Eliminating wireless interference

[#1]

Ok, so there I was with Routerstats running and monitoring my noise margin. I flipped the TV on and went to the kitchen to put something in the oven. I came back a few minutes later to find that the noise margin had dropped dramatically. Wondering if it was the oven or not, and trying to think of other sources of interference, I switched off the TV. Lo and behold the noise margin shot back up again - it appears the TV (a Panasonic 42" Plasma) was causing a majority of the interference. Now the TV and the router were plugged in quite close to each other, so I switched some plugs around with the TV on and the noise margin improved marginally.
So I decided to relocate the router and telephone so that they're plugged in away from the TV. This seems to have improved things quite well, however flipping on the TV still puts a spike into the system and the noise margin wobbles between 3 and 6dB (whereas before it was going between 0 and 6dB).
Is there any other way to eliminate what seems to be interference coming down the power line? The router is a Netgear DG834Gv3. I've got some ferrite cores lying around and wonder if they're better off placed on the power line or phone line? Is there anything else to try (assuming I'm correct in saying it's power line interference from the TV).

[#2]

It may not be coming down the power lines...... have you got a small battery portable radio receiver?    switch the TV on, and then the portable radio on medium wave.... walk towards the tv screen, and listen to see if there is an increased buzzing sound.....

[#3]

Yeah that's the other option, I guess then the only solution is to increase the distance between the two!

[#4]

Make sure that the power leads are not lying next to each other, or the telephone cable, anywhere along the way....... (mutual conductance )..... are you connecting via wireless? or via cable... to your router?

[#5]

Wireless connection to the router, that's not an issue, my idea was that there was some sort of current being induced in the modem line (hence me moving it, it's got a ferrite core on it too). I'll try and seperate the wires a bit more to see if that improves things, but as the TV is plugged in some 3 or 4m from the router I'm guessing the interference (if it's not wireless) is being passed down the TV power, up into the modem power and interfering there.

[#6]

As you are connected "wireless".... I just wondered if the TV was radiating some "harmonics" and the router was picking them up......

[#7]

Yeah, I'm connected wirelessly on my laptop, although the router also has a hard wire to the recording PC under the TV. I think things are alot better now though, the only spikes I get are when the TV is turned off and on, I'm happily sitting at 5dB SNR (with a bit of variance in the evenings).