Got my pigtail from Webb Industries

I was on a site with a calculator that took the base diameter and ghz you would like to pick up on it and it worked out 120mm (note, 1.2cm) from the base

I see the real cantenna for pringles does some sort of modification of the top part (where you close the can)

I have no such modification, will read a bit more but i'm too lazy, work has been a bitch and i am it's slave
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by noone</i>
<br />I was on a site with a calculator that took the base diameter and ghz you would like to pick up on it and it worked out 120mm (note, 1.2cm) from the base

I see the real cantenna for pringles does some sort of modification of the top part (where you close the can)

I have no such modification, will read a bit more but i'm too lazy, work has been a bitch and i am it's slave


<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

correction, i placed it at 1/4 wavelenght, which is about 6.25cm from the base... hell, i guessed that far, so its pretty amazing, could go a bit forward though (about 6 cm from the base)
 
1 Wavelength = (300 / center frequency 2510) = 119.5 mm (not taking velocity factor into account)
1/2 Wavelength = 119.5 / 2 = 59.75 mm
1/4 Wavelength = 119.5 / 4 = 29.88 mm

Remember at these frequencies 1 mm out could resonate your antenna way off the required frequency and cost you dB's [:)]



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this is getting confusing

29.88mm??????

the website that tells you how to build it says 6.25cm, another website says 120mm

screw you guys

i'm going home
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">correction, i placed it at 1/4 wavelenght, which is about 6.25cm from the base... hell, i guessed that far, so its pretty amazing, could go a bit forward though (about 6 cm from the base)<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Noone, that's about right! The website http://www.turnpoint.net/wireless/cantennahowto.html and my book showed it must be around 7 cm from the base given 2.5 GHz frequency.
Remember the wavelength in the can is longer than in air. That's why its called the guide wavelength or lambda_g.
 
For some pigtails check out this site

www.rflinx.com/Cables-Connectors-LAR/Cables.htm#18%20Pigtails

Found no reference to Ipwireless on the site tho [V]
 
What difference does the diameter of the tin make, i see the pringles tube is 7cm, i found a very nice solid metal tin at the bottle store yesterday, it's an Amarula tin, the diamater is exactly 9cm and i get the bonus of drinking the Amarula :P

Will it being proper metal make any difference to the strength as well ????
 
The diameter effects the overall volume of the can, the wider the diameter, the closer the N-connecter sits inrelation to the base of the can, smaller diameter=Longer Length =&gt; different pos from base.
Thats also why some people are getting calculations of 6mm, others at 12mm etc, the length changes exponentially in relation to diameter.

Can we try to standardise one thing, the connecter protruding into the can should be around 30mm long for 5 GHz, anyone got different calculations on that?
 
The connector at 30mm is just fine. That's stock standard for the 1/4 of the wavelength, and doesn't change.

I've gotten hold of a little program that can print optimized funnel designs on paper, as a template. Haven't tried it yet tho.

It's called HL_ANT, just google for it.

I've tried a 750g Frisco can now. It's much smoother, and has a completely flat bottom too. Reception though, was pretty much the same as what I got with a ribbed milk forumala can.


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<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Sliver</i>
<br />Will it being proper metal make any difference to the strength as well ????
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As long as it conducts electricity well (not on the oxidized surface, but on the inside), it should make no difference.

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">for 5 GHz<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
2.5 perhaps ?

The connector at 30mm is just fine. That's stock standard for the 1/4 of the wavelength, and doesn't change.
I disagree... A wave in a channel travels slower than in an open medium. If you consider a wave as infinitely many particals, you'll soon see that they do not all follow a straight path. Instead they bounce off the sides of the channel and zigzag.

Actually you should be able to make an antenna on this principle : Instead of letting the waves bounce off smooth surfaces, you can place a properly designed metal grid in front of the aerial. The wave change direction as some of the wavefront is delayed by it. This causes all the waves to converge at the focal point.
Click to expand...
Click to expand...
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">The connector at 30mm is just fine. That's stock standard for the 1/4 of the wavelength, and doesn't change.
I disagree... A wave in a channel travels slower than in an open medium. If you consider a wave as infinitely many particals, you'll soon see that they do not all follow a straight path. Instead they bounce off the sides of the channel and zigzag.
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I think Rodent and Dorris are talking about the length of the pin that's protruding into the can, not the distance of the connector/pin from the base of the can.
The length of the pin should be a quarter free space length i.e. 30 mm, see
http://www.saunalahti.fi/elepal/antenna2.html

Ajax
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Rhino</i>
<br />I get pigtail on monday.............hopefully..... but mine is 1.2m @ R93.50+vat [8D] so I wont need a extension. PROASM: Any closer with overport base?
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Did you get this pigtail yet ?? does it fit ?
 
hmmmmm surprise surprise, Now the cable will only be shipped on wednesday. There was a "problem" with the connector. They need to confirm that it was the correct 1 that was fitted *sigh* Guess I will just have to wait then...
 
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Rhino</i>
<br />hmmmmm surprise surprise, Now the cable will only be shipped on wednesday. There was a "problem" with the connector. They need to confirm that it was the correct 1 that was fitted *sigh* Guess I will just have to wait then...
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Rhina you can still buy the "patch antenna" for R260. The connector doesn't fit 100% tight into the modem, but who cares, it worx.

The problem however is the lenght of the cable. The max you get is 2.5M. I get pretty good signal on my roof, but unfortunately the cable is to short to run it down to my PC inside the house. Does anyone know where I can get an extension for this patch antenna? And what do you call this cable?

Any help will be appreciated!

CW
 
The problem with extending the actual antenna cable is the signal loss you will get over such a long cable. The best thing you can do to resolve this is to have the modem as close to the antenna as possible and either have a switch with the ethernet cable or a spare box acting as a router with the usb cable and running utp the rest of the way.
 
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