Questions tagged [satellites]

Amateur radio satellites refer to any artificial object in Earth orbit that are useful for amateur radio purposes.

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23 views

Can I use a DireWolf based digipeater to work the ISS digipeater?

I've recently become interested in ham radio, particularly AX.25/FX.25 packet radio. I ordered the basic setup (RPI, DireWolf, BaoFeng, a sound card, and some cables) and I was wondering with this ...
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Any tool for finding satellite passes that overlap *two* given locations?

gpredict is nice. Well, it's OK, to find the next passes for a set of satellites with sufficient elevation for one location. What I want is something where I can put in two coordinates, and get out ...
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75 views

what is the baseband for CATV?

I was reading on wikipedia this: the subscriber's television or a set-top box provided by the cable company translates the desired channel back to its original frequency (baseband) But when I ...
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112 views

How much of the 136 - 174 mhz spectrum is actually in use?

I know that 144-148 and 156-157 mhz ranges are in use, and various fire/ems/police, but outside of that, I see a lot of earth-to-space, weather stuff and space research allotments (talking about ...
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168 views

Receiving the ISS SSTV: dipole antenna configuration and orientation

In short I am trying to receive SSTV Images from the ISS (145.8Mhz) and I all have is a simple "bunny ears" dipole antenna. In what configuration (straight, vee shaped, upside down vee, ...) ...
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118 views

Calculating satellite passes without an internet tracker?

Situation: You want to know when a satellite will pass in order to receive an image transmission or to work an amateur satellite. However, you cannot access internet for whatever reason, and ...
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39 views

How to decide between Dipole and Monopole antenna for Cubesat Uplink (433 MHz)? [duplicate]

We are currently deciding between a dipole and a monopole for uplink (435MHz) , while the monopole is easier to feed, we are unsure of how effectively we'll be able to implement the ground plane, ...
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768 views

Why does Free space have the highest loss compared to other losses like atmospheric loss, feeder loss etc?

In a communication Satellite system, there are losses that occur when the signal is received at the antenna and then passed through a communication link to the output stage which could be the receiver....
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77 views

Could not observe the Meteor M2 even though I scanned the sky at the time it passes with a high elevation degree (77). What might have happened?

I am currently trying to observe and obtain data from the meteorological satellites. I have constructed a V-dipole specifically for the 137 MHz and was able to observe the NOAA 15, NOAA 18, and NOAA ...
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42 views

How does one log a QSO via a cross-band repeater?

When working through a cross band repeater, either the two sides are using different bands or both sides are using two bands at once. At the same time, most if not all logging software (as well as ...
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124 views

Double Cross Dipole antenna for 437 MHz don't tune

I'm building a Double Cross Dipole antenna for 437 MHz to be used with a SDR receiver for CW cubesat. The idea is to follow this "classic" paper from Gerald Martes, KD6JDJ. I tuned every single dipole ...
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186 views

Ham Radio and Space Communications

I hear a lot of people talking about getting in contact with space with their ham radio. What do you hear? Do you talk to astronauts? Or: Is it just an expression?
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Circular polarized antenna feed changes as I rotate it?

I had a 100cm prime focus dish laying around and I thought of making a circularly polarized feed for it, since it seemed pretty straightforward from what I've been reading. Helical feeds are supposed ...
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146 views

APT/LRPT images geotagging

I want to extend functionality of some open-source programs which decode APT and LRPT images (wxapt and glrpt). More specifically I want to add possibility to overlay geographical data such as land ...
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1answer
58 views

2 meter and 70cm OSCAR expected signal attenuation by topocentric elevation angle, chart?

On average, is there a chart, or formula, which shows an expected signal attenuation due to the elevation angle to the satellite's position? I understand that range (distance) is also going to affect ...
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137 views

Working satellite on 2 meters, at what arc distance to sun (center) will noise floor be problematic to a disruption of a communication path?

