Decreased Range After Switching To Internal WiFi?

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jamiphar · #1 Post by **jamiphar** » Sun Dec 17, 2006 12:24 am

I just installed a pair of T30 wifi antennas in my T23. I had to do some very light modification to the assemblies, but they seemed to fit pretty well. They seem to work all right with my Broadcom card, but the range seems to be somewhat less than that of my PCMCIA wifi card. The antennas are installed next to the LCD on either side.

Any clue as to why the range is less? I would think if anything that it'd be stronger than before.

#2 Post by **rkawakami** » Sun Dec 17, 2006 12:29 am

I would say that if you aren't using the lids designed for the built-in antennas then you have them up against the metal in the lid and your range will suffer. I tried installing an antenna inside a 600X lid and found that overall, the range was slightly worse than a regular PCMCIA card. That's why I went and put an external antenna jack on one of my 600X systems.

The lids that came with the antennas pre-installed have a "hashed" piece of plastic near the upper corners of the lid. The plastic allows the microwave signals to reach the antennas.

Here's a picture of what I mean (antenna viewport circled; ignore the rest of the picture):

http://www.rkawakami.net/images/t23_lid_antenna.jpg

jamiphar · #3 Post by **jamiphar** » Sun Dec 17, 2006 12:45 am

Oh, so there's kinda a screen there instead of solid plastic as to not obstruct the signal? Right now, the antenna is between the casing and the outer frame. Are the antennas supposed to be in contact with the metal frame?

#4 Post by **rkawakami** » Sun Dec 17, 2006 1:15 am

No, it's not a screen. It is simply a piece of plastic that sits in the cutout area of the metal lid. The antennas are positioned behind them. I would say that your antennas should NOT come into contact with any metal. To do so will change the frequency resonance, which will affect the power and range of the signal. Moreover, placing the antennas behind any metal (i.e., most of the lid) will also reduce your range. The microwave signals of the 802.11a/b/g/n systems can go through plastic fairly easily, but not metal.

There's a post here in the T23 conference that outlines an area next to the battery, under the palmrest, which seems to yield good results. Give me a minute to find it... Okay, here it is:

http://forum.thinkpads.com/viewtopic.php?t=32377

#5 Post by **schen** » Sun Dec 17, 2006 1:18 am

Cr*p James!

I feel so stupid. I had remember you needed that lid, I'd have thrown in my old one in the box I just mailed you! In all the discussion about the other stuff, I completely forgot that, that was what we had started off talking about. It's a little bent in one corner next to the hinge, but it still works!

jamiphar · #6 Post by **jamiphar** » Sun Dec 17, 2006 1:21 am

schen wrote:Cr*p James! I feel so stupid. I had remember you needed that lid, I'd have thrown in my old one in the box I just mailed you! In all the discussion about the other stuff, I completely forgot that, that was what we had started off talking about. It's a little bent in one corner next to the hinge, but it still works!

Oh yes, I forgot all about that too! No biggie, maybe we can work it into the next trade (if I don't have this solved by then)

.

jamiphar · #7 Post by **jamiphar** » Sun Dec 17, 2006 1:24 am

rkawakami wrote:No, it's not a screen. It is simply a piece of plastic that sits in the cutout area of the metal lid. The antennas are positioned behind them. I would say that your antennas should NOT come into contact with any metal. To do so will change the frequency resonance, which will affect the power and range of the signal. Moreover, placing the antennas behind any metal (i.e., most of the lid) will also reduce your range. The microwave signals of the 802.11a/b/g/n systems can go through plastic fairly easily, but not metal.

There's a post here in the T23 conference that outlines an area next to the battery, under the palmrest, which seems to yield good results. Give me a minute to find it... Okay, here it is:

http://forum.thinkpads.com/viewtopic.php?t=32377

I see now. I'd like to keep the antennas in the lid if possible, but I'd move them somewhere else if I could get better range. Maybe I can insulate the antennas with a thin piece of tape or something to keep them from touching the metal in the lid.

