Wireless Encryption

Prisoner6409

Thanks to a few of the guys here I have successfully set up a wireless internet connection using the Eircom(Netopia 2247NWG) modem and a Netgear W111T wireless adapter. I have set this up using WEP encryption and everything is fine with the adapter to modem signal strength at V. Good to Excellent. As some ppl have reccommended WPA over WEP and as WPA is generally recognised as better security I changed the encryption I'm using to WPA-PSK. However when I do this the signal strength goes from V.Good to Excellent to Good or Low. I would not have expected the encryption status to have any effect on the signal strength. Any ideas why this might be happening.

Krusty_Clown

Nope!

Are you sure it's not coincidental? i.e. Interference from another source, say for example: a microwave, wireless alarm, other wireless network?

If youy switch back to WEP, does the signal strength go back to Vgood / excellent? Are you changing anything else, like switching from 'b' to 'g' or changing channel number?

Also try NetStumbler. It will give you a more accurrate reading on your signal strength than V Good/Excellent. Compare with and without WPA.

Prisoner6409

Does not appear to be coincidence as the signal strength does indeed return to V.Good or Excellant. I found Netslumber and installed it. When I ran it first it showed 2 devices: "Netgear Adapter Atheros" and "Netgear Adapter NDIS 5.1". It finds nothing on the first but does find my wireless network on the second(NDIS). It reports the following details:

SNR: 34
Signal+: -63
Noise-: -100
SNR+: 37

I am not sure how to decipher this information but I assume the signal strength is 63%. I'm not sure if 63% is good or bad, indeed I'm surprised it is not 100% as the Netgear Adapter is only about 4 feet away from the Netopia Modem. All this is with WEP security. I do have a Bluetooth mouse, not sure if this would have any effect but if it did surely it would effect both WEP and WAP. If the details posted shed any light on this I would appericate any ideas, otherwise I think I will leave well enough alone. It's a 26 digit WEP key so while WAP may be better I don't want to sacrafice signal strength for the extra protection as the wireless network is only used by my son for his PSP so I do not need it active all the time.

Krusty_Clown

Hi Prisoner, can you switch to WPA and tell us what the readings are from NetStumbler?

By the way, they're different drivers for the same device, rather than different devices. Your Wireless card must not support access in the other mode (Atheros), which is why nothing shows up (you card must use a different chipset).

SNR: Signal to noise ration, measured in Decibels.
Signal+ : Is the highest seen signal strength. This is not a percentage. It's measured in dBms (decibel power measure).
Noise-: lowest noise value
SNR+: Highest seen signal to noise value.

Your SNR is fine (in fact, technically it's excellent (26dBm and above).

So, show us the equivalent info for WPA.

Prisoner6409

There are the results I get from Netslumber when I use WAP Protection:

SNR: 47
Signal+: -52
Noise-: -100
SNR+: 48

Most of these numbers would appear fine except the Signal appears lower.

Krusty_Clown

You're getting a better signal than you were earlier, with WEP.
The signal+ will probably fluctuate a bit.. I wouldn't worry about it..

Maybe your router is putting out a less powererful signal when it has to encrypt all of the network traffic. Anyroads you shouldn't notice any service degradation.

Prisoner6409

Sound Krusty, thanks for the explaination. As the router is only feet away from the adapter it makes me wonder what it would be like if I had them a few rooms apart. Anyways I will monitor it over the next few days and run Netslumber now and again, it's a neat little app.

Krusty_Clown

No worries... If you feel up to it, there are knoppix distributions of linux (i.e. bootable from a CD, don't need to be installed) that contain apps like Kismet, which are a lot more powerful than NetStumbler. They'll do things like show wireless networks that don't broadcast their SSIDs, show attempts to probe your network etc.. Example: BackTrack