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View Full Version : Has anyone used this parabolic reflector template to boost their wireless signal?



kevdog
December 6th, 2007, 05:10 AM
Just wondering if anyone had used this wireless parabolic reflector template to boost their wireless signal. It seems like it would work, but Im just looking for some feed back:

http://www.freeantennas.com/projects/template2/index.html

steveneddy
December 6th, 2007, 05:18 AM
LOL - I expected this to be a Rav Tux thread.

:popcorn:

ryanVickers
December 6th, 2007, 05:20 AM
this is so going on the "you know your a geek" forum lol

kevdog
December 6th, 2007, 05:24 AM
this is so going on the "you know your a geek" forum lol


Ok -- maybe you're right about this -- however I think everyone here in the forums the responds regularly probably has some geek in them.

mellowd
December 6th, 2007, 05:26 AM
A friend of mine did make a "cantenna" once and it actually worked very well.

K.Mandla
December 6th, 2007, 05:28 AM
CoachDANNY works with them sometimes, and shows how to make them too, if I remember right.

http://coachdanny.blogspot.com/2007/10/how-good-is-windsurfer.html

n3tfury
December 6th, 2007, 11:27 AM
Just wondering if anyone had used this wireless parabolic reflector template to boost their wireless signal. It seems like it would work, but Im just looking for some feed back:

http://www.freeantennas.com/projects/template2/index.html

it's practically free, why not try it? i've used various home-made antennas including my own built cantenna and have had good success with all of them. ymmv.

regomodo
December 6th, 2007, 01:54 PM
yep, it works. I used the paper template backed with foil

kevdog
December 6th, 2007, 02:10 PM
How much does it boost your wireless signal?

n3tfury
December 6th, 2007, 02:57 PM
How much does it boost your wireless signal?

an increase is an increase right? how would you know how to use the number he gives you anyway? 2db, 6db or more - do you know how much this increases your range?

kevdog
December 7th, 2007, 12:59 AM
Thats basically my question -- what does a 2-9 db increase translate to?

ryanVickers
December 7th, 2007, 01:09 AM
why exactly is the signal being measured in volume units? lol

kevdog
December 7th, 2007, 01:13 AM
If I can remember from my engineering days -- a -3 db loss in signal means the signal has lost 50% of its strength?? Just want to confirm.

satx
December 7th, 2007, 03:15 AM
-3dB equates to 50% loss. All these discussions are interesting but when we speak of gain we are referencing to a simple dipole antenna (Gain equals 0 dB).

Parabolic reflectors have the highest gain: 10 to 30dB, Yagi (boom with multiple elements) 2-20 dB or so. At 900 MHz, Yagi boom length about 13". At wireless frequencies, 2.4 GHz, boom is about 4".

No doubt a parabolic reflector can increase gain- but then again, how much gain do you really want? Unless you are talking about your wireless card and you are wardriving! For me, just need wireless range to be contained within walls of my house, thank you.

SATX

kevdog
December 7th, 2007, 03:29 AM
Ok -- so with a 50% gain -- assuming a elementary 3 db gain, under perfect conditions (no walls, interference, etc -- just wide open space) how much more range should I expect.

satx
December 7th, 2007, 03:48 AM
Well, that's a bit difficult to estimate. Now we are talking Effective Radiated Power, ERP. Rule of thumb says you get about a mile for every watt of radiated power (ideal conditions). The power from the WAP to the antenna has not changed.

Best way to test would be to take laptop and compare range between normal WAP antenna and Parabolic Reflector antenna. Not knowing what gain, power you have right now makes it difficult to estimate degree of improvement.

So, bottom line, don't know what your range will be! Sorry to be vague, but don't have enough data.

BTW, remember that a parabolic reflector is highly directional- just like your satellite dish antenna- pretty much line of sight (dish has to be aligned with satellite, etc.). I would only use this kind of antenna as a receiver rather than a transmitter.

SATX

kevdog
December 7th, 2007, 04:04 AM
200mW transmit power. Since Im not looking for a percentage increase, rather an absolute power do you really need to know a gain??

1 mile = 1 watt power
1 mile = 1000 watts power
.20 mile = 200mW power (Im thinking that rule of thumb is a little off -- no way am I even getting close to this -- Im guessing a most Im getting roughly 400 linear feet.

