2.4 GHz commons

My company recently expanded to a building up the block. Two YAGI's & some 802.11g bridges later I'm up and running at a pleasant 60MB/min throughput (actual data).

We did a few test data transfers last week and then had to move one of the antennas to satisfy the new building's landlord. We realigned the antennas but they've not been brought back up yet, as we're waiting for some Cat.5 to be run up into the rafters to accomodate the new antenna position.

Yesterday, a fellow comes into our office asking about the new antennas and some intereference he'd seen on Thursday (the day we did the tests). It turns out he's from company that provides wireless internet access via a 2.4GHz link to one of my neighbors from an antenna almost directly behind one of mine (although about 2 miles away). It turns out my antennas (YAGI's from Buffalo Tech) were interfering with his signals (&apparently vice versa), and one of my sidebands was hitting my neighbor's antenna, decreasing his throughput dramatically.

We had a nice long discussion and he's going to help me help him by replacing one of the antennae with a parabolic and setting up some shielding to take care of the sideband issue w/my neighbor (corporate neighbor, that is).

Since 2.4 GHz is unlicensed and becoming more frequently used, I'm wondering if anyone here has had any similar experiences and was willing to share either anecdotes or technical tips/techniques/resources? Personally, I'm happy to help this guy out as my bandwidth may also increase. Had he approached me in an adversarial fashion, I might not have listened to his ideas, but I certainly could imagine that situation playing out ("Hey, I was here first, shut that damn thing off!") differently.

-Zeke

My house has a few antennas on its roof. We act as a repeater station for some other customers running 802.11b in the valley below the house. I get my internet via another repeater tower a few miles away.

Our ISP reported some intermittent interference that he had trouble tracing. At first he thought it was our 2ghz cordless phone, but we couldn't reproduce the interference problem each time we turned on the phone.

I arrived one day to find larger antennas on the poles on our roof, and I haven't heard him complain about interference since.

He has a lot of experience with this. Are there any specific questions you'd like me to forward to him?

Not yet, but I'll keep your offer in mind if something comes up. The fellow I spoke with looked & talked every bit the radio junkie & seems to know his stuff cold. Frankly, it wasn't something I even considered. Even if I had thought about interference, I'm not sure I'd have done anything differently. I'm just concerned that maybe there's some unwritten ethos/code for this stuff I'm not aware of but should be. I don't want to piss anyone off, but I do want to run my data link!

-Zeke

I have a video/audio/IR sender made by Terk called the Leapfrog that works well, except that someone installed something else in the 2.4 Ghz range that is now interfering with my audio and video. Any ideas how to fix it? I was thinking about throwing breakers to shut off different units in my condo building until the interference went away. Then I'll know who the culprit is. Wouldn't make a lot of friends that way though... :-)

- Jon

Pretty much the only solution I can think of is to use more directional antennae. I've used a similar product, but stopped as I never could get smooth/static free transmission. Oh yeah, alternatively you could put a grounded shield around your devices leaving open the 'line of sight' bewteen the two. That might help some. The shields do have to be grounded or they won't work. Basically aluminum foil hats for your gear.

-Zeke