I will be travelling on the road. with a vacation trailer. I would like to carry in my pocket a wifi detector of some kind that can tell me if it detects an 802.11g network, signal strength, channel, mode and presence of encryption. Would appreciate recommendations from others on suitable devices, price range and source.
That, like a lot of the cheap stuff, will only do the first thing the OP wants (not actual computerSSID, channel, mode, encryption, internet availabilty etc)... For something that does all that and fits in your pocket, about the only thing I have found is a PDA (with WiFi, and running something like Ministumbler or Cironds WinC).. Tried the kensington thing, now do the PDA/software thing and have it velcroed to the steering wheel of my car, so I can see the screen as I drive.
That one will only tell you that there's a wi-fi signal, not any of the other information requested. I usually use a laptop running some kind of sniffer software, but that's not pocket size. My XV6700 cell phone runs WiFiFoFum, but that's a rather expensive solution.
One gizmo I've used with an LCD display showing connection details is this one for about $100:
It's also fairly big for pocket size.
97.3 x 28.6 x 14 mm (3.8 x 1.1 x 0.6 inches)
This one has been discontinued, but a new version is coming real-soon-now:
What I've found is that a pocket wi-fi detector is next to useless. If I'm in a coffee shop, I already know that there's wireless. If I'm trying to find an open wi-fi connection in a crowded area, it responds to secured and unsecured networks equally. If I'm in a wi-fi crowded area, the list on the LCD display to far too long. It's both quicker and easier to just fire up the laptop and see what I get, than to try and 2nd guess what's available with a pocket wi-fi detector. The only good thing about them is that they'll detect networks that are not broadcasting their SSID.
Incidentally, there seem to be huge variations in sensitivity among the various wi-fi detector products. I have on of these:
and it's about right, matching the range of my laptop quite well.
There are several USB combination detector/adapter units with LCD displays that fill your bill. Someone already mentioned Trendnet's entry. In addition look at the ZyXEL AG-225H (the one I have) and Linksys' WUSBF54G. These things were all the rage when they first came out a couple of years ago but to get one now you'll probably have to order it online (hope you have time before you leave). Not many brick-and-mortar stores stock them any more. You might be able to get the Linksys at a Circuit City store near you by asking for it to be sent there, and CompUSA at least used to carry both it and the ZyXEL. At any rate, I'd go ahead and pop for one of these rather than settling for one of those cheap LED detectors that only give you a vague idea of what they find-and can't be used as an adapter in a low-signal-strength pinch.