1 mile = 5280 feat
.20 mile = 1056 feat (400/1056=0.378)

So I just going to say for me Im roughly getting 35% of the theoretical value as far as range.

satx
December 7th, 2007, 04:13 AM
Maybe not. Just read the link you provided. The windsurfer says 9 dBi gain- dBi is in units of 3dB, so I am estimating about 150% improvement over a non-parabolic reflector. Gain/power/range are not necessarily linear. But if you got 100 foot range, this may boost to another 50 or so feet. Just guesstimating here!

So you are getting a 400 foot range? What do you get without the reflector?

kevdog
December 7th, 2007, 04:18 AM
Hmm, an experiment -- looks like I will have to delve into this topic this weekend.

satx
December 7th, 2007, 04:37 AM
Hey, let me know what you find out. The antenna itself looks pretty neat, and simple to make.

SATX

adam.tropics
December 7th, 2007, 04:39 AM
Hmm, an experiment -- looks like I will have to delve into this topic this weekend.

Remember to post back, really interesting.

tgalati4
December 7th, 2007, 05:24 PM
I've been using one for a couple of years. Using a Mac Powerbook, my signal strength went from ~30% to ~52% in the far corner of my backyard (where I smoke). It's roughly 150 feet and going through 3 or 4 rooms. Front yard signal is similarly reduced.

Because you can swivel the antenna (with it's roughly 140 deg coverage) you can beam the signal where you need it.

I can watch High Def movie trailers in the backyard through wireless streaming, so I would say it's a pretty robust, and geeky, solution.

Lostincyberspace
December 7th, 2007, 06:45 PM
I use one not exactly the same but the signal when directed now will go 2-300 feet.

adam.tropics
December 8th, 2007, 07:59 AM
Just tried a really simple version, no pattern, just card covered in foil, rolled, and sat behind the antenna. I am slightly surprised. Distance wasn't really an issue for me, as my property is fairly small, but signal strength has always bothered me. Now I have a reported 15% gain. Will try the proper pattern when I get chance and see if that helps any further.

D-EJ915
December 8th, 2007, 08:26 AM
Also having a good antenna on the computer helps a lot too, I get like 3-4x times the signal and range as my dad's old Compaq does with my Sony T250.

adam.tropics
December 8th, 2007, 08:34 AM
Not sure you can do much with a laptop in that regard though....although if I remember there did used to be a mod for macbooks, guess that might translate.

jpkotta
December 8th, 2007, 09:21 AM
Wouldn't your range increase go like the sqrt of the gain increase? So for 3dB gain, you get 1.41 times the range, and in general the range increase would be 10^[gain/20]. Note that the inherent trade off for gain is directionality - you need to aim your antenna.

http://en.wikipedia.org/wiki/Friis_transmission_equation

n3tfury
December 8th, 2007, 01:19 PM
Not sure you can do much with a laptop in that regard though....although if I remember there did used to be a mod for macbooks, guess that might translate.

you can get an external card with an antenna. i was just going to recommend a buffalo card, but saw that they're having major legality issues and you can't view any of the wireless devices on their website.

http://www.buffalotech.com/press/releases/buffalo-issues-a-statement-about-the-csiro-appeal/

anyway, something like an Orinoco Gold card would suffice also.

adam.tropics
December 8th, 2007, 01:25 PM
you can get an external card with an antenna. i was just going to recommend a buffalo card, but saw that they're having major legality issues and you can't view any of the wireless devices on their website.

http://www.buffalotech.com/press/releases/buffalo-issues-a-statement-about-the-csiro-appeal/

anyway, something like an Orinoco Gold card would suffice also.

Not wanting to steal the thread, but had a look at the Orinoco, and without giving away my total lack of understanding about such things: would it be possible to use both that, and an existing internal wireless, kind of daisy chained to increase speed on the internal network to my laptop?

n3tfury
December 8th, 2007, 01:28 PM
i don't think that's possible because i've tried it on the two laptops that i have and you have to disable one to get the other to work.

nand
December 8th, 2007, 03:21 PM
Here is mine (5dbm antenna plus the parabola on a rt73 one)!

http://bp2.blogger.com/_JiUNrQYYUUw/RwCABzTR_DI/AAAAAAAAAHU/NcnOwp-Rq_k/s400/IMG_0633.JPG

Result? I gained 10 to 15 db. And when usually I get -75dbm, which is quite low, -60dbm greatly increase the stability of the connection!!

bailout
December 8th, 2007, 04:07 PM
Will this idea make any difference on the receiver arial (a usb adapter)?

