Wi-Finding Duo: ZyXEL AG-225H And TRENDnet TEW-509UB

Finder Testing

Turning each device on brings it into scanning mode, which lists all of the wireless networks in the area. Holding down the 'Seek' button for two seconds switches the mode between scanning, free network (which displays the networks without any encryption mechanisms), and dedicated (which displays the default network that will be connected to when the device is inserted into a USB slot to act as an adapter) modes.

The similarities of the two devices extend to their signal strengths at different locations, as there was only a 1-2 bar difference between the two during each test, with the ZyXEL barely outperforming the TRENDnet (Table 1).

LocationZyXEL AG-225HTRENDnet TEW-509UB
2 m (6') from AP, same room5 bars5 bars
9 m (30') from AP, same floor, 2 sheetrock walls between4 bars3 bars
12 m (40') from AP, one floor above, wood floor between4 bars2 bars
15 m (50') from AP, 3 interior, 1 exterior walls between3 bars2-3 bars

Table 1: Signal strength test results

I also tested to see if both products could detect APs using beacon periods other than the default of 100mS that most come set to. (This is a weakness that the PCTEL WiFi Seeker has.) I used my trusty Linksys WRT54G for the test and tried beacon period settings of 1, 50, 100 (the default), 200 and 1000 mSec. The TRENDnet had no problem with this test, but the ZyXEL's behavior was a bit odd. I found that the SSID part of the ZyXEL's screen would go blank when it was turned on for the first time in the presence of an access point with a beacon period of something other than 100 mS. The problem could be corrected by pressing the 'Seek' button, but I was able to reproduce the problem multiple times with different beacon period settings.

I then decided to bring both products with me in my everyday activities, to try and get a more real-world feel for how the devices would work. This would allow me to see how vagaries in RF interference, EM radiation, and hawk-eyed network admins with an aversion to people accessing their wireless networks affected the devices.

For the mobile test, I took both devices with me around town in a medium-density urban area, with a sizeable college campus. Whenever I felt like hopping online, I would pull both devices out and check both the number and signal strength of available networks. There were a total of 10 stops involved along the way - ranging from cafes to classrooms to even bus stops. Table 2 shows the number of networks that each device found, along with the average signal strength of all detected networks

Access Points Found4855
Total Bars146171
Average Bars of Signal3.043.11
Table 2: Mobile Test Results

As with the in-building tests, these results paint the devices as being very similar to one another, this time with the TRENDnet slightly edging out the ZyXEL. With this in mind, it is safe to say that the two wireless detectors are essentially equal when it comes to detecting wireless networks. Now let's look at how each device works as a wireless adapter.