Project: Convert old antenna into usable wifi antenna.

ThreePts · 04-17-2005

I have an old antenna used with an old SprintBroadband/Speedchoice microwave internet service. The antenna was a 35db yagi antenna that I hope to convert into a useful antenna that can be with my usb adapter. Here is the worklog. Feel free to post here or at the other forum with any comments or concerns. Btw, if anyone can use the yagi antenna part I still have it and would be willing to sell it for a small fee.

http://www.phx2600.com/forum/viewtopic.php?t=188

Thorn · 04-17-2005

Quote:

Originally Posted by ThreePts

I have an old antenna used with an old SprintBroadband/Speedchoice microwave internet service. The antenna was a 35db yagi antenna that I hope to convert into a useful antenna that can be with my usb adapter. Here is the worklog. Feel free to post here or at the other forum with any comments or concerns. Btw, if anyone can use the yagi antenna part I still have it and would be willing to sell it for a small fee.

http://www.phx2600.com/forum/viewtopic.php?t=188

Congrats on (soon) becoming a Daddy.

ThreePts · 04-17-2005

Thanks.

ThreePts · 04-18-2005

Btw, if any of you can think of any uses that I can use with this hack to be able to use the yagi antenna that would be great. I am trying to decide wether or not I have my focal point at the right location. The dish is 8.25inches across and 3.25inches deep. Per the parabolic calculations the focal point would be at about 1.30inches however the shape of this is more of a cone with it being a cylinder which then increases to the dish. Any help would be greatly appreciated.

ThreePts · 04-18-2005

http://threepts.whaddu.com/images/Co...oject/usb1.png
http://threepts.whaddu.com/images/Co...oject/usb2.png

In the second image, in the upper left corner, does that appear to be an antenna connector? Furthermore, can anyone isolate where the actually antenna head would be. Im trying to find the optimal placement for everything. Thanks.

wrzwaldo · 04-18-2005

The point on the second image look like a test point. Is this an adapter you own? FCC ID#?

ThreePts · 04-18-2005

Quote:

Originally Posted by wrzwaldo

Is this an adapter you own? FCC ID#?

Yes this is the one I own. The FCC ID: NHPWLB1403. If you are adding it to your database the model and make are AirLink+ AWLL017/A which is a rebranded Atmel AT76C505

Thorn · 04-18-2005

The antennae are the two curved traces (with the tails) on the far left center of the first picture. There doesn't seem to be any connector.

ThreePts · 04-18-2005

Quote:

Originally Posted by Thorn

The antennae are the two curved traces (with the tails) on the far left center of the first picture.

Thanks for the input. From its appearance would you imagine it would be more directional rather than omni?

wrzwaldo · 04-18-2005

Quote:

Originally Posted by ThreePts

Thanks for the input. From its appearance would you imagine it would be more directional rather than omni?

Omni-Directional?

ThreePts · 04-18-2005

Quote:

Originally Posted by wrzwaldo

Omni-Directional?

correct.

Thorn · 04-18-2005

It's appears to be a 1/8-wave dipole, so it should be mainly omni-directional with a horizonal orientation if the USB body is lying flat. Due to the USB body, the signal is probably somewhat blocked toward the rear.

ThreePts · 04-18-2005

Quote:

Originally Posted by Thorn

Due to the USB body, the signal is probably somewhat blocked toward the rear.

If you are refering to the casing itself, ultimately I would like to remove it if its not necessary. I imagine there are different calculations for the specific type of dish that I have, does anyone know of a calculation that I can use to find the optimal focal point. I am still reluctant to believe that the parabolic calculations will work correctly with this. Any input would be great.

Thorn · 04-19-2005

Quote:

Originally Posted by ThreePts

If you are refering to the casing itself, ultimately I would like to remove it if its not necessary. I imagine there are different calculations for the specific type of dish that I have, does anyone know of a calculation that I can use to find the optimal focal point. I am still reluctant to believe that the parabolic calculations will work correctly with this. Any input would be great.

Not so much the case as the PCB, the RF section's RF shield and the USB connector. All of the will block the signals somewhat. In a normal use (where the USB is inserted directly into a PC/Laptop it really wouldn't matter as that's the last place you'd care about getting any signal. In this use, all I'm saying is that you probably can't expect a perfect omni-directional pattern.

