[mythtv-users] No live tv and not recording

Klaus Becker colonius at free.fr
Wed Mar 14 18:23:57 UTC 2018

Le jeudi 15 mars 2018, 02:17:36 CET Stephen Worthington a écrit :
> Yes, that is a Universal LNB, with two local oscillators.  So the low
> and high frequencies are what you need.  The switch frequency is not
> defined by the LNB - it has to take into account the capabilities of
> your DVB-S2 cards and the highest and lowest frequencies you want to
> receive from your satellites.  The DVB-S2 cards will have a
> specification for the frequency range they support.
> The way it all works is that the frequency of the satellite
> transmitter (TF) gets mixed in the LNB with the local oscillator
> frequency (LOF), and that produces signals at frequencies of TF+LOF
> and TF-LOF on the aerial cable down from the LNB.  The TF+LOF signal
> is a very high frequency that is probably too high to even propagate
> well down the aerial cable, and is so high that your DVB-S2 card will
> not see it either.  The card may have a filter circuit to block it if
> necessary.  The TF-LOF signal is the one the card needs to be able to
> receive.  My TBS 6909 DVB-S2 card can receive 950 - 2150 MHz, and most
> consumer style DVB-S2 cards will have a very similar frequency range.
> So, using those numbers, you need to have TF-LOF in that range, so
> using your low LOF frequency of 9750 MHz, the DVB-S2 card will be able
> to receive from transmitters in the range 10,700 MHz - 11,900 MHz.
> Using your high LOF frequency of 10600 MHz, the card will be able to
> receive from transmitters in the range 11,550 MHz - 12,750 MHz.  There
> is an overlap in the middle, so transmitters in the range 11,550 MHz -
> 11,900 MHz are able to be received using either the low LOF or the
> high LOF.  So the switch frequency where reception changes from using
> the low LOF to the high LOF needs to be set in that overlap range - I
> would suggest having it in the middle at say 11,725 MHz.  The switch
> frequency is used by mythbackend to decide whether to tell the DVB-S2
> card to switch on or off the 22 kHz tone that tells the LNB to switch
> to the high LOF.
> The full frequency range you will be able to receive from is 10,700
> MHz - 12,750 MHz, so I hope that covers everything you want to receive
> from your satellites.

Hi Stephen,

Thanks for all these explanations !

I tried again with

LOF- =  		 9750 MHz
LOF+ = 		10600 MHz
LOF Switch = 	11725 Mhz

No signal for scanning!

And still the message "DVBChan[1](/dev/dvb/adapter0/frontend0): Your frequency 
setting (114000) is out of range. (min/max:925000/2175000)"

But the LOF Switch (11725 Mhz) is not in the middle oh LOF- (9750 Mhz) and LOV
+ (10600 Mhz).

Did I understand you right ?

LOF Switch does'nt depend on LOF- and LOF+ but on the capabilty of the card ?

Iif so, the only problem I have seems to be the above error message about the 
frequency setting.

I have no splitting. My Optex antenna has 2 LNBs but acually I use only one.



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