Posts by SWL - markro92

@SWL-ALAIN: can you send me a screenshot?

i want to know the device name from the dropdown box.

The part called 'hwVer' should only be one of these:

That's why i thought that the RSP2Pro wasn't supported.

Maybe RSP2 and RSP2Pro share the same ID.

I only tested with RSP1A, so it's a good thing to hear that they all work.

Hi, it supports only RSP1A and RSP2Duo

Edit: sorry, that wasn't correct, it supports RSP1, RSP1A, RSP2, RSP2Duo.

But not the RSP2Pro. I'll try to add this one, too

why did you turn interpolation off? it's never a good idea

Increasing damping for short periods of time helps, too, while keeping the gain value relatively high. High symbolrates lock faster, because there are more symbols to average out noise, that's how the loop filter works.

Version 2.0.11

Download: http://v.1337team.tk/dvb-s_gui_amsat.zip

Changelog:

• Added Support for Airspy Mini and Airspy R2
• Added Symbolrate presets (with config params)
• Added Symbolrate min/max setting to config
• Made SDRPlay channels A/B selectable via config file
• Made UI style selectable via config file
• Fixed crash on app exit due to double-free
• Fixed FFT Plot display only showing half of the spectrum
• Improved FFT Plot scrolling performance (using ringbuffer instead of memcpy)
• Minor GUI changes (S2 Modcode info)

The next version won't take as long as this one, there are still many smaller things to improve. There will be more changes to the FFT Plot, because in the long run, transponder stats / signal infos will be shown there for each transponder. Maybe left click for moving the spectrum, and right click for selecting transponders. we'll see. For the next smaller update, i'll probably automate things like FEC / Modcode selection and centering / locking.

For now, i'm interested about what the Airspy owners tell me

@IU2KAC: SNR meter is in the TODO list very long now, i'll need to do that soon. Probably in the next version. (2.0.12)

@DB8TF: auto scanning the whole spectrum sounds like a great idea, but i think that will be implemented a bit later, when i also do multi-signal reception. That means in version 2.1.0 which will take a bit time, because it will mostly contain new features instead of fixes.

Edit: i kniow that i didn't implement saving of last used fequency and gain setting. definitely in 2.0.12

DD0KP : can you tell me the exact CPU model? quadcore CPU isn't very specific. I think that this PC will be okay but not great. 4 cores or more is what i recommend, and it should have all features my software needs. But what concerns me, is that they don't even write the exact specifications on their homepage.

Edit: Ok i looked it up, it's a Intel® J3455 QuadCore. It won't work with my software, because it has no support for SSE4.1. I also wouldn't expect very much from this hardware otherwise. That thing isn't worth 400EUR. Maybe the only thing justifying the price s that it's a bundle with keyboard, mouse, monitor.

Do you really need a bundle? This thing also has passive cooling (TDP is 10W), so i don't think that the CPU is great at all. 4GB of RAM also isn't very future proof. We have win10 computes at work and upgraded the RAM capacity to 8GB, and they are also used mainly for office and surfing the internet. Windows also almost eats up 1GB itself.

DK8KW : your observations are correct. Weak signals mean more work for the LDPC Decoder.

@Tony: i already implemented that and it will be in the next version.

Hi, version 2.0.10 ist zurzeit aktuell.

I fixed the DNS entries, now all links should work normally again.

Thanks nico.

i'll try to resolve the DNS issue, in the meanwhile you can use the static IP address of my server.

http://94.130.76.213/dvb-s_gui_amsat.zip

@ik1hgi Tony: i'm glad it works for you now

@ON7NDR: thanks nico, for this great documentation i think that will help new users a lot.

I noticed one weird thing by the way: in the console output, it says QPSK 2/3 and Pilots on, that must be a bug. QPSK never has pilots enabled. Atleast it wouldn't conform tot he standard. I'll look into that. I'll also start to play with two AirSpy samples i received recently.

@DB8TF: currently, there is no obvious was of determining the correct mode.

The only thing you can look for is the IQ Plot. If you choose DVB-S2, and you see almost no symbols flashing up in the constellation, then it's probably DVB-S1. Because Symbols are only being shown when the DVB-S2 start of frame condition (SOF) is detected.

