Over on YouTube we've seen a good video from channel Ham Radio DX where presenter Hayden shows how to use an RTL-SDR to receive slow scan television (SSTV) images from the International Space Station (ISS). Often the ISS will transmit SSTV images down to earth on the VHF 2 meter bands as part of an event. With an RTL-SDR and simple antenna it's possible to receive those images.
In the video Hayden discusses the SSTV transmission, and demonstrates some SSTV decoding happening in real time as the ISS passes over his location. If you're looking to get started in ISS SSTV reception, this is a good video to get an idea of what's involved. He finishes the video with some useful tips for reception.
Using a RTL SDR Dongle to receive pictures from the ISS! | Software Defined Radio
Thank you to Maksim for submitting news that the International Space Station (ISS) will be transmitting Slow Scan TV (SSTV) in late December to celebrate 20 years of amateur radio operations onboard the space station. The ISS periodically transmits SSTV images during special events throughout the year. You can keep up to date on the ISS SSTV schedule on the ARISS-SSTV site.
An ARISS Slow Scan TV (SSTV) event is scheduled from the International Space Station (ISS) for late December. This will be a special SSTV event to celebrate the 20th anniversary of ARISS operations on the ISS. The event is scheduled to begin on December 24 and continue through December 31. Details to follow later. Dates are subject to change due to ISS operational adjustments.
With an RTL-SDR and a simple V-Dipole from our RTL-SDR Blog V3 antenna kit it is possible to receive these images when the ISS passes over. ISS passes for your city can be determined online, and the SSTV images can be decoded with a program like MMSSTV.
Earlier this year SDRplay updated their SDRuno software to have plugin functionality. This allows third party programmers to implement their own decoders and software which interfaces with SDRuno directly. Recently we've seen some new plugins become public, and in one of their recent blog posts, SDRplay highlights a few new ones.
SDRplay writes the following about three demonstration videos:
The first shows the latest version of FRAN – a FRequency ANnotation programme, developed by Eric Cottrell – it can read SWSKEDS or .s1b memory bank files and display the active stations from the files on the main spectrum window. This is an example of a Community Plugin
Quick Look at the FRAN Plugin (VID558)
FRAN complements the DX Cluster demo plugin provided by SDRplay. This programme displays DX cluster callsigns on the SDRuno spectrum display. A DX cluster is a network of computers, each running a software package dedicated to gathering, and disseminating, information on amateur radio DX activities. With this plugin you can overlay the DX cluster callsigns as they pop up. There’s a choice of how long you let them display and you can control the way in which they appear. Here we show it successfully tuning in to a US station flagged by the cluster. (The receiver was in the UK):
Quick Look at the DXcluster Plugin (VID560)
Finally there’s this new video showing the new plugin for interfacing the software suite from Black Cat Systems to SDRuno enabling DXToolbox, HF WEFAX and Slow Scan TV decodes:
The International Space Station (ISS) periodically schedules radio events where they transmit Slow Scan Television (SSTV) images down to earth for listeners to receive and collect. This time they have scheduled SSTV images for October 9 09:50 - 14:00 GMT and October 10 08:55-15:15 GMT.
With an RTL-SDR and a simple V-Dipole from our RTL-SDR V3 antenna kit it is possible to receive these images when the ISS passes over. ISS passes for your city can be determined online, and the SSTV images can be decoded with a program like MMSSTV.
Fifty years ago Neil Armstrong became the first man to step foot on the moon. This weekend on June 20th and 21st 2019 Amateur Radio operators at the [PI9CAM] team have been transmitting Slow-Scan Television images in commemoration of this historic event at the Dwingeloo radio astronomy station in the Netherlands. This station is the oldest rotatable 25-meter radio telescope in the world.
Slow-Scan Television is a method often employed by ham radio operators to send photos over radio waves. You may be familiar with this from some of our previous articles on the SSTV event held by ARISS for the International Space Station.
Station [S1NDP] has previously sent slow-scan EME images between the PI9CAM team and himself. These images can potentially be heard by anyone within line-of-site with the moon during the operation of this event.
