[mythtv-users] Mobo recommendations

Yan Seiner yan at seiner.com
Wed Apr 11 15:23:58 UTC 2007


Brian Wood wrote:
> On Apr 11, 2007, at 8:29 AM, Yan Seiner wrote:
>
>   
>> At this point the problem seems to be periodic; recordings are fine
>> during the day but start to flake out in the evening.  I suspect it  
>> has
>> to do with signal strength so I ordered power injectors for my
>> antennas.  We'll see how that goes.
>>
>>     
>
> Although possible, it's not very likely that you are having enough  
> signal level variation from night to day to cause things to "flake  
> out". VHF/UHF signals do not depend on atmospheric layers that change  
> with the sun. Amplifiers might cause more problems than they solve,  
> by creating overloads and distortion products.
>   
I don't have cable; my signals come from 2 directional antennas.  I have 
clear line of sight to the transmitters on one side and almost line of 
sight to the other set.  The antennas are winegard amplified antennas; 
I've been using them without power injectors and they worked fine up 
until last summer.

> The first thing I'd look into is whether the problem is really "night  
> and day" or something else related to it (like perhaps you just  
> record more TV at night, and so statistically are more likely to see  
> problems). Does this happen on more than one channel?
>   
We typically only record one channel (PBS, both analog and digital)...  
The recordings are OK until 5:30 PM, at which point they go to crap - 
both analog and digital go to crap.  That's pretty weird.  Also, while I 
am using the same cabling, it is routed differently, so it's possible 
(thinking out loud) that we're turning on an appliance that's hosing the 
signal.

During the summer the two schools across the street installed about 
$500,000 of wifi and other hi-tech gear. They've taken over the entire 
802.11 spectrum and knocked my wifi network completely off-line during 
school hours.

Unfortunately I can't be certain if that's related; we had some 
construction at the house and my old server died last summer partly as a 
result of the electrical work.  Because of the construction, I wasn't 
able to get Myth recording until just now.

> It could even be something like your AC line voltage dropping when  
> everyone in your area turns on their lights, TV sets and home  
> computers. If your power supply is at all marginal even a slight drop  
> in AC voltage could cause the PSU's output to go out of regulation.  
> Most "flaky" computer problems are caused by power supplies in my  
> experience.
>   
All of the equipment is new. I am not discounting the possibility, but I 
spent a good bit of money on fairly good stuff to reduce the chances of 
that...

> Obviously I can't diagnose the problem from here, but I'd put "signal  
> level" way down on the list of possibilities.
>   

Well, it's costing me $30 to get the power injectors and new splitters; 
that's cheap enough for a look-see.  :-)

More next week when that stuff gets here.

--Yan


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