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I purchased a USB wireless adaptor: EDIMAX EW-7811Un Wireless Nano Adapter . For the first time use,

  • it only detects the router in the same apartment. My internal wireless adaptor (in Lenovo T400) when it works can detect not only the router in the same apartment but also other routers in neighbour apartments. But my previous impression from reading on the internet is that a USB adaptor can detect routers that is farther away than an internal adapter can. So am I wrong?

  • also the speed seems slower with the USB one than with the internal one. Is it normal?


share|improve this question
Is there anything else connected via USB? You could be running into bus speed issues, along with the antenna/signal and single/dual-band issues. – ernie Jul 18 '13 at 20:30
mouse is connected via USB. Will that matter much? – Tim Jul 18 '13 at 20:33
Unlikely . . . I was more wondering maybe if you had external drives or the like. I'd also assumed you had connected to a USB2.0 port. The lack of a real antenna and the single-band will most likely be your biggest issues. – ernie Jul 18 '13 at 20:35
up vote 3 down vote accepted

How an adapter connects to the computer has no effect whatsoever on its range.

Your laptop has a built in Intel 5300 WiFi chipset capable of multiple simultaneous streams through your laptop's two high-quality built in antennas. How can a cheap, low-end adapter with a single antenna smaller than my thumbnail possibly compete?

Also, your internal WiFi adapter is dual-band (2.4GHz and 5GHz). The USB adapter you bought is 2.4GHz only.

share|improve this answer
Thanks! (1) I was wondering why only one router is detected? (2) Do USB or internal make difference on speed? – Tim Jul 18 '13 at 19:57
(1) Probably because the tiny antenna on your external adapter is no match for the multiple antennas built into your laptop. (2) Not likely, but it's hard to know without knowing what you mean by "speed". More likely, a poor antenna is resulting in a poor link. – David Schwartz Jul 18 '13 at 20:01
What kinds of USB adaptors will you recommend, which is comparable to my internal one? – Tim Jul 18 '13 at 20:05
Something like the USB-N53 or the RNX-N600UBE. Also, your internal WiFi adapter is dual-band (2.4GHz/5GHz). Your USB adapter is single band. – David Schwartz Jul 18 '13 at 20:09
Thanks, David! Can the two USB wireless adaptors work with my laptop without its own power chord? – Tim Jul 20 '13 at 22:40

It is entirely based on the internal components of the individual adapters. Perhaps your internal adapter is wired to use the case as an antenna or your USB one is more cheaply made. Also, it could be a power issue, whereas your USB port is underpowered and doesn't receive as good of a signal because of it.

As for speed, you already acknowledged that the internal receives more signals, therefor it is receiving a better signal as well or the USB is simply older technology (you'll need to be more specific on your adapter information)

You could try a powered USB hub to see if that helps. If not, perhaps you should buy a better wireless adapter. You can find ones with external antennas and that should help with your issues.

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Thanks! Forgot to mention the internal adaptor is a wireless one. – Tim Jul 18 '13 at 20:06

This entirely depends on the technology in the USB adapter that you purchased. There are many different types of WiFi technologies. Simply having a "USB" adapter doesn't mean that it is any better than your internal card. As David Schwartz said, how the card connects to your computer doesn't make much of a difference.

For instance, there are major differences between radio technologies in Wireless-B, Wireless-G, and Wireless-N. Those radio technologies have significantly different ranges and maximum download/upload speeds. If your internet card is a Wireless-N card, and you purchased a Wireless B/G card, then you purchased a card that is essentially worse in terms of range and speed.

I can't resist comparing this to cars. Just because you drive a "Ford" doesn't mean you have more horsepower than your "Chevy". It all depends on the model and what's under the hood.

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Thanks! Can you make some specific comments on my USB and internal adaptors? My laptop is Lenovo T400 with its own default internal adaptor, and my USB adaptor is "SUS PCE-N13 Wireless Adapter IEEE 802.11b/g/n PCI Express 150/300Mbps Transfer/Receive Rate 64-bit/128-bit WEP, TKIP, and AES WI-Fi alliance WPA, WPA2" – Tim Jul 18 '13 at 20:03
The difference to me that sticks out is that the antenna that is built in to T-series Lenovo notebooks is much bigger than the one in the USB adapter you bought. That would be the culprit in range differences. In terms of speed in a good connection though, the USB card should perform better. Again, the antenna would be the reason you don't get as good of a range. I am actually using a T430 with the same card in it to type this right now. – Moses Jul 18 '13 at 20:07
Do you have recommendations on USB adaptor comparable to my internal one? – Tim Jul 18 '13 at 20:09
Stack Exchange isn't meant for product recommendations, but why are you looking for a replacement adapter in the first place? – Michael Kjörling Jul 18 '13 at 20:23
my current USB one only finds one router. my internal one is not working whenver I move my laptop. – Tim Jul 18 '13 at 20:34

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