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PostPosted: Thu Oct 15, 2015 2:29 pm 
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Joined: Tue Jan 23, 2007 1:38 pm
Posts: 237
Location: Sweden
Hi all!
I am using Hauppauge single and dual USB tuners and having quality issues with pixellated video and garbled sound. I thought that general reception in the area had gotten worse, so I got myself a new, high quality TV antenna and retuned the tuners. They were all having good reception quality. After less than a week, quality issues started to show up again and it is getting continually worse. It seems that rescanning for channels helps for a while.
This never happened with my old PCI receivers on KM5.5. Has anyone seen anything similar?
Thanks,
/Chris

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LinHES R8.2
BE: AMD64X4, 4GB, Hauppauge usb tuners
FE1: Gigabyte F2A85X-UP4, nVidia GT640
FE2: Gigabyte GA-MA69GM-S2H, AthlonX2 4850E 2.5 GHz, 1GB, ASUS GEFORCE 7200GS 256MB
FE3: Asus Chromebox CN60


Last edited by cahlfors on Fri Nov 13, 2015 2:33 am, edited 1 time in total.


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PostPosted: Sun Oct 18, 2015 5:40 am 
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Joined: Tue Jan 23, 2007 1:38 pm
Posts: 237
Location: Sweden
Further testing has revealed that it is not the rescan that improves things - it is only if I shut down the BE computer and leave it off for a few minutes and then rescan for channels, that I get good reception again. I have also tested connecting the antenna outputs to an ordinary TV set and the picture quality there is perfect. It is like the tuners are drifting or something?

Thanks,
/Chris

_________________
LinHES R8.2
BE: AMD64X4, 4GB, Hauppauge usb tuners
FE1: Gigabyte F2A85X-UP4, nVidia GT640
FE2: Gigabyte GA-MA69GM-S2H, AthlonX2 4850E 2.5 GHz, 1GB, ASUS GEFORCE 7200GS 256MB
FE3: Asus Chromebox CN60


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PostPosted: Mon Oct 19, 2015 9:37 pm 
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Joined: Tue Aug 15, 2006 11:14 am
Posts: 1198
Location: Orlando FL
I have no concrete idea of what's going on. Here are just some top of my head ideas since no one else has responded.
Maybe the chip in the USB dongle is getting too hot and the reboot cools it off?
Are you constantly recording live TV or are you doing EIT scans that would keep the tuner awake?
Maybe there is some sort of a charge building up while the computer is running. How is the computer plugged in, where is it grounded?
How is coax antenna cable grounded?
Is it run through a UPS?
Is anything else hooked up to the Coax line?
How are you splitting the signal?

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PostPosted: Wed Oct 21, 2015 12:30 pm 
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Joined: Tue Jan 23, 2007 1:38 pm
Posts: 237
Location: Sweden
Thanks for reaching out to help!

1 Heat. The dongles are cool to the touch. Cold starting + rescanning keeps things in good order for several days or more.
2 Live TV/EIT scans. Live TV usually has very choppy performance, so I use that very little. I will check that EIT scanning is turned off on all receivers!
3 Static electricity. The computer is rack mounted and connected to a grounded wall outlet.
4 Antenna cable. Hm. Two of the coax lines from the splitter are connected to PCI receivers that no longer seem to work and are thus grounded via the computer case. But then again, connecting an ordinary TV set produces perfect picture.
5 UPS. Yes.
6 Other connected equipment. Only LinHES receivers are connected to the coax lines. Oh, and the antenna, of course.
7 Splitter. A six way quality splitter from Triax is being used. It is spec:ed as 1-1000 MHz

This is all about DVB-T.

Thanks,
/Chris

_________________
LinHES R8.2
BE: AMD64X4, 4GB, Hauppauge usb tuners
FE1: Gigabyte F2A85X-UP4, nVidia GT640
FE2: Gigabyte GA-MA69GM-S2H, AthlonX2 4850E 2.5 GHz, 1GB, ASUS GEFORCE 7200GS 256MB
FE3: Asus Chromebox CN60


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PostPosted: Thu Oct 22, 2015 7:13 am 
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Joined: Tue Aug 15, 2006 11:14 am
Posts: 1198
Location: Orlando FL
I had to stop using my PCI tuner I was loosing signal on other tuners from computer noise. It didn't do that when it was new.

