Antenna polarization when dealing with satellite communications
up vote
2
down vote
favorite
It's easy to understand, conceptually anyway, the difference between a horizontally polarized antenna and a vertically polarized one, when referenced to ground. However, when they are pointed nearly straight up at a satellite that reference is effectively lost. Yet communications with satellites require different polarizations. How does that work?
antenna satellites polarization
asked 4 hours ago
mike65535
4951316
add a comment |
up vote
2
down vote
favorite
It's easy to understand, conceptually anyway, the difference between a horizontally polarized antenna and a vertically polarized one, when referenced to ground. However, when they are pointed nearly straight up at a satellite that reference is effectively lost. Yet communications with satellites require different polarizations. How does that work?
antenna satellites polarization
asked 4 hours ago
mike65535
4951316
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
It's easy to understand, conceptually anyway, the difference between a horizontally polarized antenna and a vertically polarized one, when referenced to ground. However, when they are pointed nearly straight up at a satellite that reference is effectively lost. Yet communications with satellites require different polarizations. How does that work?
antenna satellites polarization
asked 4 hours ago
mike65535
4951316
It's easy to understand, conceptually anyway, the difference between a horizontally polarized antenna and a vertically polarized one, when referenced to ground. However, when they are pointed nearly straight up at a satellite that reference is effectively lost. Yet communications with satellites require different polarizations. How does that work?
antenna satellites polarization
antenna satellites polarization
asked 4 hours ago
mike65535
4951316
asked 4 hours ago
mike65535
4951316
asked 4 hours ago
mike65535
4951316
asked 4 hours ago
mike65535
4951316
asked 4 hours ago
mike65535
4951316
4951316
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
up vote
3
down vote
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
polarization of the EM wave.The geographic reference of the satellite polarization changes for
non-stationary satellite as it traverses its path above the earth-bound point of observation.
Either of these conditions can introduce significant antenna system losses when linear polarization is involved.
A circularly polarized EM (electro-magnetic) wave refers to a wave that rotates between horizontal and vertically polarization and all planes in between. The rotation cycle repeats once per wavelength. When viewing the wave in the direction of travel, a clockwise rotation is considered right hand circular (RHC) polarization while a counter (anti) clockwise rotation is considered left hand circular (LHC) polarization.
Amateurs often use cross polarized linear yagi antennas for circularly polarized satellite communications. Technically these produce an elliptical polarization. With a simple control of the phasing network, a near RHC or LHC polarization can be achieved.
The loss between antennas of mismatch polarization when at least one involves circular polarization is typically limited to 3 dB. This is contrasted to the loss between a worst case horizontal and vertical polarization that can incur an ~20 dB loss.
answered 1 hour ago
Glenn W9IQ
13.7k1742
add a comment |
up vote
2
down vote
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/vertical) for that exact reason; that's why when you open e.g. sat-TV feedhorns, you'll often find "snail"-shaped structures inside.
With clockwise and counterclockwise, you don't need absolute orientation; what's important is the same "rotational direction", if you will.
answered 4 hours ago
Marcus Müller
7,144830
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ifUsing("editor", function () {
return StackExchange.using("schematics", function () {
StackExchange.schematics.init();
});
}, "cicuitlab");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "520"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fham.stackexchange.com%2fquestions%2f12414%2fantenna-polarization-when-dealing-with-satellite-communications%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
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
polarization of the EM wave.The geographic reference of the satellite polarization changes for
non-stationary satellite as it traverses its path above the earth-bound point of observation.
Either of these conditions can introduce significant antenna system losses when linear polarization is involved.
A circularly polarized EM (electro-magnetic) wave refers to a wave that rotates between horizontal and vertically polarization and all planes in between. The rotation cycle repeats once per wavelength. When viewing the wave in the direction of travel, a clockwise rotation is considered right hand circular (RHC) polarization while a counter (anti) clockwise rotation is considered left hand circular (LHC) polarization.
Amateurs often use cross polarized linear yagi antennas for circularly polarized satellite communications. Technically these produce an elliptical polarization. With a simple control of the phasing network, a near RHC or LHC polarization can be achieved.
The loss between antennas of mismatch polarization when at least one involves circular polarization is typically limited to 3 dB. This is contrasted to the loss between a worst case horizontal and vertical polarization that can incur an ~20 dB loss.
answered 1 hour ago
Glenn W9IQ
13.7k1742
add a comment |
up vote
3
down vote
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
polarization of the EM wave.The geographic reference of the satellite polarization changes for
non-stationary satellite as it traverses its path above the earth-bound point of observation.
Either of these conditions can introduce significant antenna system losses when linear polarization is involved.
