How To Make: CHEAP Homemade Parabolic Reflector Antenna

[-=Xploitz=-]

I was referring to the "ever-popular" super-cantenna

Price: $ 39.99

http://shop4.outpost.com/%7BxseqTgdA...H:MAIN_RSLT_PG

bought at Frys Electronics here in the States. $40 bucks... not a homebrew one..lol Anything homebrewed is usually a LOT cheaper..lol

Sorry to say I do not agree with that statement! There is no such thing as "receiving gain" and "broadcasting gain", there is only one type of gain: "antenna gain", which is proportional to an antenna directivity (both in horizontal and vertical plane) and size (in case of the parabolic).

Really? So..you wouldn't agree that if set up my AP say ..1000ft away from myself...and used both the yagi and the parabolic reflector...and compared the ability to "see" and "talk" with the AP...that the parabolic reflector wouldn't out preform the yagi?

And Yes..the parabolic does out-preform the directional yagi by a good bit. I have been able to see and talk with my AP with my parabolic reflector..when my yagi could only see it. Sorry m8...but thats as scientifically approved as my proof is gonna get.


***EDIT***
BTW....

Yagi or Yagi-Uda Antenna
Yagi Antenna is a directive antenna array usually consisting of a dipole, reflector and multiple director elements having gain in the 6 to 18 dBi range.


Parabolic Reflector Antenna
Parabolic Reflector antenna consists of a parabolic metal surface (dish) with a feed antenna in front. The feed antenna consists of a directive antenna such as a dipole and reflector, log-periodic dipole array or horn antenna. Parabolic Reflector antenna is capable of producing extremely high gains, usually in the 20 - 30 dBi range.


Shurley theres a reason as to why the parabolic out-preforms the standard yagi?? Must be because it "focuses" better by using the metal behind it to "bounce" the signal and focus it in the curves direction.

Again...its true "backfire" that gives it better :"receiving gain" and further "broadcasting gain" ..

I know theres no such term as "receiving gain" and "broadcasting gain"...I made those terms up to help simplyify things for the no0bs so that they would get a better understanding of how it works.

[bitza]

Hold on! I am getting confused!
This is not the statement I answered to! I only challenged your quotes of "receiving gain" and "broadcating gain" as an antenna parameter, which does not exist for a given antenna. nothing more.
I also say that parabolic gain is dependant on reflector size, and I do agree with you that a parabolic antenna will outperform not only the yagis but also any other kind, depending on it's size.The "windsurfer kind doesn't fit in this category, if it can be called parabolic. When it gets to parabolic, the bigger, the better!
All I wanted to say earlier was about gain. There is only one type of gain, measured in db. Same in both directions.

As of "receiving" or brodcasting" gain, it does exist when you want to compare WIFI cards, its called "receive sensitivity" and "output power".

Will we agree on that?

PS: Do not worry! Among all my antennas, I also have a 32" parabolic dish!...

[dapirates1]

I have a Proxim 11b/g 8471-WD card gold and 7dBi magmount aerial + 50cm adaptor cable can i use your guide to extend the range of my card do i make it as in the guide then just put it round my magmount aerial am not sure as i seen it getting used by the ap it would be good to try i would like to extend my range in my household

[-=Xploitz=-]

Hold on! I am getting confused!
This is not the statement I answered to! I only challenged your quotes of "receiving gain" and "broadcating gain" as an antenna parameter, which does not exist for a given antenna. nothing more.
I also say that parabolic gain is dependant on reflector size, and I do agree with you that a parabolic antenna will outperform not only the yagis but also any other kind, depending on it's size.The "windsurfer kind doesn't fit in this category, if it can be called parabolic. When it gets to parabolic, the bigger, the better!
All I wanted to say earlier was about gain. There is only one type of gain, measured in db. Same in both directions.

As of "receiving" or brodcasting" gain, it does exist when you want to compare WIFI cards, its called "receive sensitivity" and "output power".

Will we agree on that?

PS: Do not worry! Among all my antennas, I also have a 32" parabolic dish!...

lol..Yes..we can agree on that..lol.

Sorry for geting the signals mixed up with our conversation. No harm...no foul.

32" dish?? Wow...I bet its pretty heavy. I'm assuming you have it mounted on your roof?? Or is it one of those "light weight" ones you an be "portable" with??

[-=Xploitz=-]

I have a Proxim 11b/g 8471-WD card gold and 7dBi magmount aerial + 50cm adaptor cable can i use your guide to extend the range of my card do i make it as in the guide then just put it round my magmount aerial am not sure as i seen it getting used by the ap it would be good to try i would like to extend my range in my household

I posted a pic or 2 of my " pre-historic" (trial and error rush job) reflector I made...its on the first page. Go take a look.

