SR71-A

[sldnkarm]

Received a couple of SR71-A cards and LS-SR71 boards last week. I have done some throughput/pps tests in the lab. So far it looks good. I have been running the units in an AP-WDS <-> Station-WDS setup with 20Mhz wide channel in 2.4Ghz (ng).

-40dbm range on either side and holding 140Mbps rate TX/RX. I am seeing 40Mbpsx41Mbps simultaneous upload and download for max throughput. 10k and 11k Packets Per Second with a 64Byte packet for the max pps second test.

So far so good, but can't wait to get them in the field. But I have a couple of questions.

1 - Are these running 3x3 MIMO? Is there control to change that? 2x3

2 - If 3x3 is native, is there a particular ID I should give each MMCX connector? 1 TX 2 RX 3 RX or however it should be?

3 - How is power output of these cards verified? Again which port?

4 - Anything interesting in iwpriv I should know when dealing with these cards?

5 - What type of antenna array should be used? I was thinking three 90degree four foot Til-Teks all vertical. Should I use a horizontal sector for one of them instead of all three vertical? How should they be spaced? 3ft, 6ft between each sector?

6 - Will coax lengths need to be of equal length for each sector?

That's all I have for now...

[WHT]

I'm not sure what you are asking...

"Received a couple of SR71-A cards......What type of antenna array should be used? I was thinking three 90degree four foot Til-Teks all vertical. Should I use a horizontal sector for one of them instead of all three vertical? How should they be spaced? 3ft, 6ft between each sector?"

"A couple of cards" leads me to believe you'll have the LiteStation mounted up in the tower with several SR71 inside with each SR71 connected to its own single one antenna (defeating the MIMO feature) to achieve omni-directional deployment.

"all three vertical" leads me to believe you'll have the LiteStation mounted up in the tower with ONE SR71 inside connected to three different-direction-pointed antennas to achieve omni-directional deployment.

I'm going to assume this is a centrally located AP tower for a WISP deployment.

Going on that assumption, many MIMO projects will fail to meet expectations as there is insufficient MIMO antenna separation. I'll toss out the observation that one foot antenna separation per one hundred range is a good starting point

Therefore a correct implementation would require twelve antennas total.
* Vertical spacing of the three antenna array for one card should be on the order of 100 feet to avail of the MIMO antenna diversity
* Each of three antennas in the three-antenna array should point in the same direction.
* Each array of three antennas should have at least ten feet of horizontal spacing between the arrays.

[sldnkarm]

Sorry I didn't explain in more detail. I have the units in the lab at the moment so I was just looking for information from the group on "best practices" when deploying this gear.

Here goes the example of what I was thinking for PtoMP...

- One LS-SR71 with one SR71-A (running AP-WDS mode)
- Three 90 degree sectors (on for each connection on single SR71-A)
- 45 degree azimuth (this AP will only service 90degrees of the total 360)
- 3 foot horizontal spacing (that's all I can do with the real estate I have available)
-no vertical separation between the three sectors (is this an absolute necessity for proper MIMO operation?

WHT - Have you completed any MIMO field evaluations yet? I am interested if you have...

[WHT]

MIMO is not effective for any WISP operation, so I haven't evaluated it for that purpose.

It isn't effective as the entire principle works on the assumption that in a close-field (under a few hundred feet) RF environment, some signals will take a different path due to reflections. Some paths will be stronger or weaker to the other antenna a mere few inches away. For a WISP that shoots a signal several miles, an inch or two difference (the distance between the MIMO antenna array) in the path length (due to reflection or diffraction) is extremely insignificant. That's why you need your MIMO antennas spaced about a hundred feet apart.

But with MIMO, you cannot point the antennas in different directions at it totally defeats the purpose of "multiple antennas" trying to receive the same signal.