Hello, our company just got r52n-s, we were going to use them just as replacements for R52Hs, but actual default rates for b/g modes were much lower then specified in cards datasheet.
I found out here that this is normal when the card is working in n mode with 2 antennas, but this is not the case, and I couldn’t find any answer in internet, so can anybody tell me if it is safe to increase tx powers up to values found in datasheet? any information will be greatly appreciated, thanks 
Okay, so after lot of digging and testing I think I’ve finally found answer on my questions, my testing board was rb433 with ROS 4.4 installed an R52n card. So, speaking of new R52n wifi card, main difference from older a/b/g cards is that it uses two Rx/Tx chains, you can think of them like two wifi cards on single pcb; one chain, HT0 (wifi card) is connected to J2 ufl connector and another chain, HT1 is connected to J3 connector. So, the maximal TX power of 23db (card’s datasheet says 25db, but in 2,4GHz g-only mode winbox reports maximum total tx power of only 23dbm 
) is reached only when both chains are working, which implies that you need 2 antennas connected to your card to have that 200mW tx power, and in case if you use only one chain for data transmitting, that power is halved, and you get only 100mW (20dbm) tx power. and i’m not talking only about n mode, this is true for older a/b/g modes also!
This is very disappointing because mikrotik advertises its n family cards as replacements for older r52H cards, and as it seems from above, these cards are far from older models in means of TX power, especially when it comes to point-to-point single antenna installations (14dbm@54Mbps in 802.11a single chain setup).
Hi Intellgio,
I am trying to run two single antenna boards with the R52n cards. They are in a test scenario only 2 meters apart.
If both chains (“0” + “1”) are enabled I get highest speeds of tcp 42Mb. But only one antenna (j3) is connected. Obviously in such close prox. environment the other connector (j2) still picks up enough signal to cooperat.
When I close one chain on both antenna’s speed fall back to a merely 20Mb! Very dissapointing! Normal ´g´ or ´a´ performance is better!
Can we both conclude single antenna setup with the ´n´ cards is not feasable for MT?
How are these gusy of Ubiquity do this with single antenna units? They claim up to 100Mb!
I find anyway very little info on MT forum and wiki about setting up ´n´ cards in both dual and single antenna setup environments. You would expect MT would supply us with lots more info on these cards and how to use them to make them a succes…
It would be very nice if some vendor develops a small dual antenna system for the MT boards or I see myself placing my next order with ubiquity. To stay ahead of the Wimax guys I need higher speeds under difficult LOS and interferance situations… I was hoping ´n´ would bring me this.
Hey Rudy
So you must be testing n mode on new cards, first thing that might be wrong in your setup is running a chain on transmitting without antenna plugged, such setup can fry your wifi card easily, and the second is that you should keep your signals below -40db because too strong signal also affects the performance of card, and 2 meter distance between your 2 stations is much less than is needed to achieve signal much more than -40db. Try to use just single chain with either card tx powers reduced or some dielectric stuff between them, to reduce the signal.
I think in your case it’s still bit early to say that these cards wont do, there are a lot of success stories posted on this forums, just try to fix the issues mentioned above and post your results.
And about ubiquity, the have single antenna bullet n-s, 25dbm tx power, no cable loss, we tested them and they give 60MB tcp traffic in 5km point-to-point setup, and price is also really reasonable, we’re going to stick to them until mikrotik offers some competitive stuff.I really love that universal RouterOS, which is really like clay, you can make virtually anything from it, Mikrotik, we’re waiting for you
Hi Intellgio,
I tried every possible combination on the chains. But only when both are enabled high speeds are possible.
Power down: I tried to power down as much as possible but below 2 or 3dBi the link became very unstable.
I have one link running in my network on a dual antenna setup with ´n´ and can achieve easy 50-60Mbps tcp (bandwith test) over it so if both chains can be used it works fine.
I was only hoping P2MP with signle antenna’s would see an increase too.
Re all the success stories, I don’t see so many with real live traffic. The only successes I see is with dual antenna setups on mediate to long distances. But only from a few guys.
Most of the ´success´ stories is with udp traffic throughput test and one direction only.
And since I hardly read anything (or see suppliers) solutions for PtMP situation with ´n´ mode setup`s on single antenna’s with routeboards I take it MT equipment is just not developed enough to arrange something like it. They probably need a good manufacturer to make them a small dual pol. antenna for their small boards that can be produced small and cheap.
I think Ubiquity has a good advance in developments here. The problem is I don’t want to migrate my network into Ubiquity and the failure rate of their antenna’s is almost twice as high as equipments build around MT stuff.
So we´ll see what’s happening…