 fredsimonTruly YoursPremium
join:2001-07-02
Ardmore, PA | reply to stimulation
Re: These Ducks Quack !!! The world is really a small place and those of us who do this kind of stuff tend to be a tight knit community. Often we may not agree on some things, but we remember the folks who not only stuck the umbrella up the wrong place, but then opened it before the pulled it out. People get real upset when you borrow their ideas. Not a good way to get help, and a worse way to make friends.
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Without the spice of risk,the taste of victory is bland.~FRED~ |
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 dandemanPremium,MVM
join:2001-12-05
Chapel Hill, NC
 ·AT&T Southeast
| reply to rahlquist
quote:
Personally I dont think anyone should be worrying about making a profit on ebay on these things, lets just enjoy using them.
Agreed.. I think there's more fun and general interest in everyone learning a little more about antennas and getting the opportunity to do some hands on experimenting..
As shown, the materials needed aren't a big deal and if you got a signal strength indicator in your wireless software, and an inquisitive, yearning to learn attitude, you got all you need..
This approach and attitude of learning, passing on knowledge to other interested folks is still a big enjoyment factor in ham radio and a huge part of it's history and reason for being.
And thanks for the link to the patent office.. Lot's of fun to poke around in there on topics of interest... |
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| reply to boomerbubba
I am not going to sell anything on ebay, do not worry.
I am just defending the fact that it is possible if one wanted to.
I agree with the two previous posts above me.  |
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| reply to ikarus1
THAT WOULD BE A VERY BAD IDEA... VERY BAD.
Sheesh! Sorry, I was only trying to be funny! Guess I better not quit my day job, eh?
Oh, and you DID get the focal point wrong.
You're right, I did. I made these at 2 am when I found this thread. A few days later I actually printed out the template to scale and reshaped the middle part that the antenna plugs into.
Frankly I don't see an improvement in signal strength over the original ones I scratched out by hand. Then again, I'm only operating about 30 to 40 feet away from the Access Point. Perhaps if I was further away the difference would be measurable.
Regardless, I'm a happy camper. Anytime I can tinker and not blow myself up--much less get favorable results--I end up enjoying myself.
Again, thanks for the tips! |
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 ikarus1Premium
join:2002-10-23
Urbanna, VA | Thank you sir for replying... I get touchy sometimes. In this case I didn't see the joke but I do understand. I might have said the same thing were the shoe on the other foot. You see I made it available to the public against the advice of council. The initial concept was to have a postivie impact upon network security. I hadn't thought of actually selling the thing until it got to be quite popular (3500 downloads last month and 2500 in December).
I'm pleased that the design worked for you. Thirty to forty feet is pretty close to be able to notice much difference. I've got two units that are about that distance apart but there is a stone wall between them and all I do is go from an 84 percent signal to a 100 percent signal.
Try the same expirement at a mile and you'll notice the difference, in a big way.
-m-
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»osiris.urbanna.net |
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| reply to DemiWebMan
said by DemiWebMan:
Anytime I can tinker and not blow myself up--much less get favorable results--I end up enjoying myself.
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psloanLudicrouse Speed
join:2002-07-29
Renton, WA
| reply to boomerbubba
Here is my quacker. Took about 10 minutes of work and see the difference between the signal strenght. Keep in mind this was measured up one floor and about 35 feet away through several walls and doors etc...
[text was edited by author 2003-02-04 19:14:16]
[text was edited by author 2003-02-04 19:18:50] |
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ikarus1Premium
join:2002-10-23
Urbanna, VA
| I think that antenna may be similar to the antenna on a WET-11 from the looks of it. You might get better results with the template for the WET-11. Then again I might be wrong.
If that antenna is about 15cm (~6") long use the WET-11 template. If it is about 9cm (~4") long use the dipole template. In either case try to center the dipole on the reflector vertically and I think you'll get a bit better results. Also a really nice smooth curve with very few irregularities will work better. These reflectors are very sensitive to:
1) Focal point. This is the HARDEST part to get just right.
2) Correct curveature. This part isn't that hard to get.
3) Vertical centering.
The focal point on this template is essentially a pencil sized cylinder and not really a "point". Since the dipole makes a doughnut shaped pattern the idea is to try to get the pattern to center on the reflector from just the right distance.
Nice work, with that unit, you have an opportunity to make an even bigger reflector. It's just perfect to be able to stand it up that way.
-m-
-m-
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»osiris.urbanna.net
[text was edited by author 2003-02-05 10:40:08] |
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psloanLudicrouse Speed
join:2002-07-29
Renton, WA | reply to boomerbubba
Thanks ikarus! What size is the original wet-11 template? I will give this a shot today. |
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| reply to ikarus1
I've got a question about the "Diversity" antenna configuration on my Linksys WAP11. I currently have each of my antennas pointed at different areas. One points to the left of the unit on the same floor and the other one points straight down to the floor below. I just can't position my Access Point in the optimum position and sell it to my wife, so I'm pretty stuck with where it is now.
My question is, am I going to have a problem once I buy another PC Card and have 2 laptops going at the same time but each of them operating in the separate areas?
I've read that the Access Point will switch between antennas for the best performing one. But, how often does it switch between the two? Anybody know?
I don't yet have 2 PC Cards to test this out but will be getting another one very soon. Thanks! |
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monkii1
join:2002-09-14
New Westminster, BC | reply to boomerbubba
I gave it a try...mind giving me some comment on how well(or bad) I did?
I went from always 1-2 bars of signal(Windows XP's) to consistance 3 bars(sometimes 4 bars) since I put it onto one of the antenna 1/2 hour ago...
