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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94 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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163 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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57 views

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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114 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
53 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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128 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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1answer
81 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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1answer
77 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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1answer
96 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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72 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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226 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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383 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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172 views

Using Satnogs' *.ogg files in GnuRadio 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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37 views

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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104 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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521 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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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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1k 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
115 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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3k views

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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254 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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140 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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1answer
564 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
170 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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4answers
226 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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209 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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299 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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2answers
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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200 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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1k 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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113 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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562 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
131 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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1k views

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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1answer
594 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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202 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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177 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 ...
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687 views

GFSK Demodulationsoftware

I need to demodulate and decode a signal.It is transmitted from a satellite using GFSK. The packets are based on AX.25. Could you recommend any out-of-the-box HAM software packages that could do ...
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950 views

AFSK and GMSK in ICOM IC910 H

I am a newbie in HAM.The transceiver I have in my lab is ICOM IC910 H. My goal is to use it to communicate with our cubesat which uses GMSK. According to the manual, on page 50, there are notes for ...
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107 views

ISS SSTV transmission times

Unfortunately, the ISS SSTV transmissions scheduled to the next weekend had to be canceled. Anyway, I'm planning to capture some images and have a doubt. I've been trying to find some answers, but no ...
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352 views

Weather Imaging with NOAA satellites - legal?

I would like to build an antenna for receiving NOAA weather satellites. They're receivable at around 137.5 Mhz. I'm a total new to amateur radio stuff. I know that it's not legal to communicate as ...
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1answer
104 views

FUNcube Dongle antenna specs

What are the specs of the FUNcube Dongle antenna? I mean, how to fully describe only the antenna?
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387 views

Replace directional antenna by fixed antenna

Given the following specs of a directional antenna: ...
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2answers
199 views

Ettus USRP1 (or B100) instead of Funcube Dongle

Is it possible to use an Ettus USRP1 (or B100) instead of Funcube Dongle to receive cubesat signals? The Ettus ones are more expensive.
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77 views

Directional antenna for FUNcube reception

Will a directional antenna guarantee longer reception periods then a standard antenna? May I ask for the specs for one of this directional antennas to use with RTL-SDR?
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146 views

Track cubesat with webSDR, is is feasible?

WebSDR is a Software-Defined Radio receiver connected to the internet. Here is being said "OK for HF but no good for VHF / UHF". I was thinking to use it for cubesat reception but given that the ...
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175 views

Low cost satellite (cubesat) tracking station

To track and receive some data from satellites, or should I say cubesats - which are kind of popular these days, which is the minimum investment? What's cheapest/easiest satellite to begin with? ...