From: Vincent McIntyre <vincent.mcintyre@gmail.com>
To: Eyal Lebedinsky <eyal@eyal.emu.id.au>
Cc: list linux-media <linux-media@vger.kernel.org>
Subject: Re: [progress]: dvb_usb_rtl28xxu not tuning "Leadtek Winfast DTV2000 DS PLUS TV"
Date: Tue, 26 Sep 2017 22:45:11 +1000 [thread overview]
Message-ID: <20170926124508.GA17883@ubuntu.windy> (raw)
In-Reply-To: <678bf4fa-5849-1fb2-adf1-a07458767d9e@eyal.emu.id.au>
On Tue, Sep 26, 2017 at 02:32:26PM +1000, Eyal Lebedinsky wrote:
>
> While the problem persists, I managed to find a way around it for now.
>
> I changed the antenna input.
>
> Originally I used a powered splitter to feed all the tuners, and it worked
> well with the out-of-kernel driver. This driver does not build or work with
> a more modern kernel so I shifted to using dvb_usb_rtl28xxu which fails to
> tune.
>
> The new wiring splits (passive) the antenna in two, feeds one side directly
> to the two "Leadtek Winfast DTV2000 DS PLUS TV" cards (through another passive
> 2-way) and the other side goes to the old powered splitter that feeds a few
> USB tuners.
>
> Now all tuners are happy. It seems that the "Leadtek Winfast DTV2000 DS PLUS TV"
> cannot handle the amplified input while the USB tuners require it.
>
> I hope that there is a way to set a profile in dvb_usb_rtl28xxu to attenuate
> the input to an acceptable level thus unravelling the antenna cables rat-nest.
Glad you had some success.
I did some more rummaging in v4l-utils. It may help you to know about
dvb-fe-tool, which gives information about the frontend device
(eg /dev/dvb/adapter0/frontend0). In particular you can monitor the
s/n as you make changes:
# dvb-fe-tool --femon -a 0 #here doing adapter0/frontend0
It displays info about the signal quality and the carrier/noise (C/N) ratio,
which might help any investigation of where the driver fails to cope as
you change what you are feeding it.
I noticed your dvbv5-scan showed C/N around 20dB but the manpage shows
'good signal' with C/N of 36dB which suggests the device should be
expected to deal with higher signal levels.
Once you figured out the signal level, did a dvbv5-scan work with no
errors? In the example you showed I saw the channels getting 'lock'
but then some kind of error occurred.
Regards
Vince
next prev parent reply other threads:[~2017-09-26 12:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-18 4:26 Urgent: dvb_usb_rtl28xxu not tuning "Leadtek Winfast DTV2000 DS PLUS TV" Eyal Lebedinsky
2017-09-23 12:48 ` f26: " Eyal Lebedinsky
2017-09-24 9:04 ` Vincent McIntyre
2017-09-24 9:42 ` Eyal Lebedinsky
2017-09-25 0:16 ` Eyal Lebedinsky
2017-09-25 13:24 ` Vincent McIntyre
2017-09-25 14:37 ` Eyal Lebedinsky
2017-09-25 15:23 ` Eyal Lebedinsky
2017-09-26 4:30 ` Eyal Lebedinsky
2017-09-26 4:32 ` [progress]: " Eyal Lebedinsky
2017-09-26 12:13 ` Eyal Lebedinsky
2017-09-26 12:45 ` Vincent McIntyre [this message]
2017-09-26 13:17 ` Eyal Lebedinsky
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