Scruge · 04-20-2005

Quote:

Originally Posted by ThreePts

If you are refering to the casing itself, ultimately I would like to remove it if its not necessary. I imagine there are different calculations for the specific type of dish that I have, does anyone know of a calculation that I can use to find the optimal focal point. I am still reluctant to believe that the parabolic calculations will work correctly with this. Any input would be great.

You might try experimenting with the orientation of the usb card with respect to the reflector. I've found from working with usb wifi card with LTCC antenna and a parabolic reflector that the gain tends to change no more than a few db.
I attached a picture of a low cost and simple setup I did in a few hours.
Some of the advantages are that the configuration can be easily tuned by sliding the USB card in the pvc pipe until you find the optimum gain (focal point). Plus its easy to weather proof for outdoor use. You can also experiment with feeding your usb card into the pvc pipe from the front. This might yeild positive results if you have a perfect parabolic. In my case because my bowl had a flat bottom most of the gain was coming from the sides. Although the 8.5" bowl should have produced roughly 11dbi gain, it wasn't 100% parabolic. The bowl lost it's parabolic properties at a diameter of 4".
I estimated the gain by calculating the gain of a 8.5" dish and then subtracting the gain of a 4" dish (the area of the bowl that wasn't parabolic). The results came pretty close to my actual measurements of 6.3dbi

04-17-2005	#1 (permalink)
ThreePts Desert Stumbler Join Date: Jul 2003 Location: Phoenix, AZ Posts: 136	Project: Convert old antenna into usable wifi antenna. I have an old antenna used with an old SprintBroadband/Speedchoice microwave internet service. The antenna was a 35db yagi antenna that I hope to convert into a useful antenna that can be with my usb adapter. Here is the worklog. Feel free to post here or at the other forum with any comments or concerns. Btw, if anyone can use the yagi antenna part I still have it and would be willing to sell it for a small fee. http://www.phx2600.com/forum/viewtopic.php?t=188 __________________ WebGoonies.com: Life of a father to be... )( WarWounds )(

04-17-2005	#3 (permalink)
ThreePts Desert Stumbler Join Date: Jul 2003 Location: Phoenix, AZ Posts: 136	Thanks. __________________ WebGoonies.com: Life of a father to be... )( WarWounds )(

04-18-2005	#4 (permalink)
ThreePts Desert Stumbler Join Date: Jul 2003 Location: Phoenix, AZ Posts: 136	Btw, if any of you can think of any uses that I can use with this hack to be able to use the yagi antenna that would be great. I am trying to decide wether or not I have my focal point at the right location. The dish is 8.25inches across and 3.25inches deep. Per the parabolic calculations the focal point would be at about 1.30inches however the shape of this is more of a cone with it being a cylinder which then increases to the dish. Any help would be greatly appreciated. __________________ WebGoonies.com: Life of a father to be... )( WarWounds )(

04-18-2005	#5 (permalink)
ThreePts Desert Stumbler Join Date: Jul 2003 Location: Phoenix, AZ Posts: 136	http://threepts.whaddu.com/images/Co...oject/usb1.png http://threepts.whaddu.com/images/Co...oject/usb2.png In the second image, in the upper left corner, does that appear to be an antenna connector? Furthermore, can anyone isolate where the actually antenna head would be. Im trying to find the optimal placement for everything. Thanks. __________________ WebGoonies.com: Life of a father to be... )( WarWounds )( Last edited by Dutch : 04-18-2005 at 10:24 AM. Reason: Changed [IMG] to [URL] tags

04-18-2005	#6 (permalink)
wrzwaldo I amuse you? Join Date: Dec 2003 Posts: 9,147	The point on the second image look like a test point. Is this an adapter you own? FCC ID#? Last edited by wrzwaldo : 04-18-2005 at 10:42 AM.

04-18-2005	#8 (permalink)
Thorn Did you do the math? Join Date: Apr 2002 Location: Villa Straylight Posts: 10,361	The antennae are the two curved traces (with the tails) on the far left center of the first picture. There doesn't seem to be any connector. __________________ Thorn "Read Altas Shrugged. Compare it to today. Repeat as necessary"

04-18-2005	#12 (permalink)
Thorn Did you do the math? Join Date: Apr 2002 Location: Villa Straylight Posts: 10,361	It's appears to be a 1/8-wave dipole, so it should be mainly omni-directional with a horizonal orientation if the USB body is lying flat. Due to the USB body, the signal is probably somewhat blocked toward the rear. __________________ Thorn "Read Altas Shrugged. Compare it to today. Repeat as necessary"

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