Envirotech
December 8th, 2007, 04:44 PM
Not knowing all the technical stuff behind it. I have used it with great success. Using a standard linksys wireless G router and internal linksys desktop card (G). We were trying to get the wireless signal to my mothers house which is 200-250 ft away from us. She was getting no signal. After using this she was showing 100% on here xp box and it showed she was getting the full 54Mbits and has been fully stable for the last year. The only technical thing I know about it is it changes the signal from omni directional to directional.

n3tfury
December 8th, 2007, 04:50 PM
Not knowing all the technical stuff behind it. I have used it with great success. Using a standard linksys wireless G router and internal linksys desktop card (G). We were trying to get the wireless signal to my mothers house which is 200-250 ft away from us. She was getting no signal. After using this she was showing 100% on here xp box and it showed she was getting the full 54Mbits and has been fully stable for the last year. The only technical thing I know about it is it changes the signal from omni directional to directional.

you used the design in the first post?

esaym
December 8th, 2007, 05:56 PM
http://martybugs.net/wireless/

satx
December 9th, 2007, 08:10 PM
jpkotta:

Ideally yes. But if you read further down in your post link you get the additional complicating factors so that a simple calculation will probably be very optimistic. But, good catch- and can serve as a "best case" result.

SATX

kevdog
December 10th, 2007, 05:14 AM
Just a quick question

I understand that with the parabolic reflector you are changing from a omni-directional antenae to a directional one -- Ive seen the graphs and such.

The graphs however are two dimensional. What happens in the z-plane?? Meaning if your router is upstairs, and your wireless laptop is downstairs, does it have any effect on either the gain or range in the z-plane?

baxterdog
December 10th, 2007, 05:30 AM
Is the antenna made of aluminum or other metal? Paper wouldn't quite do it.

Lostincyberspace
December 10th, 2007, 05:36 AM
You would probably coat a paper with aluminum foil.

n3tfury
December 10th, 2007, 12:43 PM
Is the antenna made of aluminum or other metal? Paper wouldn't quite do it.

in the OP's link, it clearly states to glue tinfoil to the surface.

Envirotech
December 12th, 2007, 04:36 PM
I used the antenna from the original post. I used stiff construction paper and a large piece of aluminum foil glued smooth. It took a couple of tries with the foil to get smooth. I was not sure it would matter so I made sure it was and it worked great. I do not have a z -axis in my situation. no basement in the house with the router. If this did not work I was going to try the pringel can antenna.

http://www.turnpoint.net/wireless/cantennahowto.html
http://www.oreillynet.com/cs/weblog/view/wlg/448
http://www.turnpoint.net/wireless/has.html

Are some examples of them.

n3tfury
December 12th, 2007, 05:30 PM
i might do one of the waveguide antennas. nice!

satx
December 13th, 2007, 01:18 AM
kevdog:

Rotate the two-dimensional graph about it's axis and you will get a reasonable idea of what happens. See attached image.http://www.freeantennas.com/projects/template/pat9_inch.jpg

kevdog
December 13th, 2007, 04:27 AM
Thanks for the graph

I thought it was rule of thumb to locate the router higher (rather than lower) as compared to the location of the wireless client. Based on the graph you linked to, this would not seem to be the case, since the broadcast signal would be equivalent in the +z and -z axis.

Is there any truth to this rule of thumb?

satx
December 13th, 2007, 02:17 PM
kevdog:

If you are using the normal antenna (dipole) then you have one radiation pattern. This changes if you have converted the dipole to a parabolic reflector. See:

http://en.wikipedia.org/wiki/Dipole_antenna

satx
December 13th, 2007, 08:39 PM
Envirotech-

Great references on antennas. If we keep this thread going we will all be experts on antennas!

Prior to getting into computers 25 years ago (yes, I am an ol' fart), I spent 11 or so years in the microwave business (designing microwave power transistors), so I really get into optimizing hardware perforamance. A couple of years as an early CB radio user also helps.

Let me know if you are planning on building other antennas, etc.

SATX

bodycoach2
January 15th, 2008, 12:49 AM
I have made many of these Windsurfer antennas for some Free Geek Central Florida receipients. In my own house, the signal would drop off so bad in my bedroom, the wireless wasn't really doing anything for me. After adding the Windsurfer antennas to just the router, I could get full signal in the bedroom. I got curious, and I can get 80% signal three houses away, 50% signal five houses away, but I can still get 30% signal 10 houses away.

This things actually works.

kevdog
January 15th, 2008, 02:36 AM
Great to know -- still havent gotten around to making mine yet, although I bought some stiff slide transparencies to use as the backing to put aluminum foil over.

Hopefully that will work!