Sudden increase in bad recordings

[spotty]

Over the last week or two the number of bad recordings I have been having has gone from 1 in heaps to about 1 in 2.
In all cases the symptoms are the same - the recording tries to playback but has massive pixellation and stuttery playback. In most cases it gives up and stops recoding after a few 100KB.
I have tried using 2 other multiplexers and using VLC for playback, but they all result in a similar scenario.
The strange thing is channel seven news at 4:30pm always records perfectly but seven news at 6:00pm always has problems. Other than this I have not been able to see a pattern in terms of channels or time of recording etc.
I'm at a loss as to where to even start looking - and ideas?

[Anthony]

It sounds like a signal reception problem. I see occasional signal drops with both my over-the-air antenna and my QAM cable setups. It usually only lasts a day or two, and may be due to weather or other service issues.

However, you might want to check all of your cable connections to make sure nothing got bumped loose. I moved my computer a bit to clean a couple of weeks ago, and apparently disturbed one of the connections in the process. I had a couple of bad recordings until I tightened up the connections again.

Anthony

[Graham]

There are trees all around my home. I have had reception problems in May when the leaves appear. A new aerial ... on a long pole ... fixed it. A chainsaw would have been cheaper.

[spotty]

It sounds like a signal reception problem. ....
Anthony

What puzzles me is how I can always rely on seven news at 4:30pm but at 6:00pm its always bad. Also too, bad files are consistently bad all the way through. They don't have better patches and then worse patches at all.
This has been happening for over 2 weeks now despite my attempts to fix it.

Is there any way to check the signal strength reliably that I can do at 4:30 and at 6:00 pm to see if it does change?

[ACTCMS]

You could try the ScanChannelsBDA utility from here. AFAIK it should work with most DVB-T tuners.

[gEd]

Is this analogue or digital shows?

If digital I was wondering if the transmission at 4:30 is a lower bitrate than the 6pm show.
Do you ever defrag your recording disk?

[spotty]

You could try the ScanChannelsBDA utility ....

I'll give it a go.

Is this analogue or digital shows?
If digital I was wondering if the transmission at 4:30 is a lower bitrate than the 6pm show

Digital - same bitrate (both HD)

Do you ever defrag your recording disk?

No - Ill try this too

Thanks

[spotty]

You could try the ScanChannelsBDA utility ....

With scanchannelsbda, at 4:30pm and at 8:30pm I got the same result

for SBS, strength = about -25000, quality = 100
for others, strength = -40000, quality = 100

This was immediatey after Mythbusters was recorded full of errors.
All other recordings were bad (the news at 4:30pm doesnt record on weekends)

I have attached a log from comskip to show the errors in the stream.

[spotty]

The plot thickens - I can't get it to play up when I am watching something but it plays up when its unattended.
I have an episode of VideoHits that I started watching while recording - that section of the file is fine but when I stopped watching the file goes bad.
This explains the 4:30pm news recording well - the kids are watching TV at that time, but not at 6:00pm when it goes bad.
I'm guessing its something to do with the CPU/MB throttling down too low - Just a guess though.
I have recently installed 'MCE standby tool' so perhaps this - or its settings - are influencing the situation.

Any ideas on anything I can do to test or fix the situation?

Sub - does the recording engine do anything to get windows to keep the computer running at full speed while recording?

[sub]

Sub - does the recording engine do anything to get windows to keep the computer running at full speed while recording?

No, this is something the operating system doesnt automatically.