Compatiblity DVB-T2 1.7MHz

Discussion about the Knucker DVB-T Tuner DVB-T Receive Software. See also https://wiki.batc.org.uk/Knucker
Patrice
Posts: 31
Joined: Mon Nov 19, 2018 9:49 am

Compatiblity DVB-T2 1.7MHz

Post by Patrice » Sat Aug 28, 2021 2:49 pm

Hello,
I tried to receive the output DVB-T 1.7MHZ repeater of Paris, but does not work.
Configuration: Raspi 4 and Ryde last version.

73's Patrice F1NSU

f1faq
Posts: 52
Joined: Thu May 12, 2016 1:19 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by f1faq » Sat Aug 28, 2021 3:36 pm

Interesting,

I have this question since some time : Must the transmission be DVB-T2 to be received by Knucker with a BW of 1,7Mhz ?
And by extension by all DVB-T2 receivers ?
I tried receiving myself with a BW of 1,7Mhz, but it did not work. (but was Ok at 2Mhz / 4MhZ / etc...)
73 - Christian
F1FAQ

G8GKQ
Site Admin
Posts: 2798
Joined: Sun Mar 22, 2009 1:21 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G8GKQ » Sat Aug 28, 2021 3:55 pm

Hi Patrice and Christian

I have just done some tests across the shack and 1.7 MHz DVB-T worked for me. So T2 is not required.

Note that the Portsdown/Pluto combination cannot transmit above 1 MHz DVB-T. To generate 1.7 MHz DVB-T you need Portsdown 4 and LimeSDR.

What are the exact parameters (Frequency, FEC, Guard, PIDs) of the Paris repeater?

However, there may be a bug in my update script that has left the old version of the DVB-T receiver there (which did not work on 1.7 MHz due to an error in the manufacturer's example code). To make sure, run this command in Linux:

Code: Select all

cp /home/pi/ryde-build/configs/dvbt/CombiTunerExpress /home/pi/dvbt/CombiTunerExpress
That will ensure that you are using the latest version.

Dave

G8GKQ
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Re: Compatiblity DVB-T2 1.7MHz

Post by G8GKQ » Sat Aug 28, 2021 4:04 pm

And the display. The camera image is upside down, but that is a teaser for something else that I am working on for the Portsdown....
Attachments
DVB-T.jpg
DVB-T.jpg (225.95 KiB) Viewed 8349 times

Patrice
Posts: 31
Joined: Mon Nov 19, 2018 9:49 am

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Sat Aug 28, 2021 4:46 pm

Hi Dave and Christian,
First le 1.7MHz is normalized only for DVB-T2.
The modulator is SR SYSTEM, with encoder H.265.
Parametres are: TX 438.500MHz, BW 1.7MHz, FFT 8k, Modulation 16QAM, Guard interval 1/32, Pilote PP4, constellation rotation, Enable.
With PI Hat tv and Raspi + VLC is perfect.

Regards
Patrice F1NSU

Patrice
Posts: 31
Joined: Mon Nov 19, 2018 9:49 am

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Sat Aug 28, 2021 4:48 pm

I forget, the Nim does not find the signal, like nothing.

Patrice
Posts: 31
Joined: Mon Nov 19, 2018 9:49 am

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Sat Aug 28, 2021 5:00 pm

Dave,
I tried to copy and execute this command "cp /home/pi/ryde-build/configs/dvbt/CombiTunerExpress /home/pi/dvbt/CombiTunerExpress"
but nothing happens

Patrice

G8GKQ
Site Admin
Posts: 2798
Joined: Sun Mar 22, 2009 1:21 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G8GKQ » Sat Aug 28, 2021 5:17 pm

Nothing will happen - but 1700 kHz might work afterwards....

Patrice
Posts: 31
Joined: Mon Nov 19, 2018 9:49 am

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Sun Aug 29, 2021 9:22 am

Not work.

Patrice
Posts: 31
Joined: Mon Nov 19, 2018 9:49 am

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Thu Sep 02, 2021 7:56 am

Dave,
Please find two photos of Knucker searching "438500 KHz at 1.7 MHz BW"

73's Patrice
Attachments
Knucker 1.7MHz BW
Knucker 1.7MHz BW
IMG 2.jpg (837.16 KiB) Viewed 8037 times
Knucker 1.7MHz BW
Knucker 1.7MHz BW
IMG 1.jpg (527.97 KiB) Viewed 8037 times

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