Hi,
The distance depends on which type of element you created. I showed the
difference on measurements for using a wedge or pole/wire element. The
cantenna we built and took pictures of used a wedge element. So, in the text
and the photographs, we measured for 27mm. But if you use a pole-type you
will be around 44mm (give or take depending on your center frequency).
So, if you have a little sticky uppy radiating element, drill at 44mm. If
you made a little pie-wedge flat element, drill at 27mm. (I tried to get
that in the original copy, but they came back with "is sticky uppy the
technical term?")
Share and enjoy!
-Mike
-----------------------------------------------------------------------
Wi-Fi Toys PAGE65 [excerpt]
Where to Drill
We will be using a copper wedge as the driven element or radiator. The
location and length of
this element is extremely important. Although we will not be going too deep
into the math
here, it's important to understand where this driven element is to be
installed.
The rule of thumb is that the driven element should be at one quarter of the
"closed-space
wavelength" from the inside edge of the can when the connector is installed.
The difficulty here
is that the closed-space wavelength will vary based on can and radiator
dimensions.
Table 3-1 shows some of these dimensions for channels 1, 6, and 11 using two
different
types of radiators. A narrow-band pole, and wideband wedge. The wideband
wedge needs
to be built only for channel 6 because it operates well across the entire
Wi-Fi range of
frequencies.
On our can, with an inner diameter of 100 mm, this offset was slightly more
than 1 inch or
27 mm. Once you have this measurement, it is time to prepare the hole in the
can where the
N-Connector is to be installed.
Remember to measure this carefully, because a mistake means you need to buy
and use more
coffee.
-----------------------------------------------------------
Table 3-1
Radiator Offset: Distances From Back of Can to Drill-Point
-----can diameter----
Radiator freq 90mm 100mm 110mm
---------- ----- ----- ----- -----
Round ch 1 2.412 53 mm 45 mm 42 mm
Round ch 6 2.437 51 mm 44 mm 41 mm
Round ch 11 2.462 50 mm 44 mm 40 mm
Wedge ch 6 2.437 29 mm 27 mm 26 mm
-----------------------------------------------------------
-----Original Message-----
From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf
Of Chicago D
Sent: Monday, May 28, 2007 4:20 PM
To: SOCALWUG
Subject: [SOCALWUG] Re: Wi-Fi Toys --- please bear with me
Very Nice. Thank you for the input.
The N-Female connector chassis mount style arrived in the mail... less
the four screws. Not so sure how to attach it now.
But my question is in relation to where to drill. On the 100mm
diameter Maxwell House tin can, pg. 65 it says drill at the 27mm/ 1
inch mark... but then the table following as well as the picture
indicate a drill at the 44mm mark.
Which one is it really?
thanks again.
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