BTW...your on the right track. The reflector is placed around my 10dbi omni....and the omni is placed in the center of the parabolic reflector...about an inch and a half from the metal.

[bitza]

lol..Yes..we can agree on that..lol.

I fell better!

32" dish?? Wow...I bet its pretty heavy. I'm assuming you have it mounted on your roof?? Or is it one of those "light weight" ones you an be "portable" with??

It is actually an unused "offset" direct TV dish, where I took the 10 GHZ head out to replace it by a homemade bi-quad element. It looks a little weird, because I mounted the dish upside down, the arm suporting the head being on top, so that I can adjust the dish easily for an horizontal receiving. The other advantage is that the head doesn't get too much rain that way! I can post a picture, if you are interested. The whole thing sits on my balcony, to my wife's despair..., but it is convenient to point it where I want. I am still in the process of finding the right focal point, and it's getting cold here... For the time being, I get AP's with a good signal 500 meters away, but I think this distance will rise with further adjustments. I am using the AWUS036H Alfa USB card, which is extremely sensitive (but illegal here!)

[-=Xploitz=-]

I fell better!



It is actually an unused "offset" direct TV dish, where I took the 10 GHZ head out to replace it by a homemade bi-quad element. It looks a little weird, because I mounted the dish upside down, the arm suporting the head being on top, so that I can adjust the dish easily for an horizontal receiving. The other advantage is that the head doesn't get too much rain that way! I can post a picture, if you are interested. The whole thing sits on my balcony, to my wife's despair..., but it is convenient to point it where I want. I am still in the process of finding the right focal point, and it's getting cold here... For the time being, I get AP's with a good signal 500 meters away, but I think this distance will rise with further adjustments. I am using the AWUS036H Alfa USB card, which is extremely sensitive (but illegal here!)

YES!! Plase post pix of your Direct TV hack!!! I'd love to see them.

BTW...just guessing...the focal point would probably be close to 4-5 inches out and away...maybe 6' from its center on a 32' dish.

[default]

Found this page ages ago, gives plenty of ideas for reflectors:

http://www.exe64.com/mirror/wokfi/

[streaker69]

Found this page ages ago, gives plenty of ideas for reflectors:

http://www.exe64.com/mirror/wokfi/

All of their measurements are suspect because they chose not to use a supported card with Netstumbler to get proper SNR readings.

[bitza]

YES!! Plase post pix of your Direct TV hack!!! I'd love to see them.
BTW...just guessing...the focal point would probably be close to 4-5 inches out and away...maybe 6' from its center on a 32' dish.

Thanks!
I finally was able to check the focal point by beaming it to the sun! Had to wait for a sunny day, and they are getting scarce here...I in fact moved the source closser to the dish by two mm. I took the opportunity to take sunnier pictures of it, too...so here we go!
1) Side view. You will notice that it is mounted upside down, the arm on top. Like it is, it points in an horizontal direction.

Attachment 183


2) Side view of the source. Before you ask, I am using semi-rigid coaxial, where the outside braid is in fact a silver coated copper pipe (8mm)! It takes some efforts to bend it to shape, but losses are close to zero!

Attachment 184

3) And finally detail of the biloop source and it's reflector. I used galvanized steel, but I am planning on replacing it by copper:

Attachment 185

As for the Quad biloop I made, here are also some pictures: (well, it seems I am limited to five pics, will post the other three later if you are interested)
Front view without cover:

Attachment 186

and rear view:

Attachment 187

The coaxial I am using here is also semi-rigid coax (RG-402, if I remember correctly), but easier to bend as it is only 3.6mm in diameter.
On both antennas, I put the USB WIFI key right on the antenna's "N" connector, through an adapter to minimize coax losses. I prefer using long USB cables.

I do not really understand streaker69 comments about the fore-mentioned antenna page, especially about improper SNR with some cards and Netstumbler? To me, signal to noise ratio only characterizes an active circuit (amplifier, receiving front end, etc), but not a passive element such an antenna. An antenna is measured by it's gain in all directions, and it's SWR, by professional tools on a test range, the results being the logarithmic circular charts shown on that site. Netstumbler could only be used as a signal comparison tool between a know gain antenna and an antenna under test. At that point, SNR is irrelevant, signal power is the only interesting figure. BTW, I also use WIFI-hopper for that purpose, which is in some aspects nicer to use, gives more info, and allows to connect to an AP, although I do not like too much it's "automatic expanding signal window" and prefers Netstumbler's strength meter and the possibility to magnify as you like. Also latest release of WIFI hopper is 2007, Netstumbler 2004...W're all aging!...