[mythtv] [mythtv-commits] Ticket #2060: US cable frequency tables incorrect

Michael T. Dean mtdean at thirdcontact.com
Fri Jul 21 19:46:37 UTC 2006


On 07/21/2006 02:06 PM, Daniel Kristjansson wrote:

>On Fri, 2006-07-21 at 13:22 -0400, Michael T. Dean wrote:
>  
>
>>On 07/20/2006 07:48 AM, Daniel Kristjansson wrote:
>>    
>>
>>>On Wed, 2006-07-19 at 12:49 -0400, Michael T. Dean wrote:
>>>      
>>>
...

>>if you saw a 100kHz 
>>difference in IRC, our information sources must have different values.
>>    
>>
>Here's my source: http://www.ipass.net/teara/atv1-frm.html
>  
>

Will compare once I get home.

>>if we modifiy the frequencies by these amounts.  If, in fact, we are 
>>ever off by 62.5kHz (1 tuner step) or more (such as the 100kHz you 
>>mentioned), it's worth fixing the frequencies.
>>    
>>
>There is also rounding/truncation error. We only need to be a little
>off to jump to the next tuner step in either direction.
>  
>

OK.  I'll prepare patches for HRC and IRC to get them closer to exact 
(by rounding) and post them for you to consider after 0.20.

>>Since most cable companies use a positive offset, it's quite possible 
>>that users whose cable companies use a negative offset have needed to 
>>specify a negative finetune for the offset channels (14-16, 25-53, 98, 
>>and 99) to reliably tune those channels.  I would be very interested to 
>>see what channels users have offset and by what amounts.  I'd be happy 
>>to start a thread on the -users list asking for info (since no one who 
>>doesn't have to will have read this far in my message :).  And, if it 
>>turns out that negative finetune values consistently appear for the 
>>affected range of channels, I'll create a patch to add a positive and 
>>negative version of the frequency table.
>>    
>>
>I would be good to get some feedback from users actually using finetune..
>  
>

I'll start a thread asking for the appropriate info.

>>>Perhaps we could just fix the channels referencing the tables?
>>>      
>>>
>>I'm not sure what you mean by this.
>>    
>>
>If we change the channel frequency by 25 kHz, maybe we should make the
>reverse change to any pre-existing the finetuneing in the DB...
>  
>

Oh.  I see, now.  Makes sense.

Mike


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