I think I read here about there being a laptop PC available with its wireless antenna mounted in the top of the lid so that when opened and in use the antenna is much more out in the open than is the PC Card version I have (it hardly works at all unless I put the laptop on a piece of foam to get its antenna off the table surface).
I searched various phrases on this newsgroup and got nothing. Also I've done some general searches and haven't found anything definite.
As a last resort before posting this I asked a couple of salesmen at the PC stores. They both gave me a blank look and it was clear none of them had ever thought about where the wireless antenna is placed in any laptops they sell.
The antenna of my R51 Thinkpad is in the lid, and for no particular reason, I'd always just assumed that laptops with "built in" WiFi always had the antenna there.
Almost every laptop with "built-in" wireless has its antenna in the lid, but I've found that signal strength with these is usually a bit
*worse* compared to the antennas attached to a PC card. One problem might be that they're so close to the LCD display and its aluminum shielding. The very thin coaxial cable linking these lid antennas to the radio card down below (not an issue with PC cards) can also lose a few dB of signal.
Is the table you have to use the foam spacer on made of metal?
One thing you might try is repointing the antennas on your AP/router so that they're closer to being horizontal, to better match polarization with the PC cards. Try to tilt them to be roughly parallel / broadside with the protruding part of your PC card antenna.
Also, it can be helpful to place the AP/router as high as possible, and as far away from other objects as you can (especially anything metal).
I've found the lid antenna on my Compaq 2200 to be surprisingly good compared to my PCI card based antenna. PCI antennas are usually hopelessly positioned to pick up anything.
My Thinkpad R51 has great reception. Better than any other wireless adapter with built-in antenna that I have, including a USB adapter mounted at the same height. I believe that it has two antennas, one in the side and one at the top.
Other laptops may not be as good. Try to find reviews of laptops that cover the built-in wireless.
Also, it must surely have something to do with the internal wireless adapter's power and sensitivity. Some are better than others, I imagine.
Good advice. Pcmcia cards have horizontal polarization. Of cource if you switch your AP antenna(s) to horizontal, then you may want to adjust the other antennas in your network to horizontal as well.
Most current laptops have two antennas in the LCD section. One is usually near the top of the screen and mounted horizontally. The other is usually on the right side and mounted vertically. However, there are exceptions and abominations. For example, this loser has the antennas mounted on the hinges:
Compaq 2120US.
There are also conglomerations, where both antennas are combined into a single structure, thereby negating any benifits to diversity reception. I'm too lazy to find a photo.
No, the LCD panel antennas are often NOT all that great. The LCD panel leaves very little space for two full size (1/2 wave long dipole or about 6cm long) antennas. The proximity to the metal in the LCD panel back, the long thin RG316 high loss coax cable, and sometimes the reduction in size using ceramic substrates and PIFA configuation, can result in inferior antenna gain and a weird antenna pattern. Search eBay for "Mini PCI antenna" for examples.
I could think of better reasons to buy a specific laptop than the location of the antenna. Have you considered an external antenna? See:
for some ideas and butchery.
Duh. If they knew the answer, they would be designing the laptops, not selling them.
Nope. Not for every possible laptop that was ever manufactured or sold. Methinks you might be asking too much.
Try these sites:
They have disassembly instructions which usually show photos of the guts. You should get a clue as to the location of the antennas. For example, here's the insides of a Toshiblah Satellite 1415 and M55 showing the two PIFA antennas at the top of the display section:
You can also sometimes get photos of the laptop insides on the FCC ID web pile. The problem is that you'll need to know the FCC ID of the laptop as the search engine is somewhat broken:
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