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WiFi cantenna without pigtail

WiFi cantenna without pigtail
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  • complete.jpg
  • adaptor.jpg
  • cans.jpg
  • wire.jpg
  • n-type-female.jpg
  • n-type-male-to-RPM-SMA-a.jpg
  • n-type-male-to-RPM-SMA-b.jpg
  • inside.jpg
  • connection.jpg
  • last photo ←
»
There are many websites detailing the construction of cantennas, all of them referring to a pigtail. A pigtail connects the antenna to the WiFi adaptor. However, any length of cable induces signal loss through impedance of the electromagnetic wave.

This cantenna design does away with the pigtail by using an n-type to reverse polarity male SMA adaptor. This adaptor connects your cantenna directly to a WiFi adaptor without need for a pigtail.

The microwave signal is processed in the adaptor so you can then use a long USB cable to connect from the WiFi adaptor to your computer without signal loss.

The cantenna is directional so you will need something like a tripod to direct and hold the cantenna in place. Expect about a 3dB improvement of the signal, which is roughly a doubling in power, and hopefully many more access points being revealed.

I won't go into detail about the construction of a cantenna but point you towards http://www.saunalahti.fi/elepal/antenna2.html for detailed measurements.

However, do look at the slide show to see the subtle difference that obviates the need for a pigtail.

Parts List:

High power WiFi USB adaptor with SMA connection for antenna ( I use an ALFA AWUS036H)
Can - over 76mm in diameter (Long and thin is better than short and fat)
N-type female chassis connector
N-type male to RPM SMA adaptor
Some thick unsheathed copper wire (about 1 to 1.5mm diameter mains wire is best)
Solder
Four small nuts and bolts to attach N-type female to can

Tools:

Drill and bits (cone bit to make hole for n-type chassis connector)
Soldering iron
Screwdriver
Wire cutters

You can see other self-reliant things I make and do at http://www.ecopunk.org.uk

4 comments
Dec 1, 2010. 2:44 PMwhoispetty says:
Instead of using a second adapter, could you just purchase a N-type female to RP SMA male?

Or would that not work correctly?

I'm interested in making one of these for my belkin range extender.

Here's a link to an adapter I'm talking about.
http://cgi.ebay.com/N-female-RP-SMA-male-Jack-Straight-Connector-Adapter-/160513197349?pt=LH_DefaultDomain_0&hash=item255f550525#ht_2645wt_907
Feb 11, 2010. 9:10 AMWilderbeast52 says:
I assume that this setup would be for a single computer?  Also, would the "N-type male to RPM SMA adaptor" work in place of any antenna?  Would a different adapter be necessary on some devices?

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Author:TheGoodLife(ecopunk)
Green, downsized, dropped out, lifehacking, office cubicle refugee