Portsdown 4 - New Update 202008050

Discussion about this major DATV Project. See https://wiki.batc.org.uk/The_Portsdown_Transmitter
G8GKQ
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Re: Portsdown 4 - New Update 202008050

Post by G8GKQ » Mon Aug 10, 2020 5:16 pm

Hi Gareth

Portsdown 4 needs to be a new build. It is not a migration/update from the Portsdown A27 - so that is why you are having all the problems.

So a card rebuild should sort everything out.

Dave

radiogareth
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Re: Portsdown 4 - New Update 202008050

Post by radiogareth » Mon Aug 10, 2020 8:22 pm

Thanks Dave, I read the relevant wiki and it's busy doing its setup now :-)
Gareth

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Re: Portsdown 4 - New Update 202008050

Post by radiogareth » Wed Aug 12, 2020 11:18 am

Assuming I choose the required protocols for Pluto operation, does this mean I can do DATV on 5.8GHz with my Portsdown 4/Pluto? Currently using DATVExpress to drive a pluto.
Gareth

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Re: Portsdown 4 - New Update 202008050

Post by G8GKQ » Wed Aug 12, 2020 11:59 am

Hi Gareth

Yes. Not yet tested, but should work.

Dave

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Re: Portsdown 4 - New Update 202008050

Post by radiogareth » Wed Aug 12, 2020 4:35 pm

Interesting, a quick play with a pair of Plutos this afternoon, all OK up to and including 13cm.

3.4GHz doesn't like the C920 but transmits a test card, 5.665 lights up the camera but doesn't TX camera or testcard.....or any RF....

TX confirmed as functioning on Langstone SW, listening with SDR#. For DATV I was using the Amsat DVBS GUI, which, when it works, its great......

I did notice that when I stopped transmitting on 3.4, the carrier continues for about 10 more seconds after the screen reverts to the main menu.

Gareth

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Re: Portsdown 4 - New Update 202008050

Post by G8GKQ » Wed Aug 12, 2020 5:22 pm

Hi Gareth

The TX over-run after deselecting transmit is normal with the Pluto on Test Card, Contest numbers and (when implemented) Desktop modes. Something to do with ffmpeg that I haven't got to the bottom of yet.

Please confirm that you selected 3.4 and 5.6 GHz by entering the frequency in "direct" mode, not by selecting a band; when correctly entered, the Band/Tvtr should show as 13 cm for both these frequencies. The original concept was that 3.4 and 5.7 GHz would be "transverter" bands, so there is a pre-programmed LO frequency for the bands labelled as 9_cm and 6_cm.

I have certainly seen RF at 5.7 GHz, but need to do some more testing.

Dave

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Re: Portsdown 4 - New Update 202008050

Post by DL5BCA » Wed Aug 12, 2020 6:28 pm

Hello Dave,

here is a short description of my test (at 31 degrees warm).
I've just sent on 13cm with Pluto.
DVBS H264 SR2500 FEC1 / 2.
EasyCap and Testcard work.
The Pluto does not send PI Screen and Contest Numbers.
I don't have PICam and Webbam C920.

In fact, it takes longer to switch on and off with Testcard than with EasyCap.

When I enter 3400 or 5700mhz, Band/Tvtr shows 13_cm.
I always have crazy ideas.
Please don't be surprised.

radiogareth
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Re: Portsdown 4 - New Update 202008050

Post by radiogareth » Wed Aug 12, 2020 7:44 pm

Thanks Dave. I was using 'keyboard entry' (desired frequency) which works on 3.4GHz, not on 5.6.
I just tried the transverter buttons - 9cm/3.4 works, 6cm/5.6 does not (assuming I'm looking in the right bit of spectrum of course....).
Not exactly a priority.......could we have the carrier button on Pluto, it would help with sanity checks ;-)

Not the weather for logical thinking....

Gareth

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Re: Portsdown 4 - New Update 202008050

Post by G8GKQ » Wed Aug 12, 2020 8:09 pm

Thomas - my apologies. Contest numbers is only available in the Dev version at the moment (it was done as a quick job for someone to use in our contest at the weekend), and I have only just implemented Pi Screen on my test system. They'll both be in the next full release, and like testcard they will take longer to switchoff.

Gareth - more testing of 5.6 GHz required here, but I can't bring myself to turn on the enormous HP141T shack-heating spectrum analyser at the moment! Carrier mode for Pluto is on the to-do list, but is not straightforward as it is effectively another output device. I'm looking at this http://www.albfer.com/en/2020/08/10/plutotx/ as the most likely candidate approach.

Dave

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Re: Portsdown 4 - New Update 202008050

Post by DL1BJV » Thu Aug 13, 2020 3:23 pm

Hi Dave,

it takes 2 minutes and 50 seconds to complete a reboot on my Portsdown 4 running update 202008050 with no devices connected.
Alain, F1CJN has experienced something similar and you replied that it can take up to 90 seconds. I have built a new SD Card but no change.

Anyone else having such a long reboot cycle?

Wolfgang

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