Questions tagged [radio-communication]

Using radio wavelengths to communicate between multiple spacecraft or between a spacecraft and the Earth.

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332 views

How did Argentina, Namibia, and Pakistan help China monitor and communicate with Chang'e 5?

At the end of The Hill's article Chinese official unveils future moon mission plans including possible lunar base it says: The most recent Chang'e 5 probe was assisted by the European Space Agency, ...
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Did New Horizons use its smaller medium-gain antenna for most/all downlinking of Pluto and Arrokoth flyby data?

Brian May's New Horizons video (below) was released at about the same time that the New Horizons spacecraft passed 2014 MU69 Arrokoth and includes a lot of technically meaningful graphics. One item ...
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Real time communications in space

Today we use audio and video communications (using UDP protocol) over IP networks (VoIP) for communicating (Skype, Whatsapp, FB messenger). This works fine on planet Earth (although there are various ...
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Is it possible for small satellites to orbit in MEO or GEO?

I am researching satellite technology, and in particular I am looking at the rise and implications of smallsat technology. As far as I know, there are currently no satellites beyond LEO that would be ...
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216 views

What is the lowest power signal that the DSN can detect?

It is said that the Deep Space Network can detect low-power signals sent from Voyager in the range of 10^-16 W. I can't seem to find any sources that indicate what the minimum power requirement of a ...
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Function and nature of the RHC/LCH pair of cables to New Horizons's dish antenna secondary mirror?

Spaceflight 101's New Horizons Spacecraft Overview is full of interesting information and shows this RF Comm System Block Diagram. The thin (red) lines to the dish antenna area are coaxial cables and ...
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2k views

What is the advantage of QPSK over FSK or ASK for satellite data transmission?

I am wondering what are the big advantages and disadvantages using QPSK, FSK,and ASK in satellite communication. In our project, which is in phase 3, are we supposed to work with QPSK modulation for ...
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What is the bandwidth (in hertz) of the Voyager 2 radio receiver?

Does anybody know the bandwidth of the Voyager 2 radio receiver's front-end? I know that the current data rate of the receiver is of order tens of bits per second, and I have one estimate of 18 Hz. ...
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1answer
478 views

How does SpaceX transmit the video feed from the first and second stage cameras back to Earth?

There appear to be at least 1 reasonably high-res (500+ px vertical res) live video stream being transmitted from both the SpaceX F9 first and upper stages all the way up into LEO throughout their ...
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1answer
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Possible interference in RF spectrum due to space-based internet

Multiple Commercial Operators plan to use satellite megaconstellations for providing internet coverage in near future. Is there a possibility of interference between RF spectrum already in use for ...
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Power and frequency units used in Deep Space Network XML data?

NASA's Deep Space Network activity can be viewed conveniently at https://eyes.nasa.gov/dsn/dsn.html but if you would like data in a more raw XML form, it can be accessed as described in this answer ...
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UHF transceiver for cubesats network

I already asked things related to this topic. But this time I will try to divide it by points to make it more understandable. Features of my cubesats: Would have 8 cubesats 3U in Earth's orbit The ...
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1answer
150 views

How does an onboard atomic clock help interplanetary navigation?

On 2019 June 22, JPL will launch and test the accuracy of an onboard atomic clock. Its FAQ says that it will improve interplanetary navigation because for the ship to determine its position, instead ...
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What are the trade-offs to use a radio relay orbiter also as a radar science instrument?

Any landed mission could benefit from having an orbiting radio relay satellite to help enhance its data rate to Earth. For polar landers on for example the Moon or Mercury it would be a necessity. For ...
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787 views

Is there really a radio on Elon Musk's solar-orbiting Tesla Roadster? Can we communicate with it? [closed]

Various media have reported that there is a radio on Elon Musk's Tesla Roadster, now in orbit around the Sun, and that this radio is playing music (for example: BBC reporting that David Bowie's ...
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What kind of signal Voyager 1 is sending to us?

I was reading on wiki about Voyager 1 mission and I found very interesting! One thing I did not manage to find: what is the signal Voyager 1 is sending to us? Is it simply a sinewave or something more ...
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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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Is or was STARGATE really being used for SpaceX launches at Boca Chica or otherwise?

