Tagged: tv#

Exploring Russian and International Analog TV From Leaky Cable TV Networks via the Airspy Server Network

Thank you to RTL-SDR.COM reader Micha for submitting a story about how he has been able to use SDR# and the Airspy Server Network to explore cable TV stations across the globe via cable TV signal interference.

If you were unaware, the SDR# software from Airspy.com has access to the Airspy Server Network, which is a collection of public Airspy SDRs available all over the world that can be accessed freely over the internet. To access these SDRs simply select "Airspy Server Network" as the source in SDR#, and click on the "..." button next to the server address entry. A map will pop up where you can select from SDRs all over the world.

Using Airspy SDRs in Russia, and in other countries (Guatemala, Brazil, Chile, Uruguay, Mexico, Dominican Republic, Argentina, Indonesia, Vietnam, Micha found that there were several analog TV signals found at frequencies that should not have terrestrial TV signals there. Upon further investigation, he realized that these are actually cable TV signals that are leaking and causing interference across the RF bands. Micha notes that he's also observed how the leaking signals often change in frequency and intensity too, making it difficult to keep track of them.

Combined with the TVSharp SDR# plugin, Micha was able to recover some (very rough) images from these interfering signals. Micha has provided several images shown below that demonstrate Russian cable leakage, as well as for Mexico and Argentina.

Using the RTL-SDR Blog V3 as a DVB-T Receiver in OpenPli Enigma2

The RTL-SDR hardware began its life as a DVB-T TV receiver USB stick, but these days it is rarely used for this purpose. However, in countries where DVB-T hasn't been upgraded to DVB-T2 it is still possible to use the RTL-SDR for TV reception.

Recently, RADIOTO bg from DXing.org wrote in and wanted to share with us his video showing how to use the RTL-SDR V3 for DVB-T reception in OpenPli Enigma2. OpenPli is an open-source Linux distribution for TV set-top boxes and Enigma2 is the TV application it runs.

RADIOTO's video shows a step-by-step guide to setting up the RTL-SDR in OpenPli. The procedure is relatively simple, just requiring the user to select the correct driver for the RTL-SDR via the set-top menu.

How to make rtl-sdr v.3 as a additional DVB-T tuner in enigma2 receiver (OpenPli) Manual

Android App Aerial TV Banned from Google Play – Now Available on Amazon

Aerial TV is an Android app that allows you to watch DVB-T TV with an RTL-SDR on a mobile device. We posted about Aerial TV back in April and it was available on the Google Play store back then. Unfortunately Aerial TV has recently been banned from the Google Play store as apparently the app can be used to display copyrighted material from TV. The author writes the following on a Facebook post:

Google Play has suspended Aerial TV due to “[Aerial TV] claims to provide copyrighted contents from TV channels”. According to Google apps that display live TV are of “questionable nature”. I am trying to clarify what they mean. I would like to apologize to all affected users. If you have any concerns, feel free to get in touch with Google directly.

This is quite odd and probably a mistake. But if you are looking for Aerial TV it is now available on the Amazon app store with a current 35% discount. If you bought the app on the Google Play store then to get new updates you will need to uninstall it, contact the developer for a refund, and then purchase it again on the Amazon store. More info about that is available on the Facebook page. Updates about it’s availability will always be provided on the official website at aerialtv.eu.

Transmitting Analog TV Broadcasts with a HackRF

Over on the user submitted hackaday.io community, user marble has shared his work about using a HackRF to transmit PAL analog colored TV images with his rad1o (the rad1o is a slight variation of the HackRF One) using a GNU Radio flowgraph.

In his submission he shares a tutorial that explains the theory behind the PAL analog video standard. He explains the different components of the PAL signal, including the luma (black and white part), frame rates, and modulation. He then goes on to explain how color is encoded onto the PAL by using Quadrature Amplitude Modulation (QAM).

Finally in the files section marble also supplies us with the GNU Radio flowgraph which can be used to transmit PAL video with a HackRF.

PAL test signal transmitted with a HackRF.
PAL test signal transmitted with a HackRF.

Watching ATSC TV with an SDRplay SDR and GNU Radio

ATSC is the digital HD TV standard used within the United States and Canada. It is 6 MHz wide so the RTL-SDR with its maximum bandwidth of about 2.8 MHz cannot decode this signal. However, higher end SDR’s such as the SDRplay, Airspy and HackRF have larger bandwidths that can easy cover 6 MHz.

One SDRplay owner was able to figure out a way to decode ATSC by using a decoder written in GNU Radio. With the process the author used we note that other wide band SDR’s such as the Airspy and HackRF should also be capable of achieving the same results.

The process the author used was to first record a RAW IQ WAV file in HDSDR in Windows, making sure that any DC spike correction is applied. The WAV file is then opened in a premade GNU Radio flow graph in Linux and processed into an MPEG file. The process is not real time. The authors article shows a step by step tutorial on how its done.

In an update post to his results the author also notes that to successfully do a recording at the maximum SDRplay bandwidth of 8 MHz a RAM disk or perhaps SSD is required so that samples are not dropped.

An ATSC signal shown in HDSDR received with an SDRplay
An ATSC signal shown in HDSDR received with an SDRplay

New SDR# Plugin: PAL / SECAM TV

The SDR# plugins programmer over at rtl-sdr.ru has recently released a new plugin which allows the decoding of PAL / SECAM TV images from within SDR# (note link in Russian, use Google translate or see the download link at the bottom of the page). The author also writes that if you are using a newer software defined radio like an Airspy, you can also receive the audio channel using the SDR# multiple VFO plugin.

We note that there is also the TVSharp software by the same author which is a standalone program that can decode PAL and NTSC.

PAL / SECAM TV SDR# Plugin
PAL / SECAM TV SDR# Plugin

Receiving NTSC Analogue TV with GNU Radio and an RTL-SDR

Over on GitHub user kik has uploaded a tutorial and code showing how to decode NTSC analogue TV in GNU Radio and an RTL-SDR. The tutorial is in Japanese, but Google translate should be good enough to understand the text. Kik shows us what GNU radio blocks to use and provides the python code needed to display the images on a simulated scope.

If you just want to receive analogue TV signals, try TVSharp.

gnuradiontsc
GNU Radio Decoding NTSC and showing images on a Scope

Using the RTL-SDR as a Cheap TV Satellite Finder

Finding the correct direction to point a satellite for TV reception can be difficult without the right equipment. YouTube user MegaOscarVideos shows us in the video below how he uses an RTL-SDR to accurately aim his satellite for TV reception.

He uses a TV satellite dish with an LNB connected to a bias-T circuit as the receiver, which is then connected to the RTL-SDR. As the satellite is moved he looks for the direction at which the signal level in SDR# increases the most.

RTL SDR as cheap TV Satfinder