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

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Thu Sep 02, 2021 7:57 am

I forget, the signal is 20dB over noise.

G4GUO
Posts: 726
Joined: Tue Feb 16, 2010 12:51 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G4GUO » Thu Sep 02, 2021 8:40 am

Dave,

Have you tried it with the 8K mode?
I found the transmitted signal had to be much more 'accurate' with 8K than with 2K on a Knucker.
The Paris repeater appears to be using 8K 64QAM.

- Charles
G8GKQ wrote:
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.

Dave

G8GKQ
Site Admin
Posts: 2794
Joined: Sun Mar 22, 2009 1:21 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G8GKQ » Fri Sep 03, 2021 9:15 am

Hi Charles

I have not tried 8K 1.7 MHz DVB-T (no means to generate it), only 2K. I know that 8K 8MHz DVB-T2 from a broadcast MUX does work (but challenges the RPi 4 to play smoothly).

Patrice - have you tried slight frequency adjustments either side of the nominal frequency?

Dave

g0mjw
Posts: 2311
Joined: Sat Sep 20, 2014 9:15 am

Re: Compatiblity DVB-T2 1.7MHz

Post by g0mjw » Fri Sep 03, 2021 10:49 am

With off-air signals it is extremely important to have a good band pass filter for 70cms in place or the tuner will see all sorts of other signals that may upset it. I know it is designed for TV use but the TV channels are specifically arranged to minimise the images etc. On 70cms not so.

Mike

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

Re: Compatiblity DVB-T2 1.7MHz

Post by f1faq » Fri Sep 03, 2021 1:31 pm

Hello,

Got mine working at 1.7M bandwith now
Receiver : Knucker (just built)
Transmitter : Portsdown 4 + Lime (FFT 2K / QPSK / FEC 5/6 / Gard 1/32)
Remark : replaced the Lime by Pluto and did not work (Too much BW for Pluto or wrong F5OEO FW ? - was Beta For the Brave)
73 - Christian
F1FAQ

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

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Fri Sep 03, 2021 2:32 pm

Hi Dave, Hi Charles,
I tried to scanne frequency from 438.200 to 438.700 MHz but nothing.
I tried 2K instead 8K nothing,
I switch the repeater 1.7 to 5MHz and...it worked.

73's Patrice

G4GUO
Posts: 726
Joined: Tue Feb 16, 2010 12:51 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G4GUO » Fri Sep 03, 2021 4:20 pm

Hello Patrice,

It sounds like you must still have the wrong version of the code installed.
I know Dave has already instructed you on how to upgrade it but in the first version there was a mistake in a table
that programs the internal clocking in the NIM (the mistake was only for the 1.7 MHz entry).

Basically the only change to get different bandwidths is that one table so if it works at very low bandwidths it should also
work at 1.7 MHz (unless the table entry is wrong)

- Charles

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

Re: Compatiblity DVB-T2 1.7MHz

Post by Patrice » Sat Sep 04, 2021 8:45 am

Hi Charles,
Could you confirm the code as follow is correct ?
cp /home/pi/ryde-build/configs/dvbt/CombiTunerExpress /home/pi/dvbt/CombiTunerExpress

Patrice

G8GKQ
Site Admin
Posts: 2794
Joined: Sun Mar 22, 2009 1:21 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G8GKQ » Sat Sep 04, 2021 8:52 am

Hi Patrice

I'll get back to you later today with some tests to check that you have the correct version for 1.7 MHz.

Dave

G4GUO
Posts: 726
Joined: Tue Feb 16, 2010 12:51 pm

Re: Compatiblity DVB-T2 1.7MHz

Post by G4GUO » Sat Sep 04, 2021 11:00 am

Sorry Patrice I can't as I am not using Ryde software with mine.

I just have the manufacturer's SDK which I run on a regular Linux x86 PC.

- Charles
Patrice wrote:
Sat Sep 04, 2021 8:45 am
Hi Charles,
Could you confirm the code as follow is correct ?
cp /home/pi/ryde-build/configs/dvbt/CombiTunerExpress /home/pi/dvbt/CombiTunerExpress

Patrice

Post Reply

Return to “The Knucker DVB-T Tuner and Receive Software”