one minute regular speed drop on minitar ap, each minute transfer rate drops off Options

[cairnfree]

I have a funny little issue... no doubt simple.

Every minute I get a performance drop. Using two minitar 802.11 b AP's with latest firmware, one in ap mode, the other in Stat-Inf mode. A monowall router is attached at each end.

The speed hammers along at about 550 kB sec, then drops to zero for a second or three. It then ramps up to 550 kB a second again.

I don't think it is a client / router / os fault / os configuration issue - all those components / possible causes have been replaced, eliminated or swapped out.

The only components left are the AP's themselves, their power supplies, and the antennas. Of course, they happen to be stuck 2.5 meters up on poles transmitting over city rooftops with whatever interference may be up there... There are actually a few AP's in the area with close channel numbers and a few other wireless networks of my own, and a bunch of wireless phones, microwaves, etc etc etc.

The problem also shows as ping -t at a solid 2 ms, until each minute a timeout or 50-500 ms delay. Fixing it isn't critical - my Asterisk VOIP box handles it fine and a pptp vpn stays connected all day no worries.

The AP's are used over a 3-4 km link. I use new (probably overkill) antennas - large wave guide at the AP end, and a large uni hills at the Stat-Inf end, using POE over 10-15 meter worth of cat5 and professionally made pigleads . I beam through a couple of large mango trees in the middle of the signal path.

I can email / post a dumeter picture. It mostly shows a pretty distinctive saw-edge tranfer pattern. Sometimes (depending on which computers I use / routers / proxies / protocol etc) the transfer is almost solid, but there is still a clear drop every minute or thereabouts.

Any ideas? Any software or scripts I can run to try to graph signal strengths like netstumbler does to gather more clues?

Cheers

[serialmonkey]

Hi there,

For your kind of setup you are probably better to use bridge-point-to-point mode I would think. Do you get the dropouts in this configuration ?

S.

[cairnfree]

Thanks for the suggestion but I don't think bridge mode is for me. I'll leave it as is - after all it is working well enough to be fully functional. I thought it might be an obvious one.

Thanks

[serialmonkey]

If you have more than a single PC at either end then you want bridged mode. Client-infrastructure mode isn't built for having more than a single PC wired behind the AP and can cause lots of different funny problems (though if you are running a router at each end then you may actually get around 99.9% of the problems anyway as they are mostly related to DHCP and other broadcast/multicast traffic).

S.