Interference when using Wireless Laptop near TV (1 Viewer)

[robbo100]

Hi

This is a slightly random question, but I have recently noticed that my HTPC (single seat) seems to drop frames / stutter when I am using my Macbook with my new Netgear wireless N router (my HTPC is connected to the same router via 1000 Mbps wired connection). The interference is at it's worst when the data transfer through the wireless connection is highest. I have only had the new wireless N router for about 6 weeks but noticed the problem since installing 1.1.0 RC1 (3 weeks ago)

If I connect the Macbook to the router via a 1000 Mbps wired connection, then there are no problems at all, but if I connect using wireless N, I get the problem.

My HTPC is connected to my Amp (using about 3 m cable length) via HDMI and SPDIF (SPDIF through separate cable) and the Amp connected to the TV using just an HDMI cable.

So, why would this problem be bad on a wireless connection but not a wired connection. Is there anything I can do to investigate it? I even thought it might be ElectroMagnetic Interference, but surely that would be unlikely. I doubt EMI would effect the PC itself and surely any interference in the cables would not manifest itself as frame drops, but more like general interference????

Has anyone else ever seen anything like this??

Thanks

Rob



MediaPortal Version: 1.1.0.0 RC1
MediaPortal Skin: X-Factor
Windows Version: XP SP3
CPU Type: Intel E7400
HDD: 700 GB on 2 drives (3 volumes) locally with 1GB FreeNAS
Memory: 2 GB DDR2
Motherboard: Gigabyte GA-EP41-UD3L
Video Card: NVIDIA 9400GT
Video Card Driver: NVIDIA Latest
Sound Card: Onboard REALTEK
Sound Card AC3: Coaxial Out
Sound Card Driver: Latest
1. TV Card: Pinnacle 300i
1. TV Card Type: DVB-T
1. TV Card Driver: Latest
2. TV Card: Compro Videomate S350
2. TV Card Type: DVB-S
2. TV Card Driver: Latest
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec: Cyberlink 9
MPEG2 Audio Codec: ffdshow
h.264 Video Codec: Cyberlink 9
Satelite/CableTV Provider: UK Freesat
HTPC Case:
Cooling:
Power Supply:
Remote: Cyberlink
TV: Toshiba (not sure of model will check later but 32" and about 3 years old)
TV - HTPC Connection: HDMI

 

[Paranoid Delusion]

Does sound like the wireless activity is feeding back through the router.

What I would try, change WLAN frequency 1 through to 13 and see if any one makes a difference, reboot router usually required, don't do this with pending recordings.

Last resort try the MSLoopback adapter, as you are using singleseat, will try and update instructions to include MySQL5.1 today.

 

[robbo100]

I have tried a couple of different channels, but no luck.

I might try setting the router to wireless G only to see if that make a difference.

I will try later tonight.

Thanks

Rob

 

[winterescape]

Hmmmmmm…. the HTPC doesn’t have any wireless cards or Bluetooth transceiver does it? Even if not being used, disable them, and see what happens… Basically any radio transceiver…
In XP use hardware manager and select the device and select disable
Looking at your hardware do any of the tuners have RF interface for remote? Try disabling them and see if anything changes.
Pinnacle 300i
DVB-T
Compro Videomate S350
DVB-S

By the way... if you look at this picture of the wi-fi spectrum it becomes clear why you only need to try channels 1,6, or 11

http://en.wikipedia.org/wiki/File:2.4_GHz_Wi-Fi_channels_(802.11b,g_WLAN).svg

 

[robbo100]

I have a little more information on this now.

It seems that it even happens if I am using PDVD to watch a Blueray disc.

With this in mind, it would seem to be a pure EMI issue. I will do some more investigation over the next couple of days and see if I can characterise what is going on.

I suppose it could be and EMI issue with my Denon AV Amp even???

P.S. I don't have any wireless systems on my HTPC and none of the cards use an RF remote.

Rob

 

[robbo100]

Well I have done some more experimentation, and it definitely seems to NOT be EMI problems and must be network interference.

I have connected the HTPC to a standalone network switch and the problem has gone away.

With the HTPC connected to the main router, I have tried different wireless settings (using g only, different channels etc etc) and nothing has fixed the problem.

I can only assume that this is a problem with my new router (Netgear DGN3500). Hopefully there will be a fix out soon as they usually give an upgrade to the early firmware after release.

Unless anyone has any other ideas? - p.s. if I use the loopback, will my normal network access continue to operate? p.p.s. why would this affect videos in PDVD???

Thanks.

Robbo100

 

[Paranoid Delusion]

Unless anyone has any other ideas? - p.s. if I use the loopback, will my normal network access continue to operate? p.p.s. why would this affect videos in PDVD???/QUOTE]

The loopback adapter is only of use for singleseat setup, it does not affect your ability to access the internet, or for MP plugins to get their goodies from the net

 

[robbo100]

Thanks PD,

Also, just to be absolutely sure, can you confirm that I will still be able to allow MP to access my NAS? - I am pretty sure the answer is yes, but just to make sure.

I have no idea why my wireless laptop is causing this problem, the HTPC is connected wired to the router, so the wireless connection must be sending some unwanted packets to the other PC for some reason.

I may put wireshark on my HTPC and see if I can identify what is going on.

Rob

 

[robbo100]

PD et al.

I have done two screen graps from wireshark which shows the type of network activity with the Macbook pluged into a wired connection, vs the Macbook connected through wireless N (both wired and wirelss go direct to the same router). Screen grabs attached.

Clearly it can be seen that with wireless N in use, there is a massive amount of nasty network traffic from 109.168.1.3 (the Macbook IP address, with .2 being the HTPC IP address).

Can anyone suggest what might be causing this????

Robbo100

 

[Furetto]

Could you save and post the actual logs. I work in networking and have a few colleagues that work with Macs. With the actual files, we can load them in Wireshark ourselves and try to understand.