29MHz trans Atlantic DX...

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K0ZAK
Posts: 29
Joined: Thu Apr 29, 2021 3:49 pm

Re: 29MHz trans Atlantic DX...

Post by K0ZAK » Wed Nov 16, 2022 5:37 pm

I use a digital clock in OSB keyed over my video as well as other pertinent info (callsign, dvb specs, freq) plus I also found a great video of a full screen analog clock with a second hand that works well when tweaking my low level signals into our repeater. It helps a lot when trying to eliminate freeze framing while tweaking my settings.

Back to 29 Mhz now. I have now figured out how to use SDRAngel enough to be able to successfully decode DVB-S in my shack transmitted from my Pluto on UHF and 6 meters. The Pluto won't go down to 29Mhz so I can't confirm I've got everything set up correctly for 29.150, but it is just a change in frequency, so things should work. I've also set up the Zello app with the 29Mhz Digital Television chat, so should be good to go for further testing with signals from across the pond.

John Kozak; K0ZAK

radiogareth
Posts: 1371
Joined: Wed Jan 06, 2016 9:46 am

Re: 29MHz trans Atlantic DX...

Post by radiogareth » Fri Nov 18, 2022 3:11 pm

Propagation not great this afternoon, I can see my 66ks now and again on http://kiwisdr.k3fef.com:8073 but very multi-pathy. Need to crack the 18ks really but the rest is working. All sorts of strange stuff floating across the band....
Gareth

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

Re: 29MHz trans Atlantic DX...

Post by g0mjw » Fri Nov 18, 2022 7:31 pm

The repeater was strong and clear at times. I called on the Zello channel but no replies so assumed everyone was at work and went back to building a bigger amplifier.

Mike

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

Re: 29MHz trans Atlantic DX...

Post by M0DTS » Fri Nov 18, 2022 10:16 pm

I'll be around most of the weekend for tests.
I'll be on the Zello channel when available.

Rob

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

Re: 29MHz trans Atlantic DX...

Post by M0DTS » Sat Nov 19, 2022 4:18 pm

Sorry I didn't get on today, a DIY job came up that i couldn't get out of...hi
Its a shame as the new york repeater was strong when i left the house at 1pm!

I will be available for tests most of tomorrow (Sunday).

Rob
M0DTS

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

Re: 29MHz trans Atlantic DX...

Post by M0DTS » Sun Nov 20, 2022 11:53 am

Had success getting a signal via the 20Khz kiwisdr in Switzerland this morning.

I made a test on DVB-S and S2.
DVB-S2 - No decode in SDRAngel, constellation plot does not refresh, no lock on modcode at all.
DVB-S - rapid decodes when qsb allows - the best option right now!

I've made an IQ file recording which you could test with in SDRAngel if you want to have a play about.
DVB-S 18Ks 2/3FEC - (80MB) https://www.dropbox.com/s/2v7o5rtowo1vl ... sdriq?dl=1

FOR REFERENCE, DOES NOT DECODE IN SDRAngel: DVB-S2, 18Ks, 2/3FEC - (30MB) https://www.dropbox.com/s/fpsj5ksulehkk ... sdriq?dl=1

Here's a screenshot of the settings in SDRAngel to playback the recording and and decode the DVB-S signal.

Rob
Attachments
SDRAngel_IQ_Playback.jpg
SDRAngel_IQ_Playback.jpg (336.64 KiB) Viewed 3957 times

radiogareth
Posts: 1371
Joined: Wed Jan 06, 2016 9:46 am

Re: 29MHz trans Atlantic DX...

Post by radiogareth » Sun Nov 20, 2022 7:04 pm

Excellent Rob, that decodes in my SDRAngel too now so I know my settings are good.
Thanks to Mike for help with sorting out the TX stream settings around FFMPEG ect I now have a shack based RF decode using 18ks :-)
Probably won't be on much tomorrow as have a SK funeral to attend, but now 'good to go' with TX & RX :-)
Gareth

K0ZAK
Posts: 29
Joined: Thu Apr 29, 2021 3:49 pm

Re: 29MHz trans Atlantic DX...

Post by K0ZAK » Sun Nov 20, 2022 8:59 pm

I also got the file to decode and the clock on the video incrementing, so I must be doing something right. Looking forward to better band conditions.
John Kozak; K0ZAK

pabr
Posts: 14
Joined: Fri Jan 08, 2016 12:07 pm

Re: 29MHz trans Atlantic DX...

Post by pabr » Mon Nov 21, 2022 1:24 pm

Hello Rob, thank you for posting the IQ recording of DVB-S2 over HF. I had a look and it seems that either your spectrum is inverted or I am not reading the sdriq file format correctly. Anyway, after tweaking leandvb a little I got enough TS to decode this. To make things easier I'd recommend enabling pilots and transmitting short frame.
s2.png
s2.png (29.91 KiB) Viewed 3735 times
F4DAV

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

Re: 29MHz trans Atlantic DX...

Post by M0DTS » Mon Nov 21, 2022 2:37 pm

Thanks!
The IQ file is recorded from a kiwisdr, in SDRAngel there's the option to swap the L/R audio input so that will explain the inversion.
I'll try with pilots and short frame etc and see what happens!

Cheers
Rob

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