UBNT XR-9 versus XR-5 performance not as good even w/ LOS

I posted this over on Ubiquiti's forum, but I'm confident a lot of you 
subscribed here use UBNT's cards for various things.
So I'm posting this here to see what advice any of you w/ experience 
might have to offer.

I have several UBNT radios including XR2, SR2, XR5, SR5, and XR9
All of my 2 and 5 ghz radios work fantastic w/ 2.6.29.X kernel and 
Madwifi 0.9.4 release. I think it's because they work fine w/ default 20 
mhz channels (up to 54 Mbps) etc.
I use Pac-wireless (LAIRD) OD24-9 and OD24-7 along w/ OD58-12 and their 
Backfire dish ES58-17 and also Superpass panel antennas for AP and 
backhaul setups.
I've also used LAIRD's mesh series OD58-12M and OD24-7M that attach 
nicely to an N-female bulkhead connector right on the enclosure.

My XR-9's are marginal in the Boston area (Cambridge) and somewhat Ok 
out in the country.
I have a couple cheaper hyperlink yagi antennas for testing HG909Y-NM.

I realize XR9 cannot have the channel width set when using regular 
madwifi and it appears ubiquiti's radio driver is no longer developed.
So my question is: What is the proper way to use the XR9 with Madwifi 
0.9.4 or the Madwifi current trunk (which includes the now opensource 
HAL since madwifi-free was merged to the trunk).

My guess is since channels 5 and 6 support 5/10/20 mhz width (these are 
912 Mhz and 917 Mhz center frequencies respectively) then just using 
Madwifi 0.9.4 to set it up on channel 5 or 6 as AP, adhoc, station, etc. 
with proper tx and rx antenna settings to the single MMCX connector 
would get me standard 20mhz channel width? I'm fine with that and 
avoiding channels 4 and 7 since the card can't do 20mhz operation on those.

Here's the conversion chart for the channels:

Channel 4 - 2427 = 907Mhz @ 5/10 Mhz bandwidth
Channel 5 - 2432 = 912Mhz @ 5/10/20Mhz bandwidth
Channel 6 - 2437 = 917Mhz @ 5/10/20Mhz bandwidth
Channel 7 - 2442 = 922Mhz @ 5/10 Mhz bandwidth

Next question: Would going to the madwifi trunk buy my anything in terms 
of functionality? i.e. would I possibly be able to set channel bandwidths?

In my testing if I remember correctly using channel 5 or 6 out in the 
country w/ a couple houses and dense pine trees (no line of sight) 1000 
ft apart I would get -65 signal on each end and about 18 megabit rate. 
In Boston w/ clear line of sight w/ the same setup about 2000 feet apart 
I could only get about -75 on each end w/ only a ping or two. I don't 
remember the reported noise floors.  I'm wondering if only doing the 18 
megabit rate is an indicator that the card is only doing 10 mhz width 
due to default settings madwifi 0.9.4 uses.  With -65 signal and better 
on XR2 or XR5 cards, I can easily do higher rates (36 48 54 Mbps).  I 
don't think there should be too much noise around since we were along 
the Charles river in Cambridge just shooting across the water at 
constant elevation and away from the very dense buildings in Boston 
downtown proper.

I read on UBNT forums also in past posts I think Mike Ford had mentioned 
pac wireless antennas were one of his favorites for XR9 -- they are one 
of my favorites for XR2 and XR5 but I haven't tried anything but the 
cheap hyperlink yagis. I also read someone likes Superpass (which I also 
like their panels for 2.4 ghz stuff) and I could try those.  It's 
unclear if it's an antenna issue, noise, or the card be driven in a way 
it's not meant to be by stock madwifi 0.9.4

But before I try more antennas and go any further with XR9 (or XR7 which 
I have been looking at and wondering about) I wanted to know what I 
could expect and how to properly use the XR9 with Madwifi 0.9.4 latest 
release (which is still binary HAL) or with Madwifi trunk. I'm hoping I 
can just set one of the two 20mhz supporting channels and enjoy using it 
-- but an XR5 w/ similar line of sight with similar gain antennas (and 
not even directional on one but rather omni one end and backfire dish 
the other end) can get signal of -50 or better on both ends w/ easy 48 
or 54 Mbps rates on 2000' line w/ LOS in Cambridge along the charles 
river (same beam path as the XR-9s).

If I cannot expect to reliably use madwifi 0.9.4 or madwifi trunk w/ the 
XR9, then what should I use and where are directions to be able to set 
channel widths w/ some type of known working driver (modified Madwifi or 
UBNT radio driver) that will work on recent 2.6 linux kernels on x86 
hardware. (I use PC engines Alix boards that are designed to tolerate 
the high powered radios of UBNT -- specifically the D series like 3D2 or 
2D3.

Any advice would be appreciated.

Sorry for the long winded message.  I like to include details.

-Eric Malkowski

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