SMC2655W Access Point Modifications

External Antenna

I used info at this guy's siteand this guy'sto build this antenna. Pretty simple. I made a couple for about $10. If I do it again, I will use a full-size N connector, instead of the SMA connector the second site suggests, because they are easier to get hold of, and they fit common RF cable.

Pigtail Closeup

The SMC 2655W access point has two external antennas which use the MCX connector, which is a tiny connector. It is relatively easy to remove the external antennas. I got a MCX-to-SMA pigtail from The RF Connectionfor about $20 including shipping.

Power Over Ethernet (POE) Injector

I used info at the Boston Area Wireless UGand NYC Wirelessto make my POE injector. The black cable is the power cord from a 9v transformer. I was lucky because the SMC AP already has the ability to take power off the ethernet cable, so I didn't have to build a demux to get the power back to a power jack at the AP end of the ethernet cable (does that make sense?).

I had the parts to do this sitting around for a couple months, but no time. Then a friend who owed me a favor came by and wanted to do something for me. So I told him to assemble this for me. It would probably have been easier to do it myself, but he had fun. The "Dave's Magic Box" part was his idea.

Power Over Ethernet (POE) Injector Internals

It uses a two-port wall mount box, and two RJ-45 keystone connectors, all from Home Depot for about $10. Instead of wiring in a jack for the 9v transformer, I just cut the leads and stuck them right in the block.

Future Plans

The POE is nice, because I can mount the AP at the end of a long ethernet cable, and not have to worry about running power to it. Next plan is to find/build a waterproof housing for the AP, and mount it and the antenna on a mast outside my house. I'll probably use a 20' length of electrical conduit. I skimmed over a book on antenna design, and it looks like I will have to pay attention to grounding the mast. Check back in a few months (7/17/2002).

Update:I had this running for a couple months, when suddenly it stopped working. Well, not exactly suddenly, because I had just cleaned up the rat's nest of cables under the table. Part of that involved replacing the 50' cable to the SMC AP with a much shorter one, because the AP is still not outside. After some head scratching I figured out that the new, short, CHEAP cable only had two pairs, instead of four, so there were no wires to carry power. I replace it with a real Cat5 cable, and the AP was back working again. The moral is: use good cables. Or is the moral: use good cables when necessary?

As you might guess from the above reference to a short cable, the AP is still not outside. I haven't yet come up with an easy way to put it in a weatherproof enclosure. Still thinking about it, though.

Update:I have found an enclosure for the AP. It's a section of 4" PVC well casing pipe, with two end caps. You can see it assembled here, it looks like a giant vitamin capsule. There is also a shot of it unassembled. I will have to do a little grinding on the AP case to get it to fit inside, and I'll have attach the antenna, and run the ethernet cable inside (so that it's waterproof), and make some kind of mounting bracket. Stay tuned.

Update:I finally finished the enclosure. I cut the PVC pipe to length, and put a slot in it for the cable. I used a hole saw to put a 1" hole in the middle of one end cap, and shoved the antenna through the hole. The pigtail will connect to the AP.

You can see the components here ready for assembly.

Here is the completed system, with the waterproof enclosure containing the AP, a 50' cat5 ethernet cable, and the PoE power injector and power supply. Just cable tie the enclosure somewhere high outside and plug the ethernet cable into your hub, and plug in the power supply, and you have a public (or private) access point. Cost for everything except the AP (PVC, antenna parts, pigtail, PoE, cable) was around $40.

Next step is to do some real-world testing. Darren has a 35 foot crank-up antenna in his yard, so we will put the access point on the top of the antenna, and use a Pocket PC with a wireless card to get an idea of the range. The 2655W has a peak output power of 17.5dBm / 56mW, so I am guessing two or three houses in all directions. It will be interesting to see what kind of signal strength there is inside neighboring houses. Stay tuned!

A writeup on the testing is here.