polarization

g4oep

It has been difficult, but I have now settled the question of helical form and sense of circular polarisation. The solution depended on finding two authoritative references. I have amended the text accordingly. I have also deleted the link to the right hand rule. The target of the link in the original text did not help the reader to decide whether a particular helix is left or right handed. If anyone wants to reinstate the link, it will be necessary to add some information which indicates how the rule may be applied to helices. g4oep. — Preceding unsigned comment added by G4oep (talk • contribs) 06:29, 25 May 2018 (UTC)

The call for a citation for endfire coil spacing
I am not sure that a citation is needed where it is annotated. The quarter wavelength (0.25) approximation follows directly from the 0.23 figure stated in the same sentence. If a citation is needed anywhere it should be after the 0.23 figure 123.208.225.247 (talk) 00:44, 28 June 2024 (UTC)