WAP54G - RF pattern & orientation

~ Staring down at my WAP54G sitting on the floor with it's 2 antennas, ~ I was wondering about the pattern...

Think those are regular 2dBi omni "rubber duckies".

~ Is it using diversity - ping pong - so that both are not on at the same ~ time, ~ for either xmit/rcv ? ~ ie - each has it's own donut, and they both are not active at the same exact ~ time ~ therefore there is no addition/subtraction to the pattern.... circle oval -

Yeah, pretty sure that they are doing diversity.

~ SO - if it's upstairs, in a front bedroom, ~ then the donuts are equal and horizontal in plane....

Yep, with the antennas pointing vertically, then the fat part of the donut is horizontal.

I have an old WAP54G and its antennas cover my somewhat sprawling single story house just fine (through plaster-and-lathe interior walls, even.)

~ What if we tilt the antennas, so the donut touches more of downstairs ? ~ And - thinking out loud - what about orientation vs the wall ~ The 2 antenna's along the wall - donuts going left & right along house ~ vs perpendicular to the wall ? ~ ~ hmmm - gonna have to walk around (site survey) tomorrow with Netstumbler ~ and see if the orientation or tilting makes any differences in the actual ~ coverage.

Yep, that's how you do it.

Have fun,

Aaron

It's pretty much a big fat donut. Only one antenna is active at a time, so it's the equivalent of a single 2dBi coaxial antenna, with the added bonus of some pattern distortion produced by the 2nd inactive antenna.

The construction is the same as the WAP11. See:

for some antenna patterns.

Yes. Only one antenna at a time. However, there are some boxes with

2 antennas that always xmit on one of the antennas. I'm not sure if the WAP54G (what hardware version????) is among these.

Sorta. They are fairly independent patterns, but there is some interaction. You'll probably get more interaction from the WAP54G shield, box, table, wall, and nearby metal objects.

Sorta. The pattern is a fairly fat donut. The only nulls are going to be directly above and below the unit. The signal strengths in other directions are more or less equal.

That works if you tilt the "main" antenna instead of the "aux". The diversity system favors one antenna (main) over the other (aux). It only switches if there is a high error rate, such as when there are reflections, nulls, noise, interference, or lack of signal. Even if the signal is marginal, it will continue to use the "main" antenna before grudgingly switching to the "aux". If it weren't for frequency selective fading, you could probably live without the "aux" antenna.

I think (not sure) that looking at the back of the unit, the main antenna is the left antenna.

Your homework for tonight:

I don't understand. The bottom line is that you can't get more signal in one direction, without stealing signal from another. If you want more coverage going up or down, you're going to lose some horizontally. Same with any other pattern modification. Antennas only redirect the RF.

Correct.

Correct.

Correct.

Correct.

More like circle circle if the antenna is a 1/4 L, which most antennas of this type are.

Correct.

That's a good thing if you like better field strength downstairs. Just remember to adjust the antenna(s) downstairs so that their donuts points at eachother, so that they are alined for polarization.

Clients that stands perpendicular to the donut so that the antenna phy element is pointing directly to the client upstairs, that client will suffer from such an orientation. This is a truth with modifications because field pattern indoor when it comes to the dark side of the the pattern is overthrown by reflections. The important thing is to make sure your polarisation is alined. Outdoor (without reflections from walls), if an omni antenna got vertical polarisation (antenna is horizontal) with it's phy tip pointing to a client, and this client got a horizontal polarization with phy element tip pointing up, you got the worst case possible with a theoretically loss of 80dB. If one is pointing horizontal and one is pointing vertical, but both are in the same pane, the theoretically loss is 20dB. This is not something you will measure indoors, and thats why it's very hard to give you any reasonable advice how you should point your antennas other than they all must be polaralized as close as possible to be in the same pane, regardless of reflections, if you want to get the most field strength you can.

I bet you could see a difference of at least 10dB.