Access Point (AP) Antenna Replacements

August 21, 2013 at 10:00 AM

 

Upgrading the antennas on your WiFi access point: How to determine the correct AP connector

 

Our technical support department often answers questions like: "How do I upgrade my access points' antennas?" or "How do I identify the type of connector on my WiFi access point or router?" There are a few simple steps to adding or replacing the antenna on your wireless product.

 

First you must check to see if the antennas on your access point are removable.

 

                               Front of an EnGenius wireless access point (AP) showing antennas behindBack of an EnGenius wireless access point (AP) showing antennas

Front and back of a WiFi Access Point showing removable rubber duck antennas installed

 

Back of an EnGenius wireless access point (AP) showing antennas removed

Back of a WiFi Access Point showing rubber duck antennas removed.

 

Next you should identify the type of connector the antenna jack is on the access point. One tip is to check with the manufacturer's website or user manual for your specific make and model listing for the antenna connector type. If you cannot find it on the manufacturer's web site, you can compare it with our common RF connector chart shown below.

 

Common RF Coaxial Connectors

 

Also, you may want to upgrade to a higher gain rubber duck antenna on your access point to increase the signal range and strength. View our 2.4 GHz Rubber Duck antenna selection.

 

Or you might want to connect your access point to an outside antenna. In this case you will need to connect a low loss coax pigtail cable to your access point and then to a longer antenna feeder cable to reach the outside antenna as illustrated below.

 

Illustration of low loss coax pigtail used to connect wireless AP to an antenna

Quick tip: If you need a new antenna, try L-com's Antenna Product Wizard to make your search easier. The wizard will walk you through three steps to identify antennas that match your criteria.

Tips for Buying Coaxial Cable

August 14, 2013 at 10:00 AM

 

What’s right for your application?

 

Selecting the proper coaxial cable can go a long way toward satisfying the needs of a specific application. Which criteria are most important to the specifying process? There are 4 key points to be considered when choosing coaxial cables:

 

      RG174/U Bulk Coaxial Cable - Flexible Small Diameter 50 Ohm Cable

 

 

 

 

 

 

1. Cable Type

 

There are basically two types of coaxial cables: those with an impedance of 75 Ohms (Ω), used mostly for video applications, and those with an impedance of 50 Ω, used mostly for data and wireless communications.

 

Typical 75 Ω cables are our RG59/U and RG6/U. These cable types are available in 100-, 500- and 1000-foot reels.

 

Typical RG-style 50 Ω cables for data are RG174/U, RG188/U and RG316/U. These bulk cables can be used in applications where cable assemblies must be built in the field. Available in 100-, 500- and 1000-foot rolls, their stranded 26 AWG center conductors result in very flexible cables for tight-fit applications. Additionally, the bulk RG188A/U cable has a Teflon-taped outer jacket to help achieve a 200-degree C operating temperature, and the RG316/U has an extruded FEP outer jacket that helps achieve a 200-degree C operating temperature.

 

50 Ω cables are also available in the low-loss version: 100-, 200-, and 400-series specifically for wireless applications. Low Loss coaxial cables provide far better shielding than their RG style counterparts and are best suited for RF applications.

 

 

2. Operating Frequency

 

Another important consideration is the operating frequency of the signal carried on the cable. As the frequency increases, the signal energy moves away from the cable's center conductor to the cable's shield outside of the conductor, a phenomenon known as the "skin effect".

 

This has a direct correlation to how far the signal can travel over a cable of a certain length, for a given signal frequency and power level. The higher the signal frequency, the shorter the distance traveled.

 

For our full Coaxial Cabling Tutorial, click here.

 

 

3. Cable Attenuation

 

Cable attenuation is the amount of signal loss over a specific distance. In general, the higher the frequency, the larger the attenuation will be. The larger the diameter of a cable's center conductor, the lower the attenuation is.

 

For example, an RG59/U cable with a 14 AWG center conductor can carry a signal (at a specific frequency and power level) about twice the distance as that of an RG11/U cable with a 20 AWG center conductor. It's imperative to know how much cable attenuation is acceptable in your particular application when selecting coaxial cable.

 

 

4. Characteristic Impedance

 

A coaxial cables characteristic impedance is an important parameter that affects the performance of the signal being carried over the cable. Also known as transmission impedance, it is defined as the relationship between a cable's capacitance per unit length to its inductance per unit length. For optimum signal transfer, the cable's characteristic impedance should be matched to the impedance/resistance of the load.

