# Laptop Wifi Antenna



## springbrk200 (Aug 27, 2004)

I have had a problem connecting to the wireless networks at my school bc I can barely get a signal. I am using an internal wireless card. I have read that I would get better reception if I used a high gain external antenna. 
My question is what adapter cable would I need to connect the antenna (rf cable) to the two little connectors on my internal wireless card? and what kind of range improvement could I expect with a 7.5 dbi antenna?


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## Septerra (Feb 16, 2005)

ummm...if it's internal, I don't believe you can connect external wires, also, try updating your drivers, because if your in Win XP hom or Pro w/ SP2, they will have a built in wireless program to detect wireless access points. Another reason you might get a poor signla is cause too much metal or concrete is in the way from your laptop to the actual access point.


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## springbrk200 (Aug 27, 2004)

all of my drivers are updated, I did that a week ago. The electrical engineer in me says that it has to be possible, just maybe not with the standard wires. I know that the antenna has two wires, with a 50 ohm resistance, and I also know that there are two connection points on the internal wireless card. (I have previously taken it out to look at it. 
Are there any standard wifi wires that would help in this project?


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## springbrk200 (Aug 27, 2004)

Bumb


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## kiwiguy (Aug 17, 2003)

It's not "50 ohms resistance", its "50 ohms impedance", there is a mile of difference.
It's not a resistance in that manner, its a "matched capacitive and inductance" mix that looks like a 50 ohm load to the WiFi card.

Just trying to attache an antenna socket will probably destroy the impedance, which depends on the critical spacing of the wires as much as anything else.

I would suggest that if there is no supplied antenna socket, the act of "adding one" would probably cause the loss of any extra signal that you may gain with a better antenna, it's a science at 2.4 GHz, not an art.

The laptop antenna will be built into the laptop lid in most cases, so they can be quite effective (they are designed to present an impedance of 50 ohms)

Unplugging the WiFi card (assuming its a mini PCI under a panel on the underside of the laptop) and using a PCMCIA one on the side slot may be better, as those are available with an antenna socket.


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## springbrk200 (Aug 27, 2004)

First of all I do fully understand the difference between resistance and inpedance, hence the electrical engineer (undergrad). If you guys think that the only way to add a external antenna socket is to add a pcmcia wireless card what card would you reconmend for the best signal.


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## springbrk200 (Aug 27, 2004)

Does anybody know what type of cable would connect to the two little connectors on the internal wireless card for the internal antenna? If I could find a cable that converted this to a rf cable that would make this whole project possible.


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## TerryNet (Mar 23, 2005)

Post the brand/model of your wireless adapter, and maybe somebody can find some documentation on it.

If you buy a pcmcia wireless card, do you want to look for one with the "best signal" or one that will accept an additional antenna?


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## springbrk200 (Aug 27, 2004)

I would think the pcmcia card that accepts an external antenna would get the best signal if it has a high gain antenna attached to it. 
I talked to the geek squad guys today about it, they said that if I wired it up by hand there is a good chance that I would mess up the impedance,
and somehow if the wire was longer the wireless card would have to output more current and wear it out faster. I don't really think that it will wear out faster, I actually think it will use less current and wear out slower. 

What do you guys think about the possibility of messing up the impedance?

My current wireless card is a broadcom 802.11b/g wlan.


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## springbrk200 (Aug 27, 2004)

Bump


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## JohnWill (Oct 19, 2002)

If you have a card that accepts an external antenna, you should be able to connect a hi-gain model to it. If you don't, you'd be forced to solder to the internal connections.

The Geek Squad doesn't know what they're talking about. While you might have an impedance mis-match, with the power output of a typical WiFi card, you couldn't burn it up if you tried.  The only real way to find out is to get an external antenna, lop the connector off, and solder the leads to the internal antenna feed. Personally, I'd opt for a card with an antenna connector, it's much more likely to work properly.


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## Squashman (Apr 4, 2003)

Are their wires connected to your Internal Wireless card? If not then that is why you are having issues with getting a signal.

I would just buy an external card pcmcia card. I have a Buffalo nic that has the external connector for an extended Antenna. I actually hook up my Cantenna to it.


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## springbrk200 (Aug 27, 2004)

Well I have figured out how to attach an external antenna to my internal wireless card without sodering (I don't think I could sodder nearly small enough to it to work). The connectors on my internal wireless card are ( U.FL also know as MHF ). I then searched ebay and sure enough I can get an adapter to just about any other type. aka ( rp sma). the two connectors that I mentioned are really the connectors to two seperate internal antennas. 

My question now is what kind of antenna would be ideal for mobility and primarily for extended range. I have also found rf signal amplifiers. Would those help, or would they just be a waste of money at over $100.

I have also found several high power internal mini pci wireless cards that claim to have 400mw of power, (I think the standard is 30mW). Would those be worth looking into?


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## JohnWill (Oct 19, 2002)

For an antenna, here's a typical model: [HAI7SIP] Hi-Gain 7dBi Omni-Directional Antenna

For boosting the signal, something like this might help: [HSB2] Hi-Gain WiFi Signal Booster


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## springbrk200 (Aug 27, 2004)

Well I got the u.fl to rp sma pigtail, and a 7dbi high gain antenna with a 6' cable and a magnetic mount that uses a rp sma plug (obviously). We'll see how they do in a couple of days when they arrive. 

I have heard that it is a good idea to have the more powerful antenna on the router than the remote computer. Is this true or is it just easier as the remote computer is mobile.


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## springbrk200 (Aug 27, 2004)

A little interesting side question. What design would work well if I wanted to make something like a cantenna, but use the 9" 7dbi high gain antenna that I already have as part of it? could I just make a hudge cantenna, mybe a 5 gallon bucket?


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## springbrk200 (Aug 27, 2004)

Well I did a little research and found http://www.freeantennas.com/projects/template/ I expect to get a really high gain in the end. 7dbi antennan + 10dbi to 12dbi for the reflector is going to give me about 17dbi to 19dbi for the net gain minus some signal loss for the cable. There is no way I could afford a compercial antenna with this power... AWSOME


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## springbrk200 (Aug 27, 2004)

Well both parts arrived in the mail today. The antenna has given me 12dbi of gain in some instances. I think that is partially due to the antenna placement. I have not attached my reflector yet so this could get interesting.


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## springbrk200 (Aug 27, 2004)

Well I've heard that the bigger the reflector is the more important it becomes to aim it correctly. I haven't had the time to build a big one out of some decent metal.


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## springbrk200 (Aug 27, 2004)

I haven't tried out the big reflector yet, but I try try out the antenna. At time I have gotten a 25db gain with it. not only because it is a high gain antenna, but I have been able to place it better. With out it I couldn't get a single signal, but with it I got 4 solid signals.


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