Questions tagged [antenna]

Questions about devices which collect and couple electromagnetic signals (communications, radar or other electromagnetic measurements) directly between free space, and conductors (e.g. waveguides or other transmission lines).

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781 views

Why were the antennas on the spherical surface of some early satellites spiral-shaped?

In the question What's the spiral pattern on this satellite? I show this image of a spiral-shaped pattern on the spherical surface of a (presumably) vintage satellite or model thereof. @OrganicMarble'...
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1answer
133 views

What's the largest area dish antenna sent beyond the Earth-Moon system?

In the same vein as the question What's the largest aperture telescope sent beyond the Earth-Moon system?, I'd like to ask, what's the largest area antenna dish sent beyond the Earth-Moon system? If ...
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How would the antenna on a spacecraft in GEO be provided an electrical ground?

I would like to understand better what specifications or guidelines address the electrical grounding/Earthing a parabolic reflector Antenna in GEO to minimize the potential difference with respect to ...
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What is the large circular device with a dozen concentric circles on Sentinel 3B?

The Spaceflight Now article Photos: Sentinel 3B satellite prepared for launch from Plesetsk Cosmodrome has of course lots of photos. One of them shows a dish antenna covered with shiny, metallized ...
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1answer
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How does Curiosity know how to point and move it's high gain antenna in real time?

The Curiosity rover has a compact X-band high-gain antenna (HGA) that allows for low data rate communication directly with Earth, but is used mostly for higher data rates to spacecraft orbiting Mars, ...
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199 views

The appearance of TESS' dish seems to be evolving, what will be the final configuration?

The question Why is TESS' high gain antenna made of undulating BLACK fabric rather than metal? has had three bounties, and is probably the recipient of this sites longest answer. My personal pet ...
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1answer
836 views

What is Canted Turnstile Antenna System? What it its Applications?

There are not many sources I can read to know about this kind of Antenna and its Applications
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1answer
884 views

How does SpaceX Falcon Heavy Starman live feed transmitter work?

I'm curious to find out answers to the following questions: Where is the antenna for the live feed transmitter of starman located in the payload? How is the transmitter being powered? Related to 2nd ...
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66 views

What is the Telescope Invariant Point?

I am working on an implementation of an SLR tool. At some points of the documentation of the CRD format the term telescope invariant point shows up. Apparently it's a point on an ILRS antenna system. ...
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How to design a ground antenna for sending & receiving from a satellite?

Let's suppose there is a wifi router or a cell phone or similar transmitter in an orbit of 3000 km. How could one make a dish antenna to connect and receive the signal from that wifi router or cell ...
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1answer
445 views

What were those motorized human-piloted platforms with helical antennas called (tracking launches)?

This interesting question got me started. I have these vignettes in my Apollo-era memory of antenna systems that tracked launches for telemetry. They had maybe four end-fire helical antennas pointing ...
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What is this spinning object seen on a spacecraft above the ISS?

In the YouTube Trailer for the PBS program A Year in Space at 00:56 a small spinning object can be seen, attached to a spacecraft well above the ISS. I think the ...
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How did this structure fit into the Shuttle and then expand to 28 meters?

In this answer I read about the Inflatable Antenna Experiment that flew with STS-77. According to this article: Packed into the Spartan, the IAE weighed only 132 pounds; on deployment (inflation), ...
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Calibration of Antennae in satellite and in ground station [closed]

How to orient the ground station antenna and that of the satellite just after the launch?
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Angular distance between two satellites given azimuth and elevation angles for each?

If the look angles for a pair of satellites are $Az_1, El_1$ and $Az_2, El_2$, what would be the angular separation between them? An associated problem is how do we determine whether and when the two ...
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1answer
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Will there be “Near Space” Ka-band allocations for TESS?

update: More information in Phys.org's news item TESS mission to discover new planets moves toward launch, including a video of the telescope array's final assembly. Also see GSFC's TESS page. The ...
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Why is TESS' high gain antenna made of undulating BLACK fabric rather than metal?

above: from Facebook, then annotated. There is an excellent review of the design of the TESS spacecraft in G. R. Richter et al. Journal of Astronomical Telescopes, ...
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What is the function of this (apparently) fixed dish on the ISS?

I saw this image in Popular Science, one of the example photos from the book by astronaut/photographer/astrophotographer(?) Donald Pettit. It's beautiful and impressive not only from a color/...
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1answer
189 views

What are these dishes looking at?

In this CSA video CSA Astronaut Chris Hadfield describes the attitude control of the ISS and its importance for things like communication with Earth. At 00:30 here ...
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1answer
443 views

How do commercial broadcast satellites in GEO produce such carefully shaped signal footprints?

SES-10 will be launched in a few days on Space-X's first commercial launch using a recycled rocket. Screenshots from the three links (Brazil, Central America, South America) on Satbeams page for SES-...
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1answer
554 views

How is GAIA's phased array configured, mechanically and electrically?

GAIA is an amazing pair of space telescopes that share a single Gigapixel CCD array, with a complex optical system capable of repeated, extremely precise position, brightness, parallax, proper motion, ...
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2k views

Why did Sputnik 1 have four antennas?

Sputnik was only launched a few hundred kilometers above Earth, and transmitted only a simple beeping signal. What was the purpose of having four antennas? Wouldn't one be powerful enough?
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328 views

Deep space craft antenna aiming

In order to aim an antenna at Earth, how do unmanned spacecraft find their own orientation (xyz position in space, what direction it is flying and which direction the antenna is pointing)? Are they ...
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When is a phased array antenna not a phased array?

This question is inspired by an answer to this question, where it is stated that: The real power of phased arrays is their ability to be steered electronically. This set me wondering about the ...
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974 views

Radiation pattern and signal strength of navigation satellite antennas

Where can I find the actual radiation pattern and signal strength of transmitting antennas used by GNSS navigation satellites/constellations (GPS, GLONASS, IRNSS, etc)?
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How are phased array antennas used in spaceflight? Benefits and limitations

It would seem to me that a phased array antenna would be great for spacecrafts since it removes the need to turn the entire spacecraft around in order to point the radio dish towards Earth. Many ...
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559 views

Can't we use laser transmitters instead of large radio dishes on deep space probes?

Isn't it possible to use a laser as an "antenna" that transmits data? This would save quite a lot of mass since you don't need a large dish. The only problem I can think of is how would you modulate ...
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What is the purpose of the rotating dish antenna on the ISS

I just saw some footage of the ISS in which a dish antenna could be seen, constantly rotating. The dish looked more-or-less parabolic, meaning that it is presumably sending/receiving along a fairly ...

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