[mythtv-users] DVB-S All Existing Transports Out of Range

[Nick Morrott]

2009/12/25 belcampo <belcampo at zonnet.nl>:
> Nick Morrott wrote:
>>
>> 2009/12/24 Charles Mason <charlie.mas at gmail.com>:
>>>
>>> Hi all,
>>>
>>> I have a uk based Myth TV dedicated backend and multiple frontends set
>>> up. I have two DVB-T tunners for Freeview and one DVB-S to pick up the
>>> Freesat channels.
>>>
>>> My DVB-S setup appears to be malfunctioning. If in mythtv-setup I scan
>>> all existing transports, it finds nothing almost instantly. Looking at
>>> dmesg I find that it thinks most of the existing transport frequencies
>>> are out of range. However some of the channels appear to work. I can
>>> successfully make recordings from BBC HD, however zone thriller now
>>> CBS Action seems to have stopped working. I think its moved muiltiplex
>>> according to http://www.lyngsat.com/28east.html. However I can't now
>>> seem to get it to scan for anything.
>>>
>>> The results of the dmesg a shown below.
>>>
>>>  3621.517031] DVB: adapter 1 frontend 0 frequency 11262000 out of
>>> range (177000000..858000000)
>>
>> <snip>
>>
>> Are you sure the DVB-S card has not been detected/configured as a
>> DVB-T card? Those min/max freqs look like terrestrial broadcast
>> frequencies, whilst the frontend freqs being tested appear to be DVB-S
>> muxes.
>
> AFAIR these messages has almost always been the case for DVB-S, these were
> 'only; warnings, didn't stop the working, at least that's for me.

Currently true for (UK, at least) DVB-S configurations (I think
there's a ticket for this issue). However, the frequency range that
the OP gave is not that used for satellite and looks more like UHF
frequencies given in Hz.

On my DVB-S backend, I see messages such as:

2009-12-26 18:09:48.184 DVBChan(2:/dev/dvb/adapter101/frontend0)
Warning: Your frequency setting (11343000) is out of range.
(min/max:950000/2150000)

where the warning is triggered due to the incorrect comparison of the
mux frequency received by the LNB (range for Europe Ku-band dishes
11.45-12.75GHz, expressed in log message in kHz) to the LNB's output
received by the DVB-S tuner (range 950-2150MHz, expressed in log in
kHz).

To get from the former value to the latter for the purposes of
comparison, the value of the local oscillator frequency (LOF) in the
LNB used for tuning to the particular mux is subtracted. Europe
Ku-band LNBs have low and high LOFs of frequencies 9.75GHz and
10.60GHz for input ranges of 11.45-11.70GHz and 12.50-12.75GHz
respectively:

Low LOF:
11.45 - 9.75 = 1.70GHz
11.70 - 9.75 = 1.95GHz

High LOF:
12.50 - 10.60 = 1.90GHz
12.75 - 10.60 = 2.15GHz


Cheers,
Nick

-- 
Nick Morrott

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