Gigabit Network Causing RFI

[VK1JA]

G'day all,

I have a network setup throughout the house with cat5 cabling running to most rooms. I've recently found that the 8 port gigabit D-Link switch is causing a lot of RFI on 6m - roughly S5-7 of noise. It doesn't seem to effect any other bands that I know of - yet.

Now a couple of questions for the computer/network savy people. I've only got cat5 cabling through the house, but as the cable runs are short I'm still getting 40-50mbit network speeds. Would cat6 cabling be better shielded thus reducing the noise from the D-Link switch. And secondly, failing the cat6 idea, does anyone know of a 'quiet' 8 port gigabit switch?

If I plug the cables into my belkin router which is only 10/100 there is no noise.

I've alread got ferrite cokes on the dc power going into the gigabit switch but that hasn't helped, I've also tried putting ferrite cokes on all the cat5 cables coming out of the switch but this resulted in very bad network speeds and at times no network connections at all !!

73's

Jayson

[VK5ZD]

Hi

If you can, set everything to operate at 10Mb/s. This should give you a big reduction in QRM from the network. I know this is relatively slow, but it's not really noticeable unless you're transferring large amounts of data between PCs.

73
Iain

[VK2CBL]

I had a similar problem and fixed it with a few ferrite toroids.
Use toriods that are large enough to allow a few turns of the cable.
You may need to do all cables including the power cable.
Jaycar should be able to supply what you need.

[VK1JA]

Thanks for the replies guys,

Iain - going back to 10/100 speeds would kill me, I do transfer a lot of large (5-10gb) files regularly and also stream HD video content throughout the house, so going back to 10/100 isn't an option

VK2CBL - when you say put ferrite toroids on all cables, you mean the cat5 cables as well? When I did this it killed the network... I'll give it another try though. I have a heap of toroids that I can throw on the cables.

Cheers

[VK2CBL]

Yes on the data cables. I should not kill the network.

[VK2CBL]

here is a pix i forgot to upload.

[VK6SIX]

If that was my setup, i would point a suspect finger at the power supply for the giga switch. [or maybe another PS in the system]

Can you try a battery to power the switch as a test?................... even if the power supply seems ok, try a battery.

Also 2 or 3 years ago i published the info below on vkham a few times, may not be your problem but may be useful in future.

graham vk6six/vk6ro

NIC QRM

If you have BIG BIG birdies/tone on certain fixed

freqs on 20 metres at approx

14.090/029/091/151 and 14.213mhz and other various

freqs etc and you use cat5 cable network

and you think it is from your modem... it probably

is not, it is those very dirty 100mb NIC

chips in your NIC in the computer.
To fix it, try changing the speed to 10mb and it

disappears instantly!!

CONTROL PANEL/SYSTEM/DEVICE MANAGER/NETWORK

ADAPTERS... RIGHT CLICK ON NIC,/PROPERTIES/ADVANCED then possibly SPEED/DUPLEX SETTINGS [or similar words]

snoop around to find the 10mb full duplex or similar

setting and change the speed to 10mb

full duplex, apply etc....VOILA! if it was the NIC

the birdies have GONE.

or use wireless LAN and it fixes it as well

providing you have no other cat 5 in the NICS in the

house running at 100mb

[VK6ADF]

if all that does not work, have you thought of trying wireless?

[VK4GHZ]

Is this a problem, not with a specific brand/model of ADSL Router/Switch, but Gigabit LANs in general?

I am about to replace my Netgear ADSL 802.11BG router/switch with a Billion BP7800N 802.11BGN router/switch which features 4x Gigabit ethernet ports.
As the modem itself lives in the shack, it would be a backward step, if Gigabit LANs cause this much crud.

[VK4XA]

I too had a heap of noise from my household network.
Slowing the network down to 10Mb/s got rid of most of the crud but as mentioned in an earlier post video streaming became a problem, but only if 2 or more kids were watching movies at once.
I ended up ditching the wired network entirely and shifting to a wireless network, it was the best decision I could have made, no more noise on the HF-6M bands! (Nowadays I don't give a crap about 2m and up.)
Streaming of videos and file transferring isn't a problem either, I moved the video's to another machine and set it up with a short (3ft) long 10Mb/s wired connection, it does everything it needs to do.

PS. I also ditched my DLink switch / router, it is the noisiest piece of garbage out there.
(I use a Billion ADSL/Modem/Router/Wifi unit to do all the networking stuff, it's a much quieter solution to my rfi issues)

[VK1JA]

Thanks again for all the replies, I had time today to test the network and find out exactly where the noise was coming from, mind you all was fine when I had the server here in the room with me, but once I moved it into another room (server fans were driving me nuts!!) the rfi noise started

I've now reduced the rfi on 6m down to an S2 which I'm happy with.

I've put two ferritte clamps on the cat5 cable coming out of the D-Link switch (with one loop) and another two on the cat5 cable going into the back of the server. As well as that I had to put (this will make you laugh) three large ferritte clamps with 6-7 loops of cable each and another three small clamps on the D-Link plug pack power supply to get the rfi noise on 6m down to an S2.... That's six clamps just on the power supply....

I also put two clamps on the modem/router power supply too, just in case.

As the D-Link power supply is 5v @ 1amp and the modem is 12v @ 1amp I'm considering using a computer psu to run the switch and modem. The switchmode psu out of a computer should be heaps cleaner than these crappy plug packs

One thing I noticed that was very strange - and I hope some one can give a reason for this - when I had the rfi noise down to an S3-4 I noticed that the rfi would go away if I simply put my hand on both the plug packs, simply just touching the plug packs would reduce the rfi. Keep in mind that the plug packs are plastic !!

Any explaination for this?

P.S. my network speed have suffered from this, now down to about 30Mbit per second, but this may be because the cable length is longer and it's still only cat5, not cat5e or cat6. I might grab some cat6 and replace that cable run - one day..

[VK6SIX]

Gday

Ah yes the power supplies should be viewed with extreme suspicion, if possible test using pure battery DC maybe use a 7805 to get the 5 volts needed.

maybe use a ham power supply that has a real transformer, for the tests.

these type of power supplies should never be trusted.

cheers graham

[VK2XAX]

Do your self a favour and replace the PSU with some sort of linear supply. Most modern plug packs are nasty little switched modes that create all sorts of crud. Dont forget that these things are double insulated so even their "earth" is radiating noise.

A PC SMP will generate lots of noise, especially if its not in a box.

regards


Tim