9 votes
Accepted

Antenna polarization when dealing with satellite communications

Satellite engineers tend to use circular polarization for two reasons: When a linearly polarized signal travels through the atmosphere there are anomalies, such as Faraday rotation, that alter the ...
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  • 18.1k
7 votes

What are the properties of the radiation of a magnetron?

I'm sorry if this answer doesn't answer your literal questions – it's just that these questions aren't strictly answerable. it is commonly known that electromagnetic radiation from an antenna is ...
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6 votes
Accepted

Which way is a yagi polarized?

For a Yagi antenna the electrical polarisation matches the mechanical orientation of the elements. So to receive your vertically polarised signals the elements of your antenna will need to be vertical ...
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5 votes

Long range HF polarization

All radio signals are polarized. You can't not polarize an HF signal. The problem with HF is often we're considering skywave propagation, which involves reflections off the ionosphere and ground. ...
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5 votes
Accepted

Why do horizontally-polarized RF waves reflect better off ground than vertically-polarized waves?

It's a well-known fact among hams who use HF frequencies that horizontally-polarized RF waves reflect better off of ground than vertically-polarized waves. This explains why ground conductivity is so ...
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  • 8,833
5 votes

Why can I receive a vertically polarized signal on a horizontally polarized antenna on HF and vice versa?

Why can I receive a vertically polarized signal on a horizontally polarized antenna on HF and vice versa? Who says you can? Cross-polarization is a common source of path loss even on HF. LZ1AQ has ...
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4 votes
Accepted

2 Meter horizontal or vertical dipole polarization?

For VHF, choice of polarization is not up to your desired radiation pattern, but who you want to be able to communicate with. In HF, the ionosphere causes random rotation of your signal's polarization,...
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  • 22.9k
4 votes

Why can I receive a vertically polarized signal on a horizontally polarized antenna on HF and vice versa?

Reflections from the ionosphere are randomly distorted from the original polarization - but not circular. Polarization matters for ground waves but not for most sky waves.
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4 votes

Long range HF polarization

From the Wikipedia article on HF: "Long-distance (skywave) receiving antennas can generally be oriented either vertically or horizontally since refraction through the ionosphere usually scrambles ...
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  • 8,922
4 votes
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Receiving the ISS SSTV: dipole antenna configuration and orientation

reports it as "U: linear, V: linear" Satellites which transmit and receive at the same time frequently do one on VHF (2m) and the other on UHF (70cm), and they frequently have separate ...
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  • 8,833
4 votes

Can I slant-polarize a bay antenna?

Welcome to HamSE, Gary, and thanks for an interesting question. We should be grateful to Russel Renaud, VA3RR, for posting his NEC2 simulation model of the DB2 antenna. Importing the model to the ...
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  • 7,685
4 votes

Why do horizontally-polarized RF waves reflect better off ground than vertically-polarized waves?

RE: "I would also like to know why vertically-polarized waves propagate much better via ground-wave propagation than horizontally-polarized waves." This subject is treated in various textbooks ...
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  • 2,872
4 votes

Coupling 2 Antennas to one line?

It may help to be familiar with the concept of scattering parameters or S-parameters. The S-parameters are the elements of a matrix which tell you the amplitude and phase coming out of every port, for ...
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3 votes
Accepted

Long range HF polarization

It is useful to use polarization of HF signals, but not for the same reasons you'd do that with a VHF signal, and the effects are radically different for groundwave vs. skywave propagation. Groundwave ...
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  • 4,203
3 votes

Are circular polarized antennas on HF subject to polarization fading?

This question is on point. Let me make a quick excursion on how we physically model the rotating effect that the ionosphere has on linear polarizations. You have elegantly shown in a previous answer ...
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3 votes

Variable polarization Yagi using two antennas on the same boom, joined together with variable feedpoint phase?

Yes, it is possible given two antennas at orthogonal angles to adjust the relative amplitude and phase between them and create vertical, horizontal, or anything between polarization. You can even ...
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3 votes

Antenna polarization when dealing with satellite communications

However, when they are pointed nearly straight up at a satellite that reference is effectively lost Satellite communications typically uses circular polarizations instead of linear (horizontal/...
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3 votes

Dual Polarization Yagi Antenna for 10 m

From what you describe, it doesn't seem the vertical elements would be fed at all. Since they pass directly through the plane of symmetry of the horizontal elements they experience no electric field ...
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2 votes

Does antenna width/shape affect resonant frequency like length does?

Yes, width and shape are relevant. It's mathematically simpler to assume that antennas are infinitesimally thin, however, and usually this is close enough to true that it makes a reasonable ...
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2 votes

Should I chose a vertical or a horizontal HF antenna?

There are useful tidbits in all the answers so far. Here are a couple more. Not every ham has the good fortune to have conveniently spaced tall trees to hang horizontal antennas from. On 80 meters ...
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2 votes

Magnetic loop antenna: vertical vs horizontal

A small horizontal loop will have two sharp nulls: one pointing straight up and one pointing straight down. That may: Help reduce losses in the soil directly beneath it Reduce the NVIS radiation ...
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  • 7,495
2 votes

Variable polarization Yagi using two antennas on the same boom, joined together with variable feedpoint phase?

You should be able to use a traditional offset mount: The counterweight balances the weight and the wind-generated torque of the yagi. If you want to use a different offset for either side, use ...
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  • 7,685
2 votes

Magnetic loop antenna: vertical vs horizontal

There is no issue with a horizontal small loop per se. In fact, if you want a horizontally polarized antenna with equal gain in the horizontal plane, a horizontal small loop is a great way to do it. ...
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2 votes
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What are the properties of the radiation of a magnetron?

Paraphrasing the Wikipedia entry for the magnetron, we learn that, ... a stream of electrons passes by the openings to metal cavity resonators and causes microwaves to oscillate within, similar to ...
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  • 7,685
2 votes

What are the properties of the radiation of a magnetron?

I once wondered if a microwave oven magnetron might make a good transmitter, for CW for EME. I took a spectrum analyser and antenna to the kitchen and microwaved a glass of water, and I saw... The ...
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  • 7,817
2 votes

2 Meter horizontal or vertical dipole polarization?

I've always heard (but am unable offhand to quote authoritative research or provide an explanation of why this is so) that an advantage of horizontal for weak signal work is that a lot of man-made ...
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2 votes

Receiving the ISS SSTV: dipole antenna configuration and orientation

The ionosphere conversion to circular is not particularly good - e.g. see cv.nrao.edu/~demerson/ionosphere/ionopol.html. This means that the circular polarization is very variable (ratio of major:...
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  • 141
2 votes

Which way is a yagi polarized?

For what band? If you are looking to DX on HF, then horizontal is the way to go, because as AG5CI said, polarization doesn't make much difference after the first atmospheric refraction. I regularly ...
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1 vote

How Does the Propagation of H-pol E-M Fields Compare to That of V-pol E-M Fields (other things equal)?

As clearly shown in the graphic clip first below, h-pol e-m waves radiated at low elevation angles tend to be canceled by their reflections from the Earth near the antenna site. Note the last sentence ...
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  • 2,872

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