The 2015 answer to For SpaceX's Texas launch site, what kind of range radar/tracking will they have? links to The Spacecraft Tracking and Astronomical Research into Giga-hertz Astrophysical Transient ...
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What's the most intense beam ever sent from Earth?

By a freak coincidence sensors on a passing alien ship a hundred light years away had picked up a faint artificial blip from Earth, thereby discovering our inhabited planet. But which blip was it? ...
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Does Russian mission control still use the callsign “Zarya”, and how did that not conflict with the ISS module?

The Wikipedia page for the Salyut space station claims Initially, the space stations were to be named Zarya, the Russian word for 'Dawn'. However, as the launch of the first station in the ...
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Satellite Megaconstellations RF Spectrum usage for free(?)

As per my understanding, for terrestrial usage RF spectrum is auctioned by the governments before telecom operators can avail it for commercial purpose. Seems like a logical way to utilise limited ...
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431 views

why do astronauts in the ISS still use wired microphones?

While I watched the DM-1 hatch opening, I noticed that astronauts use the wired microphone to talk to Huston. It was particularly strange seeing that even because during hatch opening, they were ...
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Understanding shape of DSN's 'kinky uplink protocol' keeping frequency in coherent transponder's optimum bandpass?

This tweet by deep space SDR enthusiast and amateur radio operator Edgar Kaiser @df2mz shows a squiggly tone from MRO. Mars Reconnaiscance Orbiter (MRO) X-band downlink. The signal shows this ...
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Satellite Intra link [closed]

I read there are sometimes intra-satellite links. Is it already used or just a project in the future ? How is is used and why ? and for what services ? thanks david thanks for interesting answers. ...
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331 views

How do satellites communicate with a relay satellite?

Although the exact usage of the system is classified, NASA has a system called TDRS which is used by other government agencies for relaying data to ground stations. To maintain communications with a ...
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Was it a “Soviet military satellite not in any of the catalogs?”

I can't connect to the Tass news item directly http://tass.com/science/896683 but on a SETI page an item dated August 31, 2016 says: An article that quotes the Russian news agency TASS is ...
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Why are space probes / satellites data rates so low? [duplicate]

The New Horizon's data transfer rate is only about 2kbps right now. At its peak the rate was 38kbps. Why is this transfer rate so slow? Is this due to using radio waves, limitations in the data relay, ...
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Why are minimum three artificial satellites required for radio-communication all around the Earth?

Artificial satellites orbiting the Earth have important applications for radio-communication around it. To avoid the blockage of radio-communication around the Earth, multiple satellites can be ...
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1answer
330 views

Characteristics of the modern satelite radio transmitters

I'm trying to find some data concerning current Earth-satellite radio communication systems, namely general characteristics of the equipment currently used on satellites. Specifically, I'm interested ...
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Are these good specifications for a X-Band High Gain Antenna?

Currently, I have that for a X-Band High Gain Antenna functioning at 8Ghz, diameter of 3 meters, and a power transmission of 13.1dBW(20Watts) at a distance of about 8.5AU has a Gain of 52.44dBi, free ...
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169 views

Does the Juno spacecraft have an “open signal, by design”?

The click-bate title'd Space News article China quietly used NASA’s Jupiter probe to test its deep space network contains the quoted material below. Everybody listens to everybody else's spacecraft's ...
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What is considered a good SNR for satellites?

When performing a link budget for satellite communications, a key component is defining an acceptable signal-to-noise-ratio in order to obtain the necessary bit-rate. How does one determine what the ...
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649 views

What is the highest non-optical frequency used or tested for use in deep space communication?

For dish antennas used to transmit a signal over large distances, the on-axis gain scales as $D^2/ \lambda^2$ or $D^2 f^2 / c^2$ where $\lambda$ and $f$ are the wavelength or frequency and $c$ is the ...
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What did Sputnik-1 sound like? Did it use multiple tones?

Radio transmissions from Sputnik-1 could be heard on short wave radios around the world. Questions: A carrier signal only would not be particularly audible to an AM radio listener, was it modulated ...
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135 views

IRIS Transceiver for LEO Missions?