Is there some simple utility, or published set of charts, or suite of formulae, where one can approach the situation by inputting a space weather summary, (sunspots, various indexes, etc), the receive ...
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111 views

Kenwood TH-D72A and AO-91/92

I got a Kenwood HT and using it with the Elk Antenna On the radio, there is Tone and I set it to 67 Hz. I wasn’t able to break thru to the satellite and had it in Full Duplex mode. I can hear ...
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102 views

Gain of Yagi turnstile?

I am currently working on a system to communicate with amateur CubeSats. I have decided to use the turnstile crossed-dipole style yagi because it is relatively easy to construct and uses circular ...
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102 views

Is it possible to receive weather satellites with a ham radio rig? (Icom 910)

I would be interested in receiving weather satellites (NOAA and Meteor) with my Icom 910. It has very good filters and could be a better solution than a simple SDR. However, its manual specifies that ...
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80 views

Are there any satellite email reflectors?

I'm just getting started using amateur satellites and would like to subscribe to an email reflector, but I can't find one. Is there anything out there?
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What value goes in the AX.25 PID field if the Layer 3 protocol is not defined in the standard?

I am working on space-ground networking for a Cube Satellite, and one of our candidate Layer 2 protocols is AX.25. We haven't settled on a physical layer, but it's likely to be some form of quadrature-...
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1answer
228 views

How do amateur satellites stay consistently in the amateur-sat bands acoss the globe?

I understand that my local laws may differ but amateur radio satellites, by their very nature, orbit the earth going over several legal jurisdictions. Are satellite bands the same internationally? If ...
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508 views

How do I listen to the amateur radio satellites?

I'm new to amateur radio, and I would like to listen to those satellites in the orbit. Where do I start? What types of amateur radio satellites exist?
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267 views

Using Satnogs' *.ogg files in GNU Radio flowgraphs

I want to use the *.ogg files available in Satnogs' database to test demodulation software for several satellites (using gnuradio). Can I use the ogg file source (available in gr-satnogs module) and ...
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Noise Floor when receiving Es'hail 2

I'm currently trying to receive the Es'hail 2 satellite using a standard TV LNB, 60cm dish and RTL-SDR. My dish is slightly offset by 2 degrees, and my SNR is only about 15dB unfortunately. My main ...
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116 views

How can I improve my Es'Hail 2 reception?

I'm using an RTL-SDR to receive Es'Hail 2. My chain is as follows in order: 60 cm TV Satellite dish pointing 2 degrees off Es'Hail 2 Universal LNB (from TV company, not really a stable frequency). ...
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2k views

Why would you need a signal generator to receive early satellite transmissions?

I recently watched, on You Tube, a NOVA program about the British school masters and students who were the first to publish the news that the Soviets had started launching satellites from a new launch ...
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538 views

Who funds amateur radio satellites?

I am currently studying for my Technician Exam and I am amazed at the sheer number of amateur radio satellites in orbit. Knowing how expensive it is to launch something into space, and assuming there ...
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42 views

Any reception reports from ExseedSAT1 yet?

My answer to the question Where can I find the TLE of ExseedSat 1, India's first ever private LEO satellite? is currently that while 60+ objects are being tracked from this mutli-payload launch, ...
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2k views

Antenna polarization when dealing with satellite communications

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 ...
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1answer
120 views

Help understanding this tweet about receiving images from satellite behind the Moon

This GBTimes article A tiny Chinese satellite is orbiting the Moon and allowing radio amateurs to download images links to this tweet which shows a high gain UHF? antenna pointed at the Moon, and that'...
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Can I build a radio telescope out of a parabolic TV satellite dish?

I have the possibility to buy a very inexpensive 2.4m parabolic satellite dish and I would like to build a radio telescope from it. Originally this dish was designed to be a satellite TV antenna. ...
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268 views

Doppler shift compensation without using predictive modelling

Doppler shift mitigation has been studied extensively in the literature. In my implementations of satellite receivers (using GNU Radio), I use predicted Doppler shift from a software (GPredict) to ...
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142 views

What wireless communication technologies can travel long distances with a high bandwidth?

