NBW

I have a TV aerial cable coming down into the room next to the PC, where it plugs into a mains-powered signal amplifier, and then into a distribution amplifier, also mains-powered.

The TV signal is distributed to a VCR in the same room, a FM radio, a TV card in the PC, and then on downstairs to a TV in the kitchen.

Problem is interference from the PC. With it off, all channels can be received OK, but as soon as the PC is on, the RFI generated overwhelms BBC2 and Channel 5, the weakest signals.

Question is, is it worth connecting the aerial amps to the mains via a RFI filter, or is the interference more likely to be EM radiation? The aerial connections are via the plastic-shrouded plugs supplied with the amps, so would it be worth swopping these, or at least changing the plugs for metal ones?

I tried earthing the aerial wall socket (which is a fully-screened type), but this made no difference.

Any suggestions?

Cheers
Tim

NBW

It's a Hauppauge Win Tv Go!

Signal is perfect with PC switched off, so I can't see that it's a problem with the aerial amps....

Cheers
Tim

AndyC_772

iTrader: (2)

I'd guess that the interference is getting from your PC to the TV signal through the TV card. Have you tried switching the PC on but with the aerial unplugged from the TV card? I'd bet several beers that that would fix the problem. Of course, that means your TV card is now useless.

It's very unlikely to be mains borne - PCs need to have pretty comprehensive filtering on their power supplies to comply with conducted emissions regulations. I wouldn't waste any time or money replacing your plugs or filtering the power supplies to the aerials either.

Have you confirmed that you really need both amplifiers? In my own setup, also a poor signal area, I actually achieved better results with a single 4-way distribution amplifier. If you have the option to put the first amplifier physically close to the aerial then that might help too - the signal will be attenuated by the cable between aerial and amplifier, which makes your setup more sensitive to noise.

You may need (as David suggested) to filter the cable carrying the signal to your PC card. A bandpass filter is one option, although it's just possible that a simple attenuator or even just a ferrite clamped on the cable will help. You could even try moving your PC card to another slot - try and get it as far from your CPU and DRAM as possible.

Let me know how you get on,

Andy.

NBW

I get the interference even without the PC connect to the aerial, hence my guess that the RFI was possibly mains borne. the PC is physically close to the aerial amps.

Pretty certain I need both amps though, there is a definite improvement with both amps in place.

Good idea to move the first amp up close to the aerial, might give that a go at the weekend.

Cheers
Tim

David_Wallis

ooo dear.. Like said above there should be pretty good filtering... Have you got the lid on the pc.... if there is a earth lead coming off the power supply is it connected to the case?

Have you got the lid on the pc??

try coiling all cables in a figure of eight, not in a loop.

Try borrowing another PSU...

Could also try wrapping the mains cable around a ferrite bead as also suggested above...

David

David_Wallis

What sort of tv card is it?

Could also try a bandpass filter on it..

Also try with out each amplifier, as the signal may be too strong.

David


[Edited by David_Wallis - 5/12/2002 6:42:03 PM]