Desktop PC Interrupts TV Reception

mistro

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Mar 2, 2014
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I wasn't sure where to post this so I chose Systems since my issue is related to my desktop.

My wife and I are using a converter box to watch TV in a limited space. We get the channels that matter the most but channel 7 does not play nice when I'm on my PC working. I discovered this issue when I was watching the news one morning and as soon as I powered on the PC, channel 7 just stopped working. If I let the PC settle and don't launch any programs or do work on a 3D model for example, the TV channel will become stable until I start working again. It's driving me nuts because I have to choose between letting my wife watch her shows or getting some work done. And note, its only channel 7 and I think channel 11 that behaves this way.

Does anyone know if this would be caused by the electrical grid or is it some other kind of interference? I even tried plugging the PC into an outlet far from the TV and still the same issue occurred.

I have a PC tower with a 850w power supply, Gigabyte x79-UP4 motherboard, i7-4930k cpu, NVidia GTX760 2gb video card, ssd internal hard drive and 2 external hard drives.
 
I'm assuming your using an antenna to watch TV?
It can be very difficult, frustrating and sometimes nearly impossible to stop radio frequency interference.
Does your desktop use wireless or is it connected to your router and/or modem with a cable?
Wireless anything could be a potential cause or something that makes it worse.
Try adjusting the antenna to get better signal OR just get a different one. I read that the Mohu Leaf is one of the best you can buy.
Is your antenna amplified? If it is, will it work without being powered (as a passive antenna)? If it will, disconnect the power and see if there's a difference.
 
Is the antenna cable (or the antenna itself) physically close to the computer? My mate had a similar issue when his antenna cable ran right past the computer. Simply moving the cable as far as possible from the computer might solve the issue. Those cables are super-sensitive to noise if you're running with marginal signal strength.

Bit of al foil around the antenna cable might reduce noise a little to? It's a long shot but you never know! http://www.rcgroups.com/forums/showthread.php?t=1541290
 
I have a network cable connected to my Ethernet port for the internet. No wireless. My antenna is amplified and plugged in. I will try with it plugged out. It's not near the computer though. The modem is by the antenna. But internet activity don't interrupt the signal. I think it's when the CPU is actively computing. I actually been thinking of trying to use foil as some kind of barrier but don't know how. What kind of barrier is affective against radio frequency interference?
 
I believe standard aluminium foil will block some external RF noise, though you may need to have the foil grounded (in contact with the metal frame of the cable) for it work.

Most those cables are already shielded though, so the additional foil layer may have little effect.

I really don't claim to be an expert on this, it was just a thought as something worth trying... only take you a minute or two to have an answer about whether it makes a difference.

However, I'd find it extremely difficult to believe the computer could generate sufficient noise to effect your signal unless it's physically close to the cable or antenna... so your issue as you describe it doesn't really fit my (already fairly unlikely) solution.

I suppose you could answer the distance question by connecting the computer with an extension cable and moving it as far from the cable+antenna+tv as possible (as a test). If that solves the issue then you can try to find a way to reduce the RF noise from the computer.

It's hard to believe it is the modem (I agree you would then expect to lose signal only when the internet is in use), but for sure worth trying the computer on with modem unplugged to see if that makes a difference too.
 
I have exactly the same problem, with channel 7. The tower is 5 meters from the digital TV and about 6-7 meters directly blow the antenna. The tower is connected via cable to the modem. We have a laptop connected to the modem via wi fi, around 3 meters from the tower. Both the tower and the laptop access power from a twin point in the wall.. As soon as we boot the tower computer we loose the signal on channel 7. The laptop doesn't affect the TV. I've replaced the antenna, dialed the signal in with a signal finder, cleaned all posts. I'm stuffed. Can't figure it out. This is a new tower. I wonder if the power source in the tower is the cause?



 
For the record, I had a very similar case. I have my TV connected to my PC via HDMI cable in the bedroom. When I turned the PC on, the first few channels on the TV would vanish altogether, and others would be affected by heavy interference. As soon as the PC powered off the display due to inactivity, the problem went away.
I solved it by buying a shielded antenna cable to replace the basic old white one I had.

Then I bought a new TV which went against the other side of the same wall in the living room, fairly close to the PC. I was astonished to see exactly the same effect. I've bought another shield cable, but I intend to do some experiments with tin foil to see if I can narrow down the cause a bit more.

Buying shielded HDMI cables didn't help at all.