I have been having difficulty with my wifi connection since my computer was located too far from the router. I became interested in ways to extend the range of the router. There are a number of commercially available directional antennas that can give extend the range of the connection. I was however interested in attempting to build my own antenna, having been inspired by wifi-shootout contests that I have read about. After doing a bit of research, I felt that I would best be served by some form of a “cantenna”.

As I set out to construct one, I went looking for a connector that would allow me to connect a cable to my wifi network card that was installed in my computer.

I didn’t recognize the type of connector that was in the card. I browsed the drawers of RF connectors available at Radio Shack but I couldn’t find anything like it. I then went and looked around online, but the connector was unusual and I was having difficulty finding one like it. The unusual thing was that the center pin was in the equipment connector. That would normally make it the male connector, but it had outward facing connector threadings, which are characteristic of female connectors.

After further online research, I found that this is what is called a Reverse Polarity SMA (RP-SMA) connector. I read that this type of connector was used by manufacturers since the FCC did not want the connectors to wifi equipment to be standard so that it would make it inconvenient for people to attach non-FCC approved amplifiers and antennas. It seems that this effort has since been abandoned and it is quite easy to find RP-SMA connectors online through several suppliers. There does not appear to be a consensus on which side of these reverse-polarity connectors should be called male or female.

I was able to find a RP-SMA to type-N male pigtail on eBay. I also purchased on eBay a type-N female bulkhead connector for attaching to the cantenna.

I will be attempting the design show here, but I still need to find a suitable sized can.