BATC Forum

As a newcomer to DATV I am exploring the Portsdown menu and getting a little confused by some of the things I find.

I am using Portsdown 4 plus a PiCam on transmit side, with Pluto, Eagle-eye mini and USB sound card dongle plugged in USB. Then Minitioune V2 and PC to receive on 437MHz, 333kS/S, S2QPSK.


Noted that
1)the USB sound card is essential to transmit pictures from either camera, though test card etc. work without it.
2)PiCam picture is displayed on the Pi screen when transmitting but Webcam picture is not.
3)PiScreen option for picture selection source is greyed out, but otherwise works as would be expected.

Having got pictures working and looking at the Sound source menu "Bleeps" seems a great idea to test the sound side, however I have not managed to receive any.
Selecting PiCam Video and USB sound work fine with external audio signal.
Change to Bleeps and there is no RF output.
Change to Test Card and bleeps; there is an output but no picture until Minitiouner changes the Audio PID to 4096; Putting it back to 257 loses the picture and still no sound.

Setting the sound to "No Audio" behaves somewhat differently in that I get some RF when using Test card but also using PiCam. Again, the picture is decoded only if the Audio PID is set to 4096. There is no RF if Webcam is selected.

The only WIKI page I found about the sound bleeps was written more than 4 years ago so presumably for previous generation of Portsdown/pi/OS.
(Accepting, of course, that Portsdown is a work in progress, maybe the bleeps are being "retired")

I believe 257 is the standard Audio PID used by BATC members and is the default in Portsdown, so where is the 4096 coming from? Any other information that would help me figure out what will work or not and why?

73, Ken

Hi Ken

Pleased that you are exploring Portsdown.

There are some historical anomalies in the Portsdown 4 menus. If there was a professional full-time development team, these would have been ironed out, but as it's only me there just isn't the time (or motivation) to fix them. The Portsdown is approaching 30000 lines of code, most of it written by me, so I'm sure that you'll understand.

For Portsdown 2020 development I did try to disable, or at least grey-out, non-working button combinations. During Portsdown 4 development, so many new capabilities were added that it became impractical to continue that effort, and I have moved towards an "enable all selections, but only some will work" approach.

I have a "Portsdown 4 Next Generation" project in mind that will use the same hardware, but with rewritten software that would be easier to maintain and without the historical aspects. I just wish that there 9 days in each week and I could do it!

Some specific answers:

• I think that if you select Audio to "None", you should be able to transmit pictures from Cameras without microphones (although I have not tested this recently). I may not have implemented this for the Eagle-Eye Mini.
• Only Pi Cam and Test card pictures are displayed during TX. I have not attempted to display webcam or captured pictures while transmitting, although they can be previwed before TX (from Menu 2).
• I wasn't aware that Pi Screen TX worked with Pluto. Not something that I tried to get working!
• The bleeps were only initially implemented for MPEG-2 video encoding, and as the Pluto only does H264, I have not implemented bleeps for Pluto. I have not ever tested bleeps on the Portsdown 4.
• MiniTiouner is fussy about PIDs. The Portsdown and Ryde receivers have been designed to be more tolerant. The default Portsdown audio PID should be 257 - it may be that you have found a setting combination where it is undefined, and so gets set to 4096 either in the TX or in the RX software.

Anyway, will we see you on QO-100 soon?

73

Dave, G8GKQ

Hi Dave,
Thanks for a prompt and detailed reply to my query. To say I will be on QO100 "soon" is probably a bit optimistic, but having a signal crossing the room successfully is a start and gives confidence to proceed. I have yet to make a start on the RF side but that is stuff I understand!

73, Ken