#8 Post by **schen** » Sun Dec 17, 2006 1:25 am

Well... I'm sure you've seen my list of parts in the marketplace. Let me know if you are interested in anything.

jamiphar · #9 Post by **jamiphar** » Sun Dec 17, 2006 1:30 am

schen wrote:Well... I'm sure you've seen my list of parts in the marketplace. Let me know if you are interested in anything.

I sure will. I may be interested in your battery sometime soon, I'll let you know if and when I am.

jamiphar · #10 Post by **jamiphar** » Sun Dec 17, 2006 2:14 am

An interesting update here...

On a whim, I decided to open up the T23 again to adjust the antennas. I moved them from being sandwiched between the metal frame and the outer plastic, to just laying flat against the back panel. This time, the antennas are touching nothing but the plastic on the rear panel.
Now the signal has dropped from "Very Good" to "Very Low" because of this. It seems that when the antenna was in contact with the metal, it had a better signal.

#11 Post by **rkawakami** » Sun Dec 17, 2006 2:49 am

If you are talking about the "plastic" LCD lid, I believe that it's actually metal underneath the black paint (titanium, if I'm correct). From what I know about microwave radio signals, any kind of metal is not good. The outer edges of the lid are better because in one direction is the metal lid but the other is the plastic bezel around the LCD panel. That's why your radio signals are getting out better along the edge of the lid.

jamiphar · #12 Post by **jamiphar** » Sun Dec 17, 2006 10:15 am

Hehe, I didn't know it was metal.

Maybe I'll move them somewhere else later on today.

jamiphar · #13 Post by **jamiphar** » Sun Dec 17, 2006 9:15 pm

Back with another update. I put the antennas back where they where originally, but this time with a piece of scotch tape between the metal and the antenna to keep the antenna insulated. This seems to have helped the range quite a bit, I'm connected to a standard 54G router that's two floors up.

I think I'd consider this a success!

chubes · #14 Post by **chubes** » Sun Dec 17, 2006 10:16 pm

Is your range better now with Internal WiFi, versus your old PCMCIA card?

jamiphar · #15 Post by **jamiphar** » Mon Dec 18, 2006 12:09 am

chubes wrote:Is your range better now with Internal WiFi, versus your old PCMCIA card?

Well, I'm not sure. The PCMCIA card shows more bars than the internal one, but the internal one might simply have better signal quality. The internal one will connect and work fine with 1 or 0 bars, but the external one usually would only work with 2 or more.

jamiphar · #16 Post by **jamiphar** » Sat Jan 20, 2007 10:21 pm

One more update. I moved the antennas to the palmrest area, with the end of one right under the IBM ThinkPad logo, and the end of the other under the contour of the center trackpoint button. With the antennas here, my range has increased and is barely any less than the pcmcia card.

Purcy · #17 Post by **Purcy** » Sun Jan 21, 2007 9:59 am

rkawakami wrote:If you are talking about the "plastic" LCD lid, I believe that it's actually metal underneath the black paint (titanium, if I'm correct).

From Thinkpad - Wikipedia:

"Traditionally black, ThinkPads feature innovations such as magnesium or titanium composite cases, TrackPoint pointing device that allows performance near that of a mouse, ThinkLight, an LED keyboard light at the top of the LCD screen"

Right again Ray

alagregg · #18 Post by **alagregg** » Sun Jan 21, 2007 10:34 am

i too have installed a internal wifi on a t23 (without an offical IBM wifi antenna or lid).

i tried three locations for the antenna, i even used an x series antenna on the side of the screen (having dremeled a hole for it).

my best result was attained by putting an antenna where the RFID tag is meant to go (next to the hard disk). I also used a dremel to insure i could get the antenna as close to the outer plastic as possible, and covered the motherboard with masking tape (incase the antenna came into contact with it), before taping the antenna in place.

in addition to this i had to dremel a cable route (for the antenna cable), so everything would lay flat, i made this go out the right of the rfid tag space and over the back of the speaker assembly

This gives me as good a signal as i can get using a pcmcia card.

hope this helps someone
- Al

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