Portsdown 2018 Stretch Software News

Discussion about this major DATV Project. See also https://wiki.batc.tv/The_Portsdown_Transmitter
G8GKQ
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Re: Portsdown 2018 Stretch Software News

Post by G8GKQ » Mon Aug 06, 2018 9:53 am

Hi Mike

As discussed yesterday, we did a number of updates and new card builds on Saturday which all worked perfectly. I think that your cards might have been corrupted by some of the testing that I had asked you to do - not sure if I should say sorry or thanks, both apply!

I suggest that you rebuild both your cards from scratch using the instructions here:https://github.com/BritishAmateurTelevi ... ch-version.

You can back up some of your settings(but not all) on to a USB stick before you do the card rebuild using an option in the advanced setup menu.

Dave

PS - Jessie is still being updated, but I would prefer that everyone moves to the Stretch version as soon as possible

m0xtd
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Joined: Sat Dec 12, 2015 7:55 pm

Re: Portsdown 2018 Stretch Software News

Post by m0xtd » Mon Aug 06, 2018 10:55 pm

Hi Dave,

Update installed without a problem and also added the Lime Mini support.

Can confirm that I have now got the Lime Mini tx-ing and being received on a Minitiouner. Signal keeps dropping out every so often but that just might be my setup on the bench here. Will continue and let you know. Can the Lime Mini be used instead of the RTL-SDR for the spectrum view?

Couple of quick comments for you on the Release 201807290 software. I'm not sure of this was present before as I only noticed it today. I also realised that I used the June update of Stretch by mistake but so far, everything appears to function ok.

1. Change to Pi OTP settings. If you provide a MPG2/VC1 decode string in /boot/config.txt, that change is now stored in some of the one time programming entries and no longer needs to be quoted in the config.txt file.
"vcgencmd otp_dump" shows the OTP parameters and 45/46 are the MPG2/VC1 codec entries.
What this means is that a R-Pi may now be licensed for MPG2/VC1 decode but that there is no entry in the config.txt startup file. Might affect how you report this on the MPEG2 license menu.

2. I think I am right in that the only way to enter my BATC stream details is to directly edit one of the settings files (portsdown-config.txt) and change the streamkey parameter. Whilst there (and this was before I ran any setup from the touchscreen) I edited the call and locator parameters to be my callsign and qth. However, on rebooting the Portsdown and checking the bearings of other users, the software was quoting my correct callsign but wrong locator (quoted IO90.... ). Had to use the update facility on the menus to enter my locator again, after which bearings where being correctly reported. Probably not a problem but might suggest that different functions are reading locator codes from different locations.

3. (This was observed on previous installations) Is there a way to leave the Portsdown on a specific output band on shutdown? Only asking this as mine seems to always want to enable the 2m output on shutdown, irrespective of which band I was experimenting with?

4. Constellation diagram. This is something I have observed - I have no clue if this is to be expected or indicates that I have further tuning to do on my setup. When I use a DTX1 or the LimeMini as a source for a signal, and use MiniTiouner as the decoder/display, the constellation tends to be very concentrated on the four points. The signals are very concentrated and very symmetrical. However, using the Portsdown, the constellation patterns appear differently - with one (the lower right) being in the expected position whilst the other three appear to be shifted slightly down and to the right. I will get some pictures tomorrow and update this but just wondering of there is anything else I need to do on the setup?

I also have the streaming working and getting some nice results. Laptop is taking a bit of a hammering and is starting to show its age (it's a Core 2 Duo T9300 with 4GB) though.....

Really pleased with my build and thanks for all your help.

73s
Ciaran
M0XTD

G8GKQ
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Re: Portsdown 2018 Stretch Software News

Post by G8GKQ » Tue Aug 07, 2018 9:15 pm

Hi Ciaran
m0xtd wrote:
Mon Aug 06, 2018 10:55 pm
Can confirm that I have now got the Lime Mini tx-ing and being received on a Minitiouner. Signal keeps dropping out every so often but that just might be my setup on the bench here. Will continue and let you know. Can the Lime Mini be used instead of the RTL-SDR for the spectrum view?
Lime Mini support is very experimental at present. The BATC Filter-Modulator is currently the better option. Spectrum View is RTL-SDR only.
m0xtd wrote:
Mon Aug 06, 2018 10:55 pm
1. Change to Pi OTP settings. If you provide a MPG2/VC1 decode string in /boot/config.txt, that change is now stored in some of the one time programming entries and no longer needs to be quoted in the config.txt file.
"vcgencmd otp_dump" shows the OTP parameters and 45/46 are the MPG2/VC1 codec entries.
What this means is that a R-Pi may now be licensed for MPG2/VC1 decode but that there is no entry in the config.txt startup file. Might affect how you report this on the MPEG2 license menu.
I use the command