I'm sure I'll make another one with material from big tin can to find out if it will get much better...afterall...the aluminum foil looks kinda bad... |
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psloanLudicrouse Speed
join:2002-07-29
Renton, WA
| reply to boomerbubba
OK, I tried the wet-11 antenna, but it did not fair to well, so I rebuilt my first antenna to remove some of the un even curve. Take a look at what netstumbler reported as my signal to noise graph. What I did was start with my first antenna enhancer, to none, then to the second wet-11 and back to the first. I think the first is giving much better signal.
On a side note, i noticed that my laptop wireless card had a firmware update that I had not applied. That also made a world of difference to the link quality. Did not change the signal though. So if you have a USR pcimca card, you might want to see if there is newer firmware.
Thanks! This was a fun experiment!
--pat
[text was edited by author 2003-02-05 17:23:09]
[text was edited by author 2003-02-05 17:24:18] |
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ikarus1Premium
join:2002-10-23
Urbanna, VA | Pat;
Nice work. Yes the dipole reflector is the best one for your setup. Reading your graph, it looks like the extra care with the first antenna netted you about 2 dB of gain.
That's nearly twice as good. 8 dB of gain is half as much gain as 11 dB of gain. I say the little antenna is a dipole most surely.
Take that same reflector and put it on a WET-11 and it will perform badly, take that WET-11 template you build and it will perform about as good as the other does with a dipole, you are getting about 10 or 12 dB of gain with the first antenna. Nothing to sneeze at and the workmanship is good.
Nice work.
-m-
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»osiris.urbanna.net |
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ikarus1Premium
join:2002-10-23
Urbanna, VA | reply to monkii1
said by monkii1:
I'm sure I'll make another one with material from big tin can to find out if it will get much better...afterall...the aluminum foil looks kinda bad...
Cool, not bad looking. Airplane cement, the kind used for modeling, will stick that foil right down on that cardboard nice and smooth. White glue works also but tends to wrinkle the cardboard unless you put something heavy and flat upon it while it dries.
-m-
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»osiris.urbanna.net |
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ikarus1Premium
join:2002-10-23
Urbanna, VA
| reply to DemiWebMan
said by DemiWebMan:
I've got a question about the "Diversity" antenna configuration on my Linksys WAP11. I currently have each of my antennas pointed at different areas. One points to the left of the unit on the same floor and the other one points straight down to the floor below. I just can't position my Access Point in the optimum position and sell it to my wife, so I'm pretty stuck with where it is now.
My question is, am I going to have a problem once I buy another PC Card and have 2 laptops going at the same time but each of them operating in the separate areas?
I've read that the Access Point will switch between antennas for the best performing one. But, how often does it switch between the two? Anybody know?
I don't yet have 2 PC Cards to test this out but will be getting another one very soon. Thanks!
Browse to your WAP's IP address and try for the weca.htm or maybe it is html page.
Select use best antenna. It will sense where it hears the client best and use that antenna to talk to that client. I don't know how fast it switches, fast enough I reckon. 
Now if you are trying to cover one area, not splitting up the antenna work like you are doing, it's best to stick with the factory defaults, which I believe is diversity.
I am sure there are others here who know more about that than I do.
-m-
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»osiris.urbanna.net
[text was edited by author 2003-02-05 19:39:55] |
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monkii1
join:2002-09-14
New Westminster, BC | reply to boomerbubba
Since my reflector isn't anything close to square, will it be better if I cut the reflector down to square?
Also, in terms of material, the more dense the metal for the reflector the better, is it true?
Is the netstumbler program psloan used for certain cards only? |
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psloanLudicrouse Speed
join:2002-07-29
Renton, WA | reply to boomerbubba
don't know much about netstubler. I just downloaded it today from www.netstumbler.com. I think it's primary use is to scan for existing wireless access points, but it was useful for me to gage my signal strength.
I used an cheap aluminum cookie sheet from safeway for my reflector. Would I gain anything from getting something thicker?
--pat |
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 bbarreraPremium,MVM
join:2000-10-23
Sacramento, CA
kudos:1 | said by psloan:
I used an cheap aluminum cookie sheet from safeway for my reflector. Would I gain anything from getting something thicker?
No, I don't think so. The "skin effect" of microwave radiation keeps the radio waves at the surface of the metal. I remember in my college microwaves class we made a waveguide using the metal coated wrapper from a stick of Juicy Fruit gum!
I couldn't find my old electromagnetics or microwaves textbooks so a quick Googling turned this up:
The microwave currents flow in a thin surface layer of thickness about a "skin depth" from the surface. This is because electric fields cannot penetrate perfect conductors, and only penetrate real lossy conductors a little way. See the text by Kraus on Electromagnetics for a treatment if you like.
source: »www.ee.surrey.ac.uk/Personal/D.J···ves.html |
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bbarreraPremium,MVM
join:2000-10-23
Sacramento, CA
kudos:1
| Theory behind this antenna design Want to understand the equations on M. Erskine's website? Mathematically inclined?
With reference to the hand drawn template on »osiris.urbanna.net/antenna_desig···emplate/ you can find the gain calculation on page 22 and the k=0.65 on page 25 in this paper:
»www.ece.mcmaster.ca/faculty/geor···_L14.pdf
I'm still searching for the half power beam width equation.
Interesting to note from the pdf of Prof Georgieva's class notes that the first reflector system was made by Hertz in 1888 (cylindrical reflector fed by a dipole). Sounds like the antenna design in this thread.
[text was edited by author 2003-02-06 15:06:36] |
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| reply to boomerbubba
RE: These Ducks Quack!!! Hey Boomerbubba,
What materials did you use for yours? What would you recommend? Anyone else care to share there materials list.
Thanks,
FTBoomer
www.ssbn640.com |
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