I wanted to update this thread. I had ordered some cheap 14dBi patch antennas and they arrived today. I setup two Metal 52 ACs on stands at about 200 feet from each with the stock 6dBi antennashttp://forum.mikrotik.com/viewtopic.php?f=2&t=109647
and noted -52/-50 transmit (high and low numbers) and -51/-49 receive gain from the web interface on one of the radios. So lets call it -51 average gain.
Switched one antenna to the panel 14 dBi and got -39/42 and -35/38 so lets call it -40.5
Switched the other antenna and got a nice -26/-27 and -23/-24 so lets call this -26.5
The gain improvements are way better than I would expect. I would expect (14-6)*2 or 16 dBm gain from the two antennas. Instead I got 51-26.5 or 24.5 dBm gain.
I picked up an additional 8.5 dBm or so. This makes me wonder if the stock antennas are really 6dBi or really more like 2dBi antennas???
Has there been any reported problems with the stock antennas?
I'll do some additional testing in the field this weekend.