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From: Reinhard Nissl <rnissl@gmx.de>
To: linux-media@vger.kernel.org
Subject: STV0299: reading property DTV_FREQUENCY -- what am I expected to get?
Date: Tue, 14 Aug 2012 10:53:53 +0200	[thread overview]
Message-ID: <502A1221.8020804@gmx.de> (raw)

Hi,

it seems that my 9 years old LNBs got some drift over time, as 
tuning takes quite a while until I get a lock. So I thought I 
could compensate this offset by adjusting VDR's diseqc.conf.

Therefore I first hacked some logging into VDR's tuner code to 
read and output the above mentioned property once it got a lock 
after tuning. As VDR's EPG scanner travels over all transponders 
when idle, I get offset values for all transponders and can then 
try to find some average offset to put into diseqc.conf.

So here are several "travel" results for a single transponder 
ordered by Delta:

Sat.	Pol.	Band	Freq (MHz) Set	Freq (MHz) Get	Delta (MHz)
S13,0E	H	H	11938	11930,528	-7,472
S13,0E	H	H	11938	11936,294	-1,706
S13,0E	H	H	11938	11938,917	0,917
S13,0E	H	H	11938	11939,158	1,158
S13,0E	H	H	11938	11939,906	1,906
S13,0E	H	H	11938	11939,965	1,965
S13,0E	H	H	11938	11940,029	2,029
S13,0E	H	H	11938	11940,032	2,032
S13,0E	H	H	11938	11940,103	2,103
S13,0E	H	H	11938	11940,112	2,112
S13,0E	H	H	11938	11940,167	2,167
S13,0E	H	H	11938	11941,736	3,736
S13,0E	H	H	11938	11941,736	3,736
S13,0E	H	H	11938	11941,736	3,736
S13,0E	H	H	11938	11942,412	4,412
S13,0E	H	H	11938	11943,604	5,604
S13,0E	H	H	11938	11943,604	5,604
S13,0E	H	H	11938	11943,604	5,604
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,472	7,472
S13,0E	H	H	11938	11945,777	7,777
S13,0E	H	H	11938	11945,777	7,777
S13,0E	H	H	11938	11945,777	7,777
S13,0E	H	H	11938	11945,777	7,777

I really wonder why Delta varies that much, and there are other 
transponders in the same band which have no larger deltas then 3 MHz.

So is it at all possible to determine LNB drift in that way?

My other device, a STB0899, always reports the set frequency. So 
it seems driver dependent whether it reports the actually locked 
frequency found by the zig-zag-algorithm or just the set 
frequency to tune to.

Thanks in advance for any replies.

Bye.
-- 
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl@gmx.de

             reply	other threads:[~2012-08-14  8:53 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-14  8:53 Reinhard Nissl [this message]
2012-08-14 11:10 ` STV0299: reading property DTV_FREQUENCY -- what am I expected to get? Antti Palosaari
2012-08-14 12:05 ` Manu Abraham
2012-08-14 20:15   ` Reinhard Nissl
2012-08-15 14:41     ` Reinhard Nissl
2012-08-15 22:10     ` Mauro Carvalho Chehab
2012-08-18 12:59       ` Reinhard Nissl

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