Code: Select all

vcgencmd codec_enabled MPG2
to check the OTP settings, so have this covered.
m0xtd wrote:
Mon Aug 06, 2018 10:55 pm
2. I think I am right in that the only way to enter my BATC stream details is to directly edit one of the settings files (portsdown-config.txt) and change the streamkey parameter.
No - you can set this parameter from the Console when you select Stream as an output. It will be available from the touchscreen as soon as I have time to implement the code.
m0xtd wrote:
Mon Aug 06, 2018 10:55 pm
Whilst there (and this was before I ran any setup from the touchscreen) I edited the call and locator parameters to be my callsign and qth. However, on rebooting the Portsdown and checking the bearings of other users, the software was quoting my correct callsign but wrong locator (quoted IO90.... ). Had to use the update facility on the menus to enter my locator again, after which bearings where being correctly reported. Probably not a problem but might suggest that different functions are reading locator codes from different locations.
There are 2 locators stored. A 6-figure one for video captions, and a 6 or 8 or 10 figure one for bearing and range calulations. If you use the intended user interface (either touchscreen or console), they are both updated correctly. If you try to hack the config files without doing both, you will not get the right result.
m0xtd wrote:
Mon Aug 06, 2018 10:55 pm
3. (This was observed on previous installations) Is there a way to leave the Portsdown on a specific output band on shutdown? Only asking this as mine seems to always want to enable the 2m output on shutdown, irrespective of which band I was experimenting with?
The band selection is determined by the voltage on 2 GPIO lines. When you shut down the RPi, these go to zero volts, so select the 71 MHz band. I can't get electricity out of nowhere!
m0xtd wrote:
Mon Aug 06, 2018 10:55 pm
4. Constellation diagram. This is something I have observed - I have no clue if this is to be expected or indicates that I have further tuning to do on my setup. When I use a DTX1 or the LimeMini as a source for a signal, and use MiniTiouner as the decoder/display, the constellation tends to be very concentrated on the four points. The signals are very concentrated and very symmetrical. However, using the Portsdown, the constellation patterns appear differently - with one (the lower right) being in the expected position whilst the other three appear to be shifted slightly down and to the right. I will get some pictures tomorrow and update this but just wondering of there is anything else I need to do on the setup?
This could be caused by one of 3 things: LO leakage from the ADF4351 to your receiver, lack of an LO filter, or operation at 71 MHz below the specification of the IQ modulator. The fact that the signals are not generated by an SDR means that the points are not as sharp.

Hope that helps you understand some of the issues!

73

Dave

g0mjw
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Re: Portsdown 2018 Stretch Software News

Post by g0mjw » Fri Aug 10, 2018 10:28 am

G8GKQ wrote:
Mon Aug 06, 2018 9:53 am
Hi Mike

As discussed yesterday, we did a number of updates and new card builds on Saturday which all worked perfectly. I think that your cards might have been corrupted by some of the testing that I had asked you to do - not sure if I should say sorry or thanks, both apply!

I suggest that you rebuild both your cards from scratch using the instructions here:https://github.com/BritishAmateurTelevi ... ch-version.

You can back up some of your settings(but not all) on to a USB stick before you do the card rebuild using an option in the advanced setup menu.
I tried this and it would not work on IQ mode at all. After 5 re-installs I finally figured out that the problem is that the default audio was set to auto rather than off as it apparently needs to be if there is no audio device connected. I am now wondering if this is behind several other past problems.

G8GKQ
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Re: Portsdown 2018 Stretch Software News

Post by G8GKQ » Fri Aug 10, 2018 6:34 pm

Mike and I have now found the cause of his problems. He was using the "Save Settings to USB Drive" function on a very old (more than 1 year) Portsdown and then importing the settings to the latest build. There were a number of incompatibilities, but the one causing the most problems was that analogcamname was set to /dev/video0 and should have been set to auto.

I am going to rebuild the "Save settings to USB" functionality soon, but the main thing to note from Mike's experience is that it will only work if the exporting and importing Portsdowns use compatible settings. Unfortunately, these settings do change over time as the Portsdown gains new features.

Dave, G8GKQ

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