[mythtvnz] Tuning FreeView - can't lock transponder and FRONTEND DEVICE busy?

[Steven Ellis]

On Wed, August 8, 2007 9:05 am, Bob wrote:
> On Wednesday 08 August 2007 08:17, Steven Ellis wrote:
>> >> :-(  Don't fret.. just continue. the 8FRONTEND DEVICE: : Device or
>> >> : resource
>> >>
>> >> busy is just a bug in the drivers and actually means you have locke=
d
>> >> into a correct freq.
>> >>
>> >
>> > Thanks, Craig.  That certainly seems to be the case with the FRONTEN=
D
>> > DEVICE error, but... I still don't know why I'm not getting a signal
>> from
>> > the TVNZ transponder.
>> >
>> > # dvbtune -f 1156000 -s 22500 -p h -m 2> /dev/null &
>> >
>> >
>>
>> Ok 12483 H is the TVNZ transponder and you need to make sure the skew =
is
>> correct on your LNB for this one to work. It appears that there is a
>> strong uplink on 12483V which will knock out reception if your skew is
>> wrong.
>
> Just to clarify (and expose my ignorance)... skew is the rotational
> alignment
> of the LNB relative to the rest of the dish, right?

Yes

>>
>> Do you have a sat meter/finder.
>
> Nope.

Any chance you can borrow one as otherwise sorting out the skew can be a
real pain.

>> Ideally you can use 12456H to get the
>> correct skew at which point 12483 should give you a signal.
>
> Ok.  I'm guessing my general dish alignment is good based on the signal=
s
> from
> the Sky/TV3 etc transponders:
> Signal strength: 62208
> SNR: 64401

You don't have a SkyStar2 card so I don't know if the card is reporting
the correct values. On my SkyStar card I get the following for 12483H

vbtune -c 1 -t 1 -f 1883000 -s 22500 -D 0 -p h -m
Using DVB card "ST STV0299 DVB-S"
tuning DVB-S to L-Band:8, Pol:H Srate=3D22500000, 22kHz=3Doff
ERROR setting tone
: Invalid argument
polling....
Getting frontend event
FE_STATUS:
polling....
Getting frontend event
FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI
FE_HAS_SYNC
Bit error rate: 244
Signal strength: 52390
SNR: 51216
FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI
FE_HAS_SYNC
A/V/TT Filters set
Signal=3D51807, Verror=3D0, SNR=3D51213dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D51872, Verror=3D0, SNR=3D51144dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D51812, Verror=3D0, SNR=3D51189dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D52540, Verror=3D0, SNR=3D51135dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D52032, Verror=3D0, SNR=3D51171dB, BlockErrors=3D0, (S|L|C|V|SY|)


And for 12456H I get

mythtv@mythtv:~/dvb$ dvbtune -c 1 -t 1 -f 1946000 -s 22500 -D 0 -p v -m
Using DVB card "ST STV0299 DVB-S"
tuning DVB-S to L-Band:8, Pol:V Srate=3D22500000, 22kHz=3Doff
ERROR setting tone
: Invalid argument
polling....
Getting frontend event
FE_STATUS:
polling....
Getting frontend event
FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI
FE_HAS_SYNC
Bit error rate: 3741
Signal strength: 51298
SNR: 57018
FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI
FE_HAS_SYNC
A/V/TT Filters set
Signal=3D51283, Verror=3D0, SNR=3D56955dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D51810, Verror=3D0, SNR=3D57168dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D51361, Verror=3D0, SNR=3D57291dB, BlockErrors=3D0, (S|L|C|V|SY|)
Signal=3D51340, Verror=3D0, SNR=3D57198dB, BlockErrors=3D0, (S|L|C|V|SY|)


The main thing to note here is that Verror=3D0 for both transponders, whi=
ch
means I have no cross polarity issues.


> So I should be able to scurry up on the roof and rotate the LNB from tw=
o
> extremes until I lock on to 12483 then bisect the angle and tighten the
> screws?  Then verify that I'm getting the other transponders at the sam=
e
> or
> better signal strength.

Using 12483H to get the lock is a real problem due to the uplink on 12483=
V.

Basically use 12456H to get the strongest signal signal and then make sur=
e
that 12456V has no signal (known as cross pol null). Then 12483H should b=
e
ok.




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--------------------------------------------
Steven Ellis - Technical Director
OpenMedia Limited - The Home of myPVR
email   - steven@openmedia.co.nz
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