A circularly polarized EM (electro-magnetic) wave refers to a wave that rotates between horizontal and vertically polarization and all planes in between. The rotation cycle repeats once per wavelength. When viewing the wave in the direction of travel, a clockwise rotation is considered right hand circular (RHC) polarization while a counter (anti) clockwise rotation is considered left hand circular (LHC) polarization.
Amateurs often use cross polarized linear yagi antennas for circularly polarized satellite communications. Technically these produce an elliptical polarization. With a simple control of the phasing network, a near RHC or LHC polarization can be achieved.
The loss between antennas of mismatch polarization when at least one involves circular polarization is typically limited to 3 dB. This is contrasted to the loss between a worst case horizontal and vertical polarization that can incur an ~20 dB loss.
answered 1 hour ago
Glenn W9IQ
13.7k1742
add a comment |
up vote
3
down vote
up vote
3
down vote
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
polarization of the EM wave.The geographic reference of the satellite polarization changes for
non-stationary satellite as it traverses its path above the earth-bound point of observation.
Either of these conditions can introduce significant antenna system losses when linear polarization is involved.
A circularly polarized EM (electro-magnetic) wave refers to a wave that rotates between horizontal and vertically polarization and all planes in between. The rotation cycle repeats once per wavelength. When viewing the wave in the direction of travel, a clockwise rotation is considered right hand circular (RHC) polarization while a counter (anti) clockwise rotation is considered left hand circular (LHC) polarization.
Amateurs often use cross polarized linear yagi antennas for circularly polarized satellite communications. Technically these produce an elliptical polarization. With a simple control of the phasing network, a near RHC or LHC polarization can be achieved.
The loss between antennas of mismatch polarization when at least one involves circular polarization is typically limited to 3 dB. This is contrasted to the loss between a worst case horizontal and vertical polarization that can incur an ~20 dB loss.
answered 1 hour ago
Glenn W9IQ
13.7k1742
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
polarization of the EM wave.The geographic reference of the satellite polarization changes for
non-stationary satellite as it traverses its path above the earth-bound point of observation.
Either of these conditions can introduce significant antenna system losses when linear polarization is involved.
A circularly polarized EM (electro-magnetic) wave refers to a wave that rotates between horizontal and vertically polarization and all planes in between. The rotation cycle repeats once per wavelength. When viewing the wave in the direction of travel, a clockwise rotation is considered right hand circular (RHC) polarization while a counter (anti) clockwise rotation is considered left hand circular (LHC) polarization.
Amateurs often use cross polarized linear yagi antennas for circularly polarized satellite communications. Technically these produce an elliptical polarization. With a simple control of the phasing network, a near RHC or LHC polarization can be achieved.
The loss between antennas of mismatch polarization when at least one involves circular polarization is typically limited to 3 dB. This is contrasted to the loss between a worst case horizontal and vertical polarization that can incur an ~20 dB loss.
answered 1 hour ago
Glenn W9IQ
13.7k1742
edited 1 hour ago
answered 1 hour ago
Glenn W9IQ
13.7k1742
answered 1 hour ago
Glenn W9IQ
13.7k1742
answered 1 hour ago
Glenn W9IQ
13.7k1742
13.7k1742
add a comment |
add a comment |
up vote
2
down vote
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/vertical) for that exact reason; that's why when you open e.g. sat-TV feedhorns, you'll often find "snail"-shaped structures inside.
With clockwise and counterclockwise, you don't need absolute orientation; what's important is the same "rotational direction", if you will.
answered 4 hours ago
Marcus Müller
7,144830
add a comment |
up vote
2
down vote
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/vertical) for that exact reason; that's why when you open e.g. sat-TV feedhorns, you'll often find "snail"-shaped structures inside.
With clockwise and counterclockwise, you don't need absolute orientation; what's important is the same "rotational direction", if you will.
answered 4 hours ago
Marcus Müller
7,144830
add a comment |
up vote
2
down vote
up vote
2
down vote
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/vertical) for that exact reason; that's why when you open e.g. sat-TV feedhorns, you'll often find "snail"-shaped structures inside.
With clockwise and counterclockwise, you don't need absolute orientation; what's important is the same "rotational direction", if you will.
answered 4 hours ago
Marcus Müller
7,144830
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/vertical) for that exact reason; that's why when you open e.g. sat-TV feedhorns, you'll often find "snail"-shaped structures inside.
With clockwise and counterclockwise, you don't need absolute orientation; what's important is the same "rotational direction", if you will.
answered 4 hours ago
Marcus Müller
7,144830
answered 4 hours ago
Marcus Müller
7,144830
answered 4 hours ago
Marcus Müller
7,144830
answered 4 hours ago
Marcus Müller
7,144830
7,144830
add a comment |
add a comment |
Thanks for contributing an answer to Amateur Radio Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fham.stackexchange.com%2fquestions%2f12414%2fantenna-polarization-when-dealing-with-satellite-communications%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
