Brian's Brain

I'm disappointed to have to tell y'all that I currently don't have any HSDPA results to share. As promised a few days ago, I dragged the Dell Inspiron D820 down to San Jose with me earlier this week, but it refused to connect to Cingular's network. Every once in a while the connection utility's screen would briefly indicate the network's presence, but then it'd quickly revert back to 'No Connection....Searching For Network'.

In retrospect, I should have realized in advance that my attempt would be unsuccessful. The HSDPA module is backwards-compatible with EDGE and GPRS networks, and I'd seen the same sort of erratic behaviour up here in Sacramento, but I blamed it on suboptimal GSM reception here at the home office. Windows consistently recognizes the HSDPA mini-PCI module's presence, so I'm guessing the laptop's built-in antenna(s) aren't solidly connected to it. I'll work with Dell to see if I can resolve the issue and get you some data next time I'm down in Silicon Valley.

I do, however, have some more EDGE data for you from the Sony Ericsson GC83 card. I headed down to the Embedded Systems Conference early Sunday evening and, suspecting that cell phone usage in the area might be less heavy than when I did my earlier mid-week testing, repeated my Speed Test bandwidth benchmarking. Unfortunately, the outcome wasn't any better, at least in Sacramento. I also re-ran my tests as the train traversed the Sacramento-to-Davis route, and obtained wildly inconsistent results.

I thought the inconsistency might be a reflection of the in-motion connection's bouncing back and forth between cell towers, but it continued even when the train paused for several minutes at Davis station. As proof, I captured three consecutive Speed Test results screens, taken one after the other with no in-between delay and with the train stopped throughout:

• 141 kbps downstream, 90 kbps upstream (the best result I've seen, and indicative that something's better in Davis as compared to Sacramento)
• 62 kbps downstream, 60 kbps upstream, and
• 48 kbps downstream, 87 kbps upstream

I did notice one other interesting thing. The Sony Ericsson Wireless Manager utility indicates what cellular data technology's being employed at any given point in time. I saw it switch from EDGE to GPRS in-between Sacramento and Davis, and back to EDGE once the train neared Davis, indicating that T-Mobile's EDGE coverage isn't yet 100%, even within a few-mile region of territory. This is analogous to how Verizon's Access Manager reports that the connection switches between NationalAccess (1xRTT) and BroadbandAccess (EV-DO) depending on where I am. The GC83, like my Kyocera KPC650, didn't drop the connection during technology transitions, although connection speeds plummeted whenever GPRS was employed (as they do when 1xRTT is employed).

p.s....By the way, I also noticed on Sunday that T-Mobile's EDGE doesn't seem to support the FTP protocol, something that Verizon's EV-DO and Sprint's 1xRTT handle with aplomb. I'm not sure if this is true of all T-Mobile data plans, or is only a reflection of the fact that I'm employing the normally phone-centric $20/month plan.