I couldn’t find a better place to ask this question, so I have asked it here. I am looking to transmit and receive internet connectivity wirelessly over a distance of 6 miles (9.7 km) with a minimum ...
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682 views

What is the turn spacing on a Helix Antenna?

I want to do some satellite communication so I thought why not build my own helix antenna. I found this page: Helix antenna design and construction details The most things are clear except for the ...
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2answers
182 views

I would like to listen to a red roadster in space

I have been listening for signals (any) of the Space-X Falcon Heavy. Just out of curiosity. And I am wondering if anyone has received any. According to the Falcon-9 User Guide table 4.6 looks like ...
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234 views

Who regulates ham radio satellites?

I have doubts regarding the control authority of the amateur radio satellites, because recently we have drastic changes to Internet control by FCC as the next major decentralized communication system ...
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227 views

What happened to AMSAT-Phase 3E?

The web pages related to the unlaunched satellite were last updated in 2007, so I wonder - where is it now? Is it going to be launched someday?
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332 views

Would the antenna described work?

For reception of amateur radio satellites, turnstile antennas (consisting of two crossed dipoles fed out-of-phase) are often used. I've recently had an idea - what if two half-wavelength dipoles are ...
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1k views

How to transmit images and video through a hurricane?

Background You're in the path of a hurricane, and the eye just passed over your head. There is no electricity (apart from your own generator or battery), there is no mobile network and there is ...
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229 views

Could UHF Earth-Satellite-Earth bouncing of signals off of this large metallized foil satellite be feasible?

The July 14, 2017 NASA Spaceflight article Soyuz 2-1A launches with Kanopus-V-IK and over 70 satellites says: Mayak is a three-unit CubeSat which was built by Tvoii Sektor Kosmosa – or “Your Sector ...
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2k views

doppler LEO satellite

I am trying to model Doppler shift of LEO satellite, From my research so far I have come across the following formula: \begin{equation} \frac{f_r}{f_s}=\frac{1-\frac{u}{c}cos\theta}{\sqrt{1-\frac{u^2}...
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APRS digi path for ISS digipeater?

So when I try to work the ISS digipeater, what should I set the digi path to be? My setup is a 5 W HT with a 2 m yagi connected to my phone with APRSDroid. I've tried the past few nights with ...
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114 views

Is there somewhere I can get a database of satellite catalog IDs and their friendly names?

I'm working on a program for ham radio that involves displaying satellites. I'm currently using the Space-track.org database, but the problem with it is that it will give "Saudisat 1C" rather than SO-...
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591 views

Autoranging problem for AX5043 transceiver (437.025MHz)

I am trying to configure AX5043 transceiver(ONSEMI) for PSK modulation and system parameters are as follows: ...
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1answer
149 views

Can one modify footprints in Gpredict?

I have created a TLE to represent my theoretical satellite whose orbit I wish to plot using Gpredict. I have managed to load it all up onto the program and it is looking good, but one thing remains - ...
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cubesat turnstile antenna material selection

My cubesat team is working on our design for rolled whip antennas to deploy in a UHF turnstile configuration based on this design: What I would like advice on is the material for the antennas ...
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671 views

How to bypass LNA for TX in UHF Antenna?

I want to work with amateur, low power, and/or pico satellites. I would like to use an Eggbeater or Turnstile antenna with my UHF 433 MHz radio, since those antennas are very cheap and easy to build ...
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209 views

SkyStar S2 has a mac address, for what? [closed]

Hy just a "stupid" question, I bought a technisat skystar s2 pci card. Can any body tell me why this thing has a mac address printed on it? ^^ And the mac address can even been looked up. (00-08-c9-xx-...
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183 views

What are the legal requirements for an amateur radio satellite?

Lets say I can throw a satellite into orbit (I've got a good arm). I'm amateur radio qualified so can I just set it up to transmit on an amateur band and start having fun? Is there anyone I have to ...