logo
Your Ad Here

Choosing a Wi-Fi Pigtail

A pigtail acts as a converter between large diameter cables and small connecters commonly used on Wi-Fi cards. Because of the very small connector sizes, pigtails are difficult to build and require highly skilled soldering techniques.We recommend that you purchase pigtails for use in your projects. Several online stores sell pre-built pigtails in specific lengths. To purchase a pigtail, the vendor will need to know a few things:

Length of pigtail: should be less than 2 feet to keep signal loss low

Cable connector : the type of connector to plug into the larger cable (usually male)

Device connector: the type of connector to plug into the Wi-Fi device (usually female)

The device connector is specific to the type of Wi-Fi card or access point being used.



Connector Types for Wi-Fi Cards

There are almost as many connector types as there are Wi-Fi device manufacturers.Table 1-5 lists some of the most popular connectors. The MMCX, MC-Card, RP-SMA, and RP-TNC male connectors and some of the female    devices to which they attach are shown in Figure 1-27.

Finding Pigtails

Pigtails are not available in stores. They must be purchased from vendors that construct them on a regular basis. Sometimes you can find them locally at swap meets or user group meetings. Usually it’s easier to buy them online. Here are some popular sites:

www.ecwest.com

www.fab-corp.com

www.hyperlinktech.com

www.wlanparts.com

www.ydi.com

These stores generally sell antennas, wireless devices, and cables as well as pigtails.

Cheap Cable Testing

When a transmission problem arises in a Wi-Fi system, the first place to look is at the cables and connectors. Connectors generally take the most physical stress in a system, and also can be the first piece to break down while operating in poor conditions. The middle of the cable or the inside of an antenna is less likely to sustain damage if stressed when compared to the cable ends and connectors.

This is where simple cable testing can be of great value to troubleshoot a system.To check for continuity and for shorts, use the ohm-meter function on a multimeter.Test the entire length of the cable through each connector.

1. Check for continuity from center pin to center pin. This should be a short or zero ohms.

2. Check from connector body to connector body. This should be a short or zero ohms.

3. Check from center pin to connector body. This should be open or infinite ohms.

Often when you’re testing a cable, it’s already installed on-site, which limits access to the cable ends. To get around this, disconnect both ends of the cable and short the center pin to the connector body on one end only. Then measure resistance of the pin to the body on the other end.

The resistance should still be zero ohms (or very close). For the unlimited budget, products like a time domain reflectometer (TDR), spectrum analyzer, RF Power meter, and network analyzer can be used to test entire transmission systems, including the cable. These usually cost several thousand dollars to buy and hundreds to rent. If the connector is presumed bad, replacing it is often much less costly than extensive testing. And very often, the only way to fix a bad connector is to replace it and start over.

Summary

Wi-Fi is radio at microwave frequencies.Transmission lines at 2.4 GHz are more prone to signal loss and must therefore be considered an important part of the entire Wi-Fi system. A low-loss, large diameter cable and a pigtail adapter makes it easy to position the antenna for the best radiation pattern and signal strength.

Building connectors on-the-fly opens up a new realm of independence. By obtaining the cable in bulk, and the various types of connectors, it becomes a simple process to build your own custom cables tailored to each application. And the cable will be exactly as long as necessary. Read on to the next chapter to explore antennas: how antennas are defined, antenna radiation patterns, choosing an antenna, and pros and cons of high-gain antennas. You’ll even see how to build a simple omni antenna that will boost your range by up to 200 feet.