On 1/4/07, Jack Davis <[EMAIL PROTECTED]> wrote:
I like the Linksys WET-11's, they are a bridge that can be configured with an access point (AP) or a pair of them in a peer to peer mode. They are inexpensive and readily available on the used (e-Bay) market.
If you go with WET-11's get a number of extras. My experience with them in static/lightning conditions (not direct strikes - just active thunderstorm condx) was poor. Popped a number of them internally, some replaced under warranty, others out of warranty. Even un-plugging/plugging one into its own wall-wort power supply blew one of the early models here. They're definitely "consumer grade" made-in-China crap, especially compared with the equipment quality most of us use on our repeater systems. By the time you buy a few spares and spend a summer replacing them (luckily my adventure with them never got that far!), you'll wish you bought something designed to be outdoors in the elements on a tower. Also, if you're feeding power to any device up on the tower via power over Ethernet (PoE) to get it closer to the antenna for reducing feedline losses, I think a few manufacturers make some (venerable) grounding/protection kits. Motorola makes one for sure, for use on their commercial Canopy end-user devices when installed on a residence. I've seen and used only theirs... a gas-discharge tube type thing, nothing fancy, certainly not as good as the Polyphaser brand equipment most of us out here use on our RF lines. But at least it's "something". I think if you're planning on more than a season or two of service out of it, I'd spent a few (a lot?) more bucks and go with something from Tranzeo or Trango Wireless. http://tranzeo.com/ http://www.trangobroadband.com/ Both have various unlicensed frequencies available (900 MHz ISM band, 2.4GHz ISM band, 5.8 GHz... Tranzeo even has the new 4.9 GHz stuff for Homeland Security use, if you somehow have a reason to be there...) Similar to the parts you make your repeater out of, much of this wireless data linking stuff is "you get what you pay for". However, there are still some shoddy systems out there that have prices similar to the good commercial units. I can only personally vouch for these two companies because I've seen their gear in use -- and they've both been around for more than the average "fly by night" manufacturer. Of course used Motorola Canopy gear can also be used point-to-point and I've seen that done too... but setup is less than "intuitive" on that equipment. The wireless ISP that services one of our repeater sites settled on Trango a few years ago -- we've not had any problems with that unit, and it's been in service now for a couple of years on a 9,000' MSL mountain and 80' tower. (Actually the system was reconfigured a while back and we're not the only user on that antenna/system anymore, but that's a very long story... suffice it to say, the gear's still in use, but it's not ours alone anymore.) For the Tranzeo stuff, I got to play around with one owned by another ham who's had it for quite a while now. He doesn't have it permanently mounted on a tower or anything, but the type of service he's put it through was pretty rough, and it survived and worked well for what he was doing with it. Watch out -- both companies (all companies that make this higher-end stuff) have "subscriber" units that are dumb and can only "talk" to an "access point" unit... or they both make medium-smart types of units that are highly configurable that can act as AP's or point to point links, or whatever you desire. The pricing is based on the idea that a small wireless ISP wants CHEAP units at the subscriber's houses, and their head end units are the expensive ones. For most applications hams would probably be using these things, you want the "smart" units or the "medium-smart" units at both ends, so you can configure it as you please -- probably. Buyer beware, and read the specs or talk to the manufacturer about your application, distances involved, etc... before you buy. These low-end commercial systems on un-licensed spectrum seem to be the proper "price point" for linking to a repeater site these days... you can fiddle with cheap stuff, and keep fiddling and fiddling and fiddling... or you can hang a slightly more expensive unit, set it once, put some decent (not great, but decent) lighting protection on it, and walk away for a long time. Small disclaimer: The wall-wort power supplies provided with all of these units are prone to problems. If you can power them off of your nice fat filtered DC supplies, even if you have to jump through some voltage hoops to get there, you'll probably be better off in the long run. We had a power supply go bad on a Trango unit early-on, and it started throwing spurs and crud all over VHF. In our receiver it just sounded like desense that was continuous or overall raising of the noise floor (drastically!) but was EASY to DF, everything kept pointing back to our tower... ruh-roh! Took the duck off an HT and held it to various feedlines on a hunch, and yup... there it was. Radiating up/down the coax since the unit was being fed power via the single Cat 5 Ethernet cable up the tower. Note about that also... technically the Ethernet specifications call for non-shielded Cat 5 cable, but if the run is fairly short, most of these units will put up with using shielded cable just fine... a little cross-talk in the cable may hammer a packet or two, but grounding that shield is a nice thing to do for your RF neighbors on the tower, just in case the Ethernet network itself is throwing some nice RF noises around... There's also no need or capability on most of these units to run 100 Mb/s and most are also half-duplex radios, sometimes full-duplex on the Ethernet side with buffers, sometimes not -- so purchase carefully and plan your data network accordingly... leave lots of head-room via unused bandwidth for turn-around time, etc. But generally they're aim-and-forget. Aiming is the only "hard" part of installing these higher end units. Nate WY0X
