Composite Video

[gordon]

Having found a spare RPi3 in my junk box, I decided to use that as a source of Composite video to feed a FPV transmitter. I made a new card using the 2018/03/13 version (probably that was the first version) of Rasbian Stretch Lite, as I already had it stored on my PC. All appears to be well apart from the fact that the 4pin jack on the RPi does not produce any video despite having made the selections in the menu. I am using a Logitech C920 cam (also selected). Any suggestions please? One other thing, whilst I'm here, the FPV transmitter, bought on Ebay, claims to work on 5665MHz but it doesn't. The nearest I can get is 5685MHz; the model is a TS 582000, I have not measured the output power but 2 watts is claimed. I shall write that off to experience.
Gordon

[M0SKM]

Hello Gordon,

Did you get the video lead specifically for the RPi?

I ran into the same problem when I used what I thought was a compatible lead; unfortunately they come in different flavours.

On the BATC wiki there is a useful link showing the pinout; it's worth a look if you're not sure.
http://www.instructables.com/id/Raspber ... -Easy-RCA/

[gordon]

Thanks for your reply, unfortunately it does not appear to be as simple as that. I did buy a bespoke lead although I realised later that I could just have soldered some wires onto the bottom of the board.What I am not sure about is whether its possible to get comp. video at the same time as its outputting I and Q signals. Maybe its one or the other . I'm sure that someone will tell me where I'm going wrong.

Gordon

[G8GKQ]

Hi Gordon

Have you installed the Portsdown software on top of Raspbian Stretch Lite? I am not sure that the video output is enabled by default - the Portsdown install script sets it to PAL mode.

Secondly, please confirm that you do not have an HDMI display (or 7 inch touchscreen) connected. Both of these disable the video output, even if it was previously enabled.

Lastly, it is not currently possible (in the Portsdown software) to display the picture from the C920 on the video output; you can display the picture from the PiCam, and some of the Portsdown testcards, but not from a webcam. You can of course transmit the picture from the C920.

Dave, G8GKQ

[gordon]

Hello Dave,

Many thanks for your posting. I have swapped the C920 for a Pi cam and now have Composite video from the 4-pole jack socket.

Gordon(G3ZYL)