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Old 20th Sep 2022, 1:39 pm   #1
gridrunner
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Join Date: Jun 2008
Location: Manchester, UK.
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Default Working with HackTV

Hello everyone,

I just wanted to give an update on my adventures with HackTV.

Just a bit of background. I’ve recently acquired a 405 line TV from Tas on the forum, a GEC BT318. I haven’t played with 405 line in a good few years and so I’d long ago sold my Aurora converter. When I started casting around for options it became clear that finding a new converter is quite difficult and expensive. What I did notice from googling about was people using a piece of software called HackTV in conjunction with a software defined radio, specifically a HackRF One. This allowed 405 lines to be broadcast from the SDR using a variety of computer sources. I just happened to have a HackRF One handy and so I went about installing it.

There are two builds, a Linux build and a Windows build. I started out with a Linux build running on a Raspberry Pi4. Installation is straightforward by adding the packages listed in the ReadMe of the Github project.

https://github.com/fsphil/hacktv

Another fork of HackTV offers support for emulating a range of retro satellite scrambling systems.

https://github.com/captainjack64/hacktv

What is less than obvious however was the impact a lack of processing power has on HackTV. I’d used the Raspberry Pi because it was handy, but the Pi4 is not powerful enough to run HackTV. What this looks like in practice is a poor signal, with a lack of lock and noise in the picture. This had me fiddling with the antennas, trying a different TV (I was testing with 625 lines initially) and isolating all sources of RF in my shed. What it turned out to be was a lack of CPU power. It’s not a limitation of USB. The Pi4 has two USB3 ports, but the HackRF One (at least my build) only works at USB2.0. USB2.0 can still theoretically deliver 480Mbps and so the bottleneck is clearly elsewhere. A default sample rate of 16Mhz defeated the Pi4 and an older i7 laptop that I own also struggled a little bit. 405 line transmissions are less burdensome at half the sample rate, but a Pi based solution is best avoided.

The Windows distribution of HackTV has to be compiled from source, but a working binary is available here (thanks to Captain Jack!):

https://filmnet.plus/hacktv/hacktv.zip

To this you can add a Java based GUI, here:

https://github.com/steeviebops/hacktv-gui

And you can also stream direct from Youtube by adding yt-dlp, which is a fork of youtube-dl. Youtube-dl is supported, but I didn’t have any luck getting it working.

https://github.com/yt-dlp/yt-dlp/releases/

Just put everything into the same folder.

There are some dependencies if you are running Windows 10 that you need to install (you should use a 64 bit OS):

Visual C++ distribution (x86 version) – to run youtube-dl/yt-dlp

https://www.microsoft.com/en-us/down....aspx?id=26999

Java 17 SDK – to support the GUI

https://www.oracle.com/java/technolo...downloads.html

Here is a screengrab of a Youtube stream of the Queen’s funeral being broadcast by HackTV. I’ve also tested MP4 streaming successfully.

There is talk of the RF amplifier stage in the HackRF being very vulnerable to damage. I don’t have the TX amp turned on for my experiments and the gain is set to 47db. It’s not advisable to attach the HackRF directly to the receiver. I use the ANT500 telescopic antenna that comes with the HackRF kit.

This is an awesome project and I must congratulate the authors. The flexibility of being able to emulate a number of different standards is great, as is the ability to stream from Youtube and from MP4. You do need a reasonably fast, modern PC to operate it, but it doesn’t need to be a monster. I’ve settled on a HP ProDesk 280 G2 i5 6th Gen and it runs just fine. If you want to get into the satellite crypt cards scene, you might need a bit more grunt. The only limitation is that your sources are computer based and so it would be difficult to broadcast an analog source for example.

The HackRF itself sells for around £100-£120 on Aliexpress. Purchasing on there will result in a clone board. The real deal is a bit more expensive but at least you’ll have a warranty and some guaranteed quality. https://www.hamradio.co.uk/sdr/great...rf-one-pd-7799

Hope this helps someone!
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