The team transmit in the 23cm band at a frequency of 1296.11 MHz, according to the ARRL even a 2.5 to 3meter dish should be enough for reception assuming you have a 23cm feed for your dish. It will be interesting to see what photos are heard by the end of this event.
Thank you to Alex Happysat for writing in and letting us know about the next upcoming ISS SSTV event which will begin on 11 April at about 18:00 UTC and end on 14 April 2019 18:00 UTC. If you were unaware, the International Space Station (ISS) transmits SSTV images several times a year to commemorate special space related events. SSTV or Slow Scan Television is an amateur radio mode which is used to transmit small images over radio signals.
The images will be transmitted constantly at 145.8 MHz over the active period and they are expected to be in the PD-120 SSTV format. To receive the images you can use a simple RTL-SDR dongle and the MMSSTV software. A tuned satellite antenna like a QFH, turnstile, or tracking Yagi would be preferred, but many people have had good success before using simpler antennas like a V-Dipole. Software like Orbitron, GPredict, various Android apps or NASA's Spot the Station website can be used to determine where the ISS is and predict when it will be over your location.
The next big event will be the ARISS SSTV event that starts Thursday, April 11 about 18:00 UTC and will be operational until about 18:00 UTC on Sunday, April 14. Since this event will run continuously for 72 hours, folks in the higher latitudes should have a pretty good chance to receive all 12 of the images. Operators in the mid latitudes should be able to get most of them depending on location. Good Luck and Enjoy!
Alex also mentions that for this and other ISS events AMSAT Argentina is handing out ARISS-SSTV Diplomas to amateur radio operators who receive, record and upload at least 15 images received from the ISS, in at least two different radio operation with a month or more in between then.
If you cannot set up a receiver, it is possible to use R4UAB's WebSDR which will be available directly at websdr.r4uab.ru. However, note that internet reception is not valid for the AMSAT Diploma. An example of WebSDR SSTV reception and decoding from a smaller ISS SSTV event held a few days ago is shown below.
Over on his YouTube channel SignalsEverywhere, Corrosive has uploaded a new video tutorial showing us how to transmit with a PlutoSDR and SDRAngel. His tutorial goes over the initial set up steps, selecting a modulator and changing modulator settings. He then goes on to demonstrate transmitting CW Morse code, using a CTCSS squelch tone and transmitting a Robot36 SSTV image via Virtual Audio Cable and MMSSTV.
RPiTX is software for the Raspberry Pi which can turn it into a 5 kHz to 1500 MHz transmitter which can transmit any arbitrary signal. In order to transmit the software does not require any additional hardware apart from a wire plugged into a GPIO pin on the expansion header. It works by modulating the GPIO pin with square waves in such a way that the desired signal is generated. However, although additional hardware isn't required, if RPiTX is to be used in any actual application a band-pass filter is highly recommended in order to remove any harmonics which could interfere and jam other radio systems.
Earlier this month RPiTX was upgraded to version 2. One of the changes is a new GUI for testing the various transmission modes. Currently it is possible to transmit a chirp, FM with RDS, USB, SSTV, Opera, Pocsag, SSTV, Freedv. There is also a spectrum painter which allows you to display an image on a SDR's waterfall.
The RPiTX v2 update also makes recording a signal with an RTL-SDR, and replaying that signal with RPiTX significantly easier. Previously it was necessary to go through a bunch of preprocessing steps (as described in our previous tutorial) in order to get a transmittable file, but now RPiTX is capable of transmitting a recorded IQ file directly. This makes copying things like 433 MHz ISM band remotes significantly easier. One application might be to use RPiTX as an internet connected home automation tool which could control all your wireless devices.
Finally, another application of the RPiTX and RTL-SDR combination is a live RF relay. The software is able to receive a signal at one frequency from the RTL-SDR, and then re-transmit it at another frequency in real time. Additionally, it is also capable of live transmodulation, where it receives an FM radio station, demodulates and then remodulates it as SSB to transmit on another frequency.