Possible enhancements / wishlist

Forum for discussion about the Langstone Microwave Transceiver that shares some features with the Portsdown. Wiki: https://wiki.microwavers.org.uk/Langstone_Project
g8gtz
Posts: 1776
Joined: Wed Apr 07, 2010 6:26 pm

Possible enhancements / wishlist

Post by g8gtz » Tue Apr 21, 2020 8:58 am

Removed from wiki and put here to enable discussion:

====Waterfall display====

Colin G4EML says
I would really like to add a waterfall display but at the moment I can’t determine the best way to do that. GNU Radio can do it but only in desktop mode. I think it really needs a new (or modified) GNU Radio module that analyses the spectrum and outputs values to a file. I could then read the file and add the display.

====Digital modes encoder / decoder====

On board WSJT capability

====Direct keyboard entry for frequency====

Touch screen keyboard for freq entry

====Split frequency operation====

Split Tx / Rx operation for use on QO100 etc

====Rewrite in C====

This first release is only seen as a proof of concept, ideally the project will be re-written in C and perhaps merged back in to the Hayling project.

g0mjw
Posts: 2568
Joined: Sat Sep 20, 2014 9:15 am

Re: Possible enhancements / wishlist

Post by g0mjw » Tue Apr 21, 2020 10:16 am

There are some Gnuradio modules that do the waterfalls via QT. I wonder if it's possible to write these images to a file instead.

Mike

M0DTS
Posts: 684
Joined: Sun Feb 24, 2008 9:03 pm

Re: Possible enhancements / wishlist

Post by M0DTS » Tue Apr 28, 2020 2:03 pm

I've done a bit of work today geting a waterfall display to work.

Fairly minimal changes really...
Added 'Log Power FFT' block then 'file sink' block to the output of freq_xlating_fir_filter_xxx_0.
This is set to give 512 points fft across 44.1KHz spectrum, i did also tweak the width of the filter slightly for looks..!
The display code is inside LangstoneGUI.c, probably 40 lines or so.

Here is the display:
fft 44khz.jpg
fft 44khz.jpg (134.57 KiB) Viewed 8886 times
span is 44.1KHz and tunes along with the receiver frequency.


Modified code is here so far:https://www.dropbox.com/sh/h4kmrf9kj5o6 ... xGW8a?dl=0

Rob

Edit: Spectrum graph is in there now too.
Last edited by M0DTS on Tue Apr 28, 2020 9:17 pm, edited 2 times in total.

g4eml
Posts: 752
Joined: Thu Apr 26, 2018 9:36 am

Re: Possible enhancements / wishlist

Post by g4eml » Tue Apr 28, 2020 2:59 pm

Hi Rob,

That looks encouraging, and sounds easier to do than I expected.

I doubt we have enough processing power to have a very wide spectrum display but even a few 10s of Khz is useful when looking for signals that may be slightly off frequency.

Colin.

M0DTS
Posts: 684
Joined: Sun Feb 24, 2008 9:03 pm

Re: Possible enhancements / wishlist

Post by M0DTS » Tue Apr 28, 2020 3:14 pm

I guess it depends on the resolution expected.
It will do the full 0.5MHz fine with 512 points but not much clarity of signals, i'm not quite sure how to manipulate the points in a big fft down to 512 pixels.
My sdr knowledge is minimal ;-)

Rob

g4eml
Posts: 752
Joined: Thu Apr 26, 2018 9:36 am

Re: Possible enhancements / wishlist

Post by g4eml » Wed Apr 29, 2020 9:51 pm

Hi Rob,

I have just downloaded the waterfall mods and tried them on my Langstone.
I had to revert the IP address back to the default and reduce the buffer sizes. (they were deliberately set low to keep the latency down, but it sounds like that might have to be sacrificed if you want to run the Pluto remotely)

I initially had a problem with it stopping after one screenfull but that was because the file sink was writing to a regular file and not a pipe.
It is necessary for the pipe to be created before the file sink is started otherwise it creates a regular file, which then just grows larger and larger.
It should be possible to create the pipe in SSB_TRX.py but for now I have just added it to the ./run script.

It is obviously going to need a bit more fine tuning before it is ready to release but it looks very encouraging on first viewing.
I will have a closer look over the coming few days.

I have created a 'Waterfall' branch on github with the latest version. If you make any changes let me know or create a pull request and I will include them.

Thanks,

Colin.

M0DTS
Posts: 684
Joined: Sun Feb 24, 2008 9:03 pm

Re: Possible enhancements / wishlist

Post by M0DTS » Thu Apr 30, 2020 2:38 pm

Ok great.

Yes i must have sent a 'test' version of the gnuradio script with different filename.
Not the neatest of code as always but it works, i'll try harder ;-)

I've put 2x pull request in on guithub, first time i've ever done that!
Fix to master and waterfall branch for a couple of tuning issues.
Added Reference Level adjust setting to the waterfall branch.

Another thing i notice is after some time in operation the latency increases to maybe 0.5 seconds (i am using on network mind), guess this could be due to differing pluto and sound card clocks, not sure what the solution is there...

73
Rob

g4eml
Posts: 752
Joined: Thu Apr 26, 2018 9:36 am

Re: Possible enhancements / wishlist

Post by g4eml » Thu Apr 30, 2020 5:15 pm

Hi Rob,

I have also made some changes to the github branch. I will attempt to merge yours and mine later.

With the extra workload of the waterfall display I have reduced the GUI iteration rate from 1000/sec to 100/sec to give it more time to process the data. That doesn't make much difference to anything else. The only reason I noticed the problem was the dot keyer was running slowly.

I also think the latency drift is due to the clock differences. It happens even with the smaller buffers.

73
Colin.

CU2ED
Posts: 26
Joined: Thu Jan 17, 2019 11:30 am

Re: Possible enhancements / wishlist

Post by CU2ED » Fri May 01, 2020 2:42 pm

Hello all,

this is a great project, already have my pluto working by ethernet, I'm using at the moment the waterfall version ...
I did a small test on QO-100 SAT, TX and RX and it works very well (with the right TX/RX offset of course), it will be great if we can have RIT adjust on SSB it could be something identical to the volume like RIT+ and RIT- and on the up the number in Hz(-,+), there's space on the left side of the screen, we can also have on the SET menu the RIT parameters like 100/10/1 Hz steps choice.

I also detected some problems at least with this version like it starts on the last band I used but I have no signal, as soon I change the band I have signal, the same with volume I have changed to lower value but it always starts with the default value, again if I change 1 unit of volume I have the right level, this is also true for the MIC gain, I didn't try the no waterfall version ... anyway, I know this is a very beta project ...

73

Jacinto
CU2ED

g4eml
Posts: 752
Joined: Thu Apr 26, 2018 9:36 am

Re: Possible enhancements / wishlist

Post by g4eml » Fri May 01, 2020 6:00 pm

Hello Jacinto,

The Waterfall version is now the Master.

The problem with no signal on first use has now been fixed. I saw this yesterday and have been working on it today.
It was because for some reason the Pluto frequency set doesn't work the first time. I now set it twice during startup.

I have not seen your problem with the volume and mic gain. These are working OK for me.
Note that the settings are only saved when you change bands or when you select the set menu.
Maybe you changed the volume and it did not get saved.

I do have RIT on my list. I will add that soon. I think it will be a touch button on the screen and then adjust using the tuning knob. I will probably change the way the volume and squelch work to be the same.

73
Colin.

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