My professor really wants to know if the IRIS transceiver, which flew on MarCo, will be used in LEO. In fact so much that he doesn't accept "no" for an answer. I have searched for an example but found ...
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207 views

If a MarCO-type CubeSat were in orbit around Bennu, what kind of power would it need to communicate with the Deep Space Network?

This is a follow-up question to: What is the lowest power signal that the DSN can detect? Essentially, I have determined that the asteroid Bennu (ranging from 25 to 350 million kilometers from Earth) ...
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1answer
61 views

How will “InSight's onboard communications gear perform a radio-science experiment to shed further light on Mars' innards?” (Space.com)

The Space.com article How NASA Mars Lander's 'Steampunk' Claw Will Work (Video) says: InSight's mission aims to provide a detailed look at Mars' interior structure and composition. The lander ...
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Interactions between rocket exhaust and radio communications?

Rocket exhaust is bright in visible light, we can still see through it but when there's hot, glowing soot it's so bright that we think it's opaque, but it's not. See answers to How does the camera ...
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Data Rates and Radios with Satellites [closed]

I am new to using radios and was wondering why do data rates matter when you use a radio to pull info from somewhere else. Also what does it mean when a satellite sends a wide band signal. Thank you ...
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1answer
123 views

Which is stronger per Hz, radio signals from a Mars spacecraft, or Mars' blackbody radiation?

It just occurred to me that while Mars is cold from a human's perspective, from a radio engineer's perspective it's still kind-of hot. When even the largest DSN antennas are pointed at Mars to ...
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1answer
303 views

Juno RF power output

What is the RF Power Output from Juno into its Parabolic dish, and the RF radiated out from the dish and the eventual power received say at the dish in Canberra which obviously then would need to be ...
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1answer
229 views

Impact of having two antennas on link budget calculations

I'm working on link budget of a cubesat mission that needs to have two dipole antennas that are perpendicular to each other. I want to know if having two antennas affect the link budget? losses, and ...
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What kind of transmitters and antennas do the Lightsail-2 ground stations use?

The cubesat Lightsail-2 has been deployed and has communicated with ground stations. See The Planetary Society's LightSail 2 Healthy as Mission Team Continues Spacecraft Checkouts, where it says: ...
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How does this antenna work, with both a feed horn and hyperbolic secondary in front of the dish?

Scrolling through the Roscosmos twitter feed I saw this image of a dish antenna in a recent tweet. Google translate shows that the post says: Новый измерительный пункт будет построен на Сахалине для ...
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How long did the plasma blackouts of Perseverance's signals to MRO and direct-to-Earth last during its seven minutes of terror?

Congratulations to NASA JPL and the Perseverance Team and everyone else who participated and contributed in some way! Watching the live feed of the EDL seven minutes of terror I heard there was a ...
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Satellite Launch Aprroval: what is the role of ITU, FCC, and other international standards / regulators?

Seeking confirmation for the following assumption: Satellites used for non-communication applications (military surveillance, weather monitoring etc.) are launched without specific prior approval from ...
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What's the “thump” I hear listening to Apollo 11 playback?

I've been listening to live playback of the Apollo 11 mission at https://apolloinrealtime.org/11/ Besides the expected static and hums, from time-to-time I hear a "thump", sometimes one, sometimes ...
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Can I transmit signals from a wristwatch to geostationary orbit?

In comments below this answer to the question Which satellites can hear emergency signals from Scott Kelley's watch? we are (or at least I am) trying to figure out definitively if a wristwatch can ...
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How to build an antenna to receive VHF or UHF? [closed]

I am trying to build a cubesat using a Raspberry Pi. I am now figuring out how to communicate with it. As far as I know, I understand I will have to use VHF or UHF to do so. How do I decide on the ...
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Which satellites can hear emergency signals from Scott Kelley's watch?

In this July 2018 tweet by Cdr. Scott Kelley, with the north face of Mt. Everest over his shoulder, he mentions his "Emergency" watch. I've searched and then found the Hodinkee.com article ...