Tagged: NTSC

SignalsEverywhere Software and Video Updates: Benshi Dash, AI Vibe Coding SDR Apps, Android NTSC Receiver, NOAA SAME Encoder

Thank you to SignalsEverywhere, aka Sarah Rose, for writing in and sharing some updates on what she's been working on recently.

First, Sarah provides an updated video that shows off her Benshi Dash Android application (GithHub, Name-Your-Price Store Download) for VR N76, UV Pro, and other similar handheld radios with Bluetooth connectivity. 

Benshi Dash | The Ultimate Radio Dashboard for VR-N76 UV-PRO Etc

Next, she notes that she uploaded a video showing the power of Google's Gemini AI, and how she was able to use it to vibe code a HackRF TV transmitter program on Linux in just a few minutes.

Vibe Coding a TV Transmitter on Linux with a HackRF

Next, she mentions that she also built an RTL-SDR NTSC Receiver for Android, based on the TVSharp decoder. It is available on GitHub and via her name-your-price store, with a $0.00 minimum spend. 

RTL-TV. An NTSC video decoder for Android and RTL-SDR.
RTL-TV. An NTSC video decoder for Android and RTL-SDR.

Finally, Sarah writes that she has also created a NOAA SAME weather encoder for use with a HackRF on Linux or Android. This allows users to transmit NOAA SAME (Specific Area Message Encoding) alerts, which are weather alerts typically transmitted on the NOAA Weather Radio frequency, transmitted around 162 MHz. The software is available via GitHub, or via her store for $10 (Linux edition / Android edition).

NOAA SAME Transmitter
NOAA SAME Transmitter

SignalsEverywhere Android Project Updates: Satellite Tracker, HackTV NTSC Transmitter, OBS To HackTV, PacketShare and More

Recently, Sarah Rose Giddings (aka SignalsEverywhere) has been actively developing several radio and SDR based projects for Android, and she would like to provide an update on them.

First, as mentioned in a previous post, Sarah has been developing APRS.chat, an online mailbox system for APRS messages sent over RF. She has also been making progress on various other projects, including various useful Android apps, which she has updated interested people on in her latest livestream.

Hangout Chat | Linux | HackRF NTSC Transmission | Android APPS and More!

Some of the links to the Android software she's working on have been provided below:

Works with Benshi Protocol Radios (VR-N76 UV-PRO etc)

Stuff Created After The Livestream

Help beta test Play Store Releases (Benshi Dash, Benshi Commander, APRS Chat): https://docs.google.com/forms/d/e/1FAIpQLSfNTrCBofQYam6f6CrZ8XxTxZw2vlOiaD6ehGs5NBOAbKkHWw/viewform?usp=header

Screenshots from Sarah's HackTV NTSC Transmitter
Screenshots from Sarah's HackTV NTSC Transmitter

uAVD: Analog Video Decoder Windows Software for SDRs

Thank yoy to Viol Tailer for submitting news about the release of his new software called "uAVD - Analog Video Decoder". uAVD is capable of demodulating the following:

  • AM (broadcast analog television - NTSC, PAL, SECAM)
  • FM (FPV drone video links)
  • RAW (composite output from VHS, camcorders, game consoles)

The software uses the uSDR software as a host, and it passes the IQ passband stream to the uAVD via a uSDR-TCP link. uSDR is a lightweight general purpose multimode software defined radio receiver Windows application that we have posted about on the blog in the past. Currently, it supports RTL-SDR, AirSpy, BladeRF, HackRF, FobosSDR, and LimeSDR devices.

The software supports full color and grayscale modes. With a wideband receiver, it will be possible to receive full-color video. With the reduced bandwidth available with an RTL-SDR, only grayscale will be available.

The code is not open-source, but the software is freely available from SourceForge.

The image below shows it being used to receive video from a camcorder composite video output. A FobosSDR used in direct sampling mode is used to receive the signal.

uAVD Receiving Camcorder Composite Video via the Direct Sampling Input in FobosSDR
uAVD Receiving Camcorder Composite Video via the Direct Sampling Input in FobosSDR

Below is a video from a user of the software demonstrating it in action.

uSDR and uAVD analog video decoder

SignalsEverywhere: Using HackTV to Transmit Analog Television with a HackRF

Over on her YouTube channel SignalsEverywhere, Sarah has uploaded a new video showing how to use a program called 'hacktv-gui' to transmit analog TV signals using a HackRF software defined radio. Analog TV standards such as PAL and NTSC have been phased out in most of the world in favor of digital TV standards instead. However, transmitting these yourself can be a fun experiment that may help breathe life into old television sets.

In the video Sarah explains how to use the hacktv-gui and hacktv software, and how to create a video transmission. She mentions how hacktv also supports the use of a FL2K device, which is a cheap VGA adapter that can be used to transmit signals.

