Well among many problems with Atheros cards here is another one!

For 1 year we used a soekris board and MT 2.9.6 as AP Bridge with cm9 (a standard) and Prism 2.5 200mW (b standard) on a client side.
We had to upgrade for a faster cpu and since there is no pcmci slots in new board we purhased 200mw mini pci atheros b/g card.
Now I can't ping some clients with packets more than 256k even if signal is around -60 and client devices are connected in highest rate. And in G standard nothing works. I tried all advised settings for atheros cards and diferent freq.
ack is around 30 and sometimes goes to 380. Links are between 500m and 3km.

When 200mW Atheros card is switched with 100mW Prism 2.5 card signal for the same clients is -70 to -80 but 1024 bytes ping are 10ms with 5% loss max.

I urgently need some ideas.

there is a prism mini-pci its very new chipset but i think its not supported by mikrotik
its called Intersil (Prism Duette ISL3890) didnt try it on windows but i have friend of mine working in big factory in taiwan he said that prism is better in 11b and atheros better 11g so i dont know i would like to share only

following


the atheros card is crazy on windows very very good performance compare to intel cards, so i think just some foucus from mikrotik guys on it it will be better than windows its time only

If it's not config problem, then most probably it's noise. As I written before atheros is very sensitive to noise and prism is not.
It's tested and there is no doubt about it.
Check what's causing the noise and if you can't help it just switch to prism.
Keep in mind that prism can't handle the traffic as athetos can...

there is a noise lvl adjustment in MT+Atheros. Any ideas about number to enter there?