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PostPosted: Sun Oct 25, 2015 2:41 pm 
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Joined: Mon Apr 10, 2006 3:48 pm
Posts: 892
Location: Lexington, Ky
You could try this. Might be worth a try,
Also on the same site site is this thread.


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PostPosted: Sun Oct 25, 2015 8:16 pm 
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Joined: Tue Aug 15, 2006 11:14 am
Posts: 1198
Location: Orlando FL
try moving your USB tuner away from the electromagnetically noisy PC with an extension cable or a hub.

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PostPosted: Wed Oct 28, 2015 10:42 am 
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Joined: Tue Jan 23, 2007 1:38 pm
Posts: 237
Location: Sweden
Thanks for the suggestions!

The odd thing here is that quality deteriorates over time. I just powered off the system again and let it sit. I read somewhere that USB tuners are re-initialized when left unpowered for some minutes. The image quality now is perfect on all receivers. We will see how long that lasts. This time I did not rescan for channels. Next experiment would be to unplug the tuners and leave unpowered for a while and then putting them back and see if quality has changed.

My USB tuners are all a little too big to fit side by side directly on the chassis, so hang in a usb cable of 0,5-1 m. I unplugged the PCI tuners from the splitter before powering off. It had no immediate effect, but after restart, live TV plays better than before. Maybe just a lucky shot - it has been a bit arbitrary historically. We will see if this made a consistent improvement. Anyway, the splitter (nor the coax, of course) is no longer grounded.

The hunt continues...

Thanks all,
/Chris

_________________
LinHES R8.2
BE: AMD64X4, 4GB, Hauppauge usb tuners
FE1: Gigabyte F2A85X-UP4, nVidia GT640
FE2: Gigabyte GA-MA69GM-S2H, AthlonX2 4850E 2.5 GHz, 1GB, ASUS GEFORCE 7200GS 256MB
FE3: Asus Chromebox CN60


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PostPosted: Wed Oct 28, 2015 10:11 pm 
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Joined: Tue Aug 15, 2006 11:14 am
Posts: 1198
Location: Orlando FL
Probably should be grounded especially if your antenna is anywhere near lightning.

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PostPosted: Thu Oct 29, 2015 7:11 am 
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Joined: Mon Apr 10, 2006 3:48 pm
Posts: 892
Location: Lexington, Ky
You'll want to place your usb turners as far as possible away from your computer case.


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PostPosted: Thu Oct 29, 2015 3:06 pm 
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Joined: Tue Jan 23, 2007 1:38 pm
Posts: 237
Location: Sweden
OK, will try to increase the distance. Would it be possible to connect them to a hub to simplify wiring?

Thanks,
/Chris

_________________
LinHES R8.2
BE: AMD64X4, 4GB, Hauppauge usb tuners
FE1: Gigabyte F2A85X-UP4, nVidia GT640
FE2: Gigabyte GA-MA69GM-S2H, AthlonX2 4850E 2.5 GHz, 1GB, ASUS GEFORCE 7200GS 256MB
FE3: Asus Chromebox CN60


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PostPosted: Thu Oct 29, 2015 3:07 pm 
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Joined: Mon Apr 10, 2006 3:48 pm
Posts: 892
Location: Lexington, Ky
Don't see why not.


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PostPosted: Wed Nov 11, 2015 1:32 pm 
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Joined: Tue Jan 23, 2007 1:38 pm
Posts: 237
Location: Sweden
Disconnecting the PCI tuners fixed the problem! :D

Things have now been stable for long enough that this can be said. It is interesting to note that just disconnecting had no effect. I had to poweroff, wait, reboot and then rescan for channels as usual, too.

Thanks for all tips! Since computer noise seems to have been the culprit, I will try to increase the distance between the USB receivers and computer case as well.

/Chris

_________________
LinHES R8.2
BE: AMD64X4, 4GB, Hauppauge usb tuners
FE1: Gigabyte F2A85X-UP4, nVidia GT640
FE2: Gigabyte GA-MA69GM-S2H, AthlonX2 4850E 2.5 GHz, 1GB, ASUS GEFORCE 7200GS 256MB
FE3: Asus Chromebox CN60


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PostPosted: Fri Nov 13, 2015 10:20 am 
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Joined: Tue Aug 15, 2006 11:14 am
Posts: 1198
Location: Orlando FL
Glad to hear it worked. :-)
Wireless signals and electronic noise are pretty much black magic. Some people claim that they understand whats going on, those people are wrong.

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