HackTV | Analog Television Transmission with a HackRF SDR

Decoding the RF Output of a VCR with an RTL-SDR

Over on YouTube use Scelly has uploaded a video showing how he has used an RTL-SDR dongle and the TVSharp SDR# plugin to decode video from the RF output of an old VCR (videocassette recorder). VCR players were designed to output the same PAL or NTSC signal that old analog TV transmissions used, and the RF output of the VCR was connected directly to the TV's antenna input.

The TVSharp plugin for SDR# can be used to decode these signals, however as the bandwidth of PAL/NTSC signals is much larger than the 2.4 MHz provided by the RTL-SDR, only a black and white image can be received. Scelly writes:

RF Output from VCR connected directly to input of my RTL-SDR. The RF output is tuned to channel 22 (487.25 MHz), and as the signal is so wide, my RTL-SDR can only display the luminance data (black and white video) and audio, although not at the same time. If I had two RTL-SDRs or an SDR with a larger bandwidth, I could have both audio and video playing at the same time.

The video playing is "The Prince of Egypt" on VHS Video Cassette.

Decoding RF Output of a VCR with RTL-SDR Dongle

Decoding 5GHz NTSC Video from Drones with a HackRF, DragonOS and SigDigger

Over on his YouTube channel Aaron has uploaded a video showing how we can SigDigger to decode analog NTSC video from a drone camera which is transmitted at 5.7 GHz. SigDigger is a rapidly evolving SDR program for Linux and MacOS that has a lot of built in functionality for inspecting signals in more depth. Although not specifically designed for it, the Symbol Stream viewer in SigDigger can be used to display NTSC Analog Video. Aaron writes:

For the most part, the older an analog modulation is, the easier it is to get basic results when decoding. TV receivers were rather dumb back in the day, basically fast fax machines glued to an off-band FM radio receiver. Receiver circuits were also slow, and the signal had lots of invisible blank spaces in the borders so that the cheapest TVs could switch to the next line in time. The invention of Teletext leveraged those blanks in order to carry digital information and color information was embedded as an additional narrowband signal in the gaps in the spectrum.With this in mind I wanted to take a look at decoding analog video transmissions from drones. While some drones have moved to more effective digital compression and channel transmission technologies allowing for high definition video, there’s still drones using RC-like communications and the FPV video link is pure FM-modulated NTSC.

Searching the internet provided few results on how I could go about using low cost equipment, such as the HackRF One, to decode drone feeds. After an extensive search I decided to start looking at Linux based software defined radio applications I was already familiar with. By chance I happened to be working with SigDigger, a free digital signal analyzer. It has been discussed on RTL-SDR.com and more recently on Signal Lounge (https://signal-lounge.com/2020/05/05/sigdigger-for-signal-analysis/). It is also included in my own creation, DragonOS (https://sourceforge.net/projects/dragonos-lts/)

After a brief email exchange with the developer it was brought to my attention that visualizing analog video transmission is possible in SigDigger (although with no color information, of course). Since SigDigger supports the HackRF and the HackRF provides coverage in the 5ghz band, it was now possible for me to try to decode a 5ghz drone video feed. I’ve documented the process and my results on my YouTube channel. I should point out that this is currently a side feature of SigDigger and currently lacks synchronization. The symbol view area I used in the video is not made for this. It is meant to display symbols and symbols patterns which, due to its behavior, can incidentally show the contents of analog TV and weather faxes with lots of manual adjustments.

While the SigDigger developer makes mention of plans to include an embedded generic analog TV viewer and possibly add the ability to automatically sync video, there’s currently no timeframe on when that might become available.

SigDigger Decoding NTSC Video from a Drone Camera
SigDigger Decoding NTSC Video from a Drone Camera
DragonOS LTS SigDigger demodulating a 5 GHz analog video/FPV drone link (HackRF One, SigDigger)

We note that if you're interested in PAL/NTSC decoding, there is also the excellent TVSharp plugin for SDR# available.

Broadcasting Analgoue NTSC TV with a $7 ESP8266

The ESP8266 is a $7 WiFi module that can be used to give any microcontroller access to a WiFi network. It is designed for creating Internet of Things (IoT) devices and has various features such as it’s ability to host it’s own web applications. The ESP8266 also has a I2S output with DMA support. By hooking up this I2S output pin to a short wire, YouTuber CNLohr has demonstrated that he is able to use the ESP to broadcast full color NTSC TV.  This works in a similar way to how PiTX works, by using the pin to modulate a radio signal. CNLohrs code note only broadcasts color NTSC, but also provides a full web interface for controlling it.

In the first video CNLohr shows off his initial work at getting the NTSC output working and in the second video he shows color working. Later in the second video he also uses an RTL-SDR to check on the NTSC spectrum that is being output.

Broadcasting Analog TV on an ESP8266!

Broadcasting COLOR Channel 3 on an ESP

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