@DB8TF: your settings look good actually, can you try re-checking the carrier recovery box and increase the loop gain to maximum for a short period of time? the signal looked fine to be honest.

Hi, yes, but the signals look very week. they will be hard to lock. but maybe it works

DB8TF : what do you mean with pilot tone? If you mean pilot symbols then no, they wouldn't cause a line in the spectrum, they are scrambled with the PLSC like the data symbols (slots). In DVB-S2, QPSK doesn't have pilots enabled anyway, because there is no need for them.

M0VKK : i can see that you set the wrong modcode. Try QPSK 2/3 for the beacon. The wrong FEC setting also causes the high CPU load. I'll automate that in future versions, but for now it needs to be set manually.

Ok, without attenuator the FFT plot also looks fine. far from overdriving

I would have more information if you captured the whole window in your screenshot.

What exactly goes wrong? timing or carrier lock?

Do you see a circle in the FFT plot? or just noise?

If you just see a circle, you maybe need to increase carrier recovery gain a bit until it locks. When there is no circle, you don't have timing lock and you need to re-adjust the symbolrate because the PLL loop drifted away. You can see that happening when the symbolrate on the bottom of the screen drifts away from the symbolrate you've set with the slider.

M0VKK : do you have a high gain LNB? how does the FFT look like? with and without the attenuator. i almost cant believe that it's overdriving with the gain slider all to the left

@DB8TF: thanks for your feedback. Symbolrate Presets are already done and will be in the next version. Finding the Symbolrate automatically isn't actually that hard to do, i could experiment with that and it will definitely be done, but i think that are more important things right now. Definitely in the TODO list. Same thing for automatically setting modcodes. That would actually be easy to change. Just now, there is no other information passed between the Demodulator and the LDPC worker apart from the XFECFRAME symbols itself. The Modcode information is only being displayed in the console window for now. Saving settings for each input device will definitely be done in next version, as it starts to annoy me, too. I only have the RX channel configurable for the LimeSDR right now (which i should also do for the sdrplay). Because of the LNB stability, yes, "wobbling" LNBs are worst with low symbolrates. The Beacon should work fine, though.

@DJ0MY: yes, i got in touch with him and i'll receive airspy samples soon. After adding Airspy support i'll post a new version where i also fix the issue with UI skins people are having, additional config options, symbolrate presets and LO frequency input (requested by S51KQ). that will be version 2.0.11.

sync_confidence display is unreliable for DVB-S2 by the way and needs fixing as well.

The next major update will be 2.1.0, which will be a partial rewrite and cleanup of the codebase, also adding new features like multi-transponder reception for people who want to watch full duplex QSOs. Also, MER display should make it into version 2.1.0. DVB-S1 settings are quite annoying right now, because they are different from DVB-S2, so they need additional UI elements. The symbol skip button and derotate sliders will disappear in the feature, because finding the right FEC and derotate setting for DVB-S1 can also be done automatically. It's basically trial and error, because DVB-S1 has no frame structure with that information encoded in a header like DVB-S2 has. After that's done however, i should provide some documentation for this software (of course with screenshots and explanation videos as well)

As always, thanks for your feedback and suggestions.

Marcel

DB8TF : Hi, just enter the IP address of the VLC PC. in VLC you use the same URL as always, it's udp://@:8888

@SM4IVE: i dont really know that your question is. do you mean FEC modes for DVB-S1? They are 1/2, 2/3, 3/4, 5/6 and 7/8. DVB-S2 has many more.

Well, QPSK 1/2 is the standard one you can say for DVB-S1, because the native coderate for the Viterbi algorithm is 1/2 (the number of coded bits is twice as many as in the input data) and to do the other coderates, it uses puncturing.

That means that some bits are not transmitted, and on the receiving end, they are just replaced with zero symbols, which just means uncertainty whether a 0 or a 1 has been received. Because when soft-symbol decoding is done, the I and Q amplitudes are the probability that a certain bit has been received (I and Q coding one bit each).

So a symbol in the constellation plot which is very far right on the edge is more likely to be a 1 than a 0, when we look at the in-phase component of the complex symbol.

Puncturing increases the usable datarate, but is more prone to errors.

Depuncturing is done in the receiver before doing viterbi decoding. You use the normal 1/2 Viterbi algorithm on the depunctured data. that's what i got wrong in the beginning so i'll write it here, too