Category Archives: Space Radio

DIY space, Education, Space Radio

Weather satellite image reception using a low cost SDR based system

In the HobbySpace Radio section I describe a weather satellite image receiving station I set up many years ago consisting of a simple antenna, a PC controllable receiver and a PC with a sound card. When a satellite passed overhead, and the receiver was set to the proper frequency band, the sound card would digitize the receiver output  and programs running on the PC would convert this data into an image. (I also had a program running to track satellites to know when a low earth orbit weathersat would be in range.)

setup3NOAA14-20-02-2000_col_mdA LEO weather satellite image (Colors assigned to gray scale values.)

That was a fairly inexpensive station but now there are even cheaper ways to do weathersat imaging at home.

A few times I’ve mentioned the FUNcube Dongle project that was created as part of the UK FUNcube satellite project to get students and the general public involved in receiving signals from that satellite.  The FUNcube Dongle is based on Software-defined radio (SDR).

SDR uses the power of modern microprocessors to allow a software program to replace many of the tasks previously  done in a hardware receiver to isolate and process and demodulate a signal of interest in a particular frequency band. The software  works on data obtained from digitizing the raw electromagnetic  wave patterns from an antenna.

Ideally an antenna output would straight into an analog to digital converter (ADC) in the PC, such as that available  in the sound card, and the SDR program would work on  the ADC output. However, that is not practical with real world noisy, weak signals. So some interface hardware  is still needed. This can be provided by a “dongle”  USB device that might include a low noise amplifier, a  tuner to obain signals in a given frequency range,  a ADC, plus a processor to control all this and talk with the PC. The output of the dongle is then used by the SDR program running on the PC.

FUNcubeDongle

From Introduction to the FUNcube Dongle (pdf)

So a system to receive low earth orbit weather satellite images can now be as simple as an antenna connected to a small low cost dongle plugged into the USB port of a computer running the SDR program. which analyzes the digitized signal in the frequency range selected  by the user. For satellite imaging, there would, as with the standard hardware tuner case, be another program to decode the signal into a weather image.

Besides the FUNcube Dongle, the company NooElec offers kits with an antenna and a SDR dongle. (Available at Amazon: Terratec DVB-T USB Receiver & Low-Cost Software Defined Radio (SDR).

A free program to operate such systems is available at SDR-RADIO.com.  Here is a tutorial for using it to pick up weather satellite images: Software Defined Radio for Mariners: Weather Satellites.

Find more SDR resources here.

The signal environment where you are located, say in the middle of a city with high buildings, could be very  poor for satellite reception. In that case, you can still do SDR satellite reception by getting the signal data from other locations via the web. See SDRSPACE.com  for details.

Amateur/Student Satellite, Space Radio

AMSAT & ISS amateur radio news

Go to AMSAT News for the latest headlines about developments in amateur and student satellites and for updates about amateur radio on the ISS.
ANS 244 Weekly AMSAT Bulletin – August 31, 2013:
* AMSAT-NA Board of Directors Ballots Due By September 15th
* FUNcube-1 Launch Date Announced
* A Ham Radio AX.25 Open Source Soundcard Modem
* Ham Radio Satellites at Tokyo Ham Fair
* SpaceUp India 2012 Videos Now Posted
* CAMSAT (AMSAT China) to host “a big DX party”
* ARISS News
* Satellite Shorts From All Over

 

Satellite Watching, Space participation, Space Radio

The FUNcube Dongle SDR for satellite reception

I’ve posted about the FUNcube Dongle before but it’s worth a repeat. This small device plugs into a USB port and when combined with a program like  SDR# “A Software Defined Radio in C#” your computer becomes a fully functional radio tuner. With a proper antenna and preamplifier you can pick up satellite transmissions such as weather satellite images.

The FUNcube Dongle came out of a AMSAT UK project to allow students and hobbyists an easy system to use to receive signals from the FUNcube UK Amateur Radio Educational Satellite, which is expected to be launched this fall.

More at

See also the See HobbySpace Space Radio section and the HobbySpace Weather Satellite Station.

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Satellite Watching, Space Radio, SpaceCasts

Tracking satellites and other space objects with RF signal reflections

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Mike Coletta is a ham radio hobbyist who uses RF signals emitted by the Air Force Space Surveillance System (AFSSS), also known as the space fence,  “to track near-Earth objects like satellites and space debris”: Tracking the International Space Station with metal coat hangers – gigaom.com

Coletta tracks all kind of near-Earth objects: the International Space Station, satellites, meteors. Signals picked up by the antenna, which is made of a 10-foot wooden board and metal coat hangers, are converted into tones that differ depending on the direction and location of an object. The tones, layered over a background of heavy static, grown louder and then softer as the object passes by, like a train traveling toward you and then barreling away. Listen to the sound of the ISS here.

This space fence is described in this recent article:  Air Force Space Command to discontinue space surveillance system – U.S. Air Force

The AFSSS, which has been operational since 1961, is just one part of AFSPC’s global Space Surveillance Network. The system is designed to transmit a “fence” of radar energy vertically into space to detect all objects intersecting that fence. The operational advantage of the AFSSS is its ability to detect objects in an un-cued fashion, rather than tracking objects based on previous information.  The disadvantage is the inherent inaccuracy of the data, based on its dated design. The new operating modes at Cavalier AFS and Eglin AFB will provide more accuracy than the AFSSS and still collect un-cued observations.

Coletta’s website SatWatch.org describes the hobby. For example, the diagrams at Orbiting Object RF Reflection 101 at SatWatch.org  show the basics of how an amateur radio receiving station can pick up the reflections of the AFSSS signals when an object passes through the AFSS beams. He also shows the data displays for over 100 different objects that he has tracked.

As a money saving measure, the AF is planning to shut down the AFSSS and use a lower cost system until a new $3B “space fence” is built.

Coletta and other space fence hobbyists won’t have to hang up their receivers, though:

Now, he’ll have to turn his attention to another source of radio waves: Mexican television stations.

“Guess what: Those signals also get bounced down from satellites, meteors and what not,” Coletta said. “You use it just like a space fence.”

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Check out Mike Coletta’s SPACE GAB webcast program “where we Gab about SPACE”.

Amateur/Student Satellite, Space Radio

AMSAT & ISS amateur radio news

Go to AMSAT News for the latest headlines about developments in amateur and student satellites and for updates about amateur radio on the ISS.

ANS 230 Weekly AMSAT Bulletin – August 17, 2013:
* AMSAT Journal Mailing Glitch
* AMSAT-NA Board of Directors Ballots Due September 15th
* NASA Fellowship, Internship, and Scholarship Opportunities for Spring 2014
* Hams in Space to Appear at the Joplin Hamfest
* OPUSAT CubeSat to Test Lithium-Ion Capacitors
* NASA Announces Next Opportunity for CubeSat Space Missions
* UK High Altitude Society (UKHAS) Conference, September 7