 

RG59A/U Bulk Coaxial Cable - Stranded Center Conductor 75 Ohm Cable
50 Ohm BNC Crimp Plug for RG58 - Amphenol #31-320-RFX
See a Matrix of Data
and Wireless Coax Cable Assemblies for Easy Ordering
Looking for bulk 75Ω cable for audio/video? See it here!
Get Coax Connectors
from L-com and build your own cable assemblies!
 
Quick note: RG-style coaxial cables are not all built the same. Check the specification requirements before you buy, and if you need help contact our technical support.
 

What Does MIMO Mean?

August 7, 2013 at 10:00 AM

Multiple-in/Multiple-out Antennas (MIMO) Explained

 

MIMO Panel Antenna Showing Multiple Coaxial Lines

Most antennas have worked very simply: a frequency transmitted from one antenna could be picked up by a antenna tuned to receive it a distance away without the need of cables between them. While this basic description of a wireless system works, today we have many ways to improve upon the basic concept to increase things like redundancy and coverage. One of those methods is MIMO, which stands for multiple-in multiple-out.

 

MIMO antennas are actually several antennas all within a single physical item or radome. They co-exist either by working in different bands (as the IEEE standard 802.11n works, in both 2.4 GHz and 5.8 GHz) or different polarities, or both. By breaking the data into separate signals and broadcasting them over multiple antennas, MIMO systems can pick from the strongest signal no matter what the environmental conditions.

 

If you have a radio, access point, router or other wireless device that uses MIMO transmission, you will usually see separate jacks for the different signals. Likewise, a MIMO antenna will have multiple jacks or cables to hook up. Once they are plugged in, the antenna takes advantage of a phenomenon called "multipath", which refers to the way multiple signals bounce off of objects and arrive at the receiver at slightly different times.

 

Quick note: L-com's HyperLink® MIMO antenna product center includes options for many popular bands and antenna types.

Cabling for LAN and Premise Architecture

July 31, 2013 at 10:00 AM

 

Diagram of Wiring Closet Rack

It's hard to fathom just how quickly Ethernet technology has grown. Today no modern office building would be functional without premise wiring, or the cabling run throughout the building to connect computers to the LAN.

 

We may be on the verge of a wireless revolution with new technologies like DAS and MESH, but for now you should at least understand the basic architecture of LAN cabling.

 

LAN wiring is often broken into three types: backbone, horizontal runs, and patch cabling, each with its own purpose and requirements. In an especially large building or in a campus of buildings, the backbone is the wiring that connects server locations together and to the Internet through an ISP. Since a large amount of data may be carried back and forth by these cables, they are typically designed for bandwidth, like T1 lines or fiber optic cables (usually multi-fiber lines like breakout or distribution style, or even ribbon fibers).

 

Close Up View of Solid Conductor Category-rated Cable

The horizontal runs are the individual cables coming from the servers to the Work Areas. Work Areas are the points where the cable is terminated in a wall plate or jack so a user can plug their computer or other device into it.

 

It is often deceptive to assume that a single horizontal run will connect to a single computer. More likely than not, it is connected into a local Ethernet switch or wireless access point, and many computers may be connected to that. For this reason, the actual data carried on a single horizontal cable could vary greatly, and if you are planning your LAN architecture, this is the trickiest thing to get right. It can also be the most expensive piece to change if you get it wrong as you may need to fish the cable back out of a wall or conduit to re-arrange it.

 

Horizontal runs are currently most often solid-conductor Category rated copper cable. This is slowly changing over to fiber optic cabling as the price gap between the two narrows and fiber optic technology improves. Note that the horizontal cable may also require special jacket types to comply with building fire codes.

 

Right Angle Ethernet Cable Assembly

The patch cabling in a LAN is often overlooked, but is also very important. In general it is used to connect two devices together in a rack in a server room, or to connect a device to a wall jack where a horizontal cable is terminated. Being exposed (not behind a wall or on a rack ladder) and possibly being moved frequently, a patch cable needs to be robust and flexible.

 

While patch cables are easily available and can be bought relatively cheap, you might want to consider that cheap cables may introduce problems to your LAN. Cheap cables often use substitute materials such as copper clad aluminum or feature low quality plugs not rated for the application. Cheap cables seldom pass the testing required for the network and will degrade your network performance.

 

With more devices requiring power (POE), the cheaper cables often cannot carry the added burden due to undersized conductors and low grade copper. For a single user's computer, the impact of this may be limited, but in a server room low quality cables can have a disastrous effect on the entire LAN. If the cable manufacturer you purchase from has a robust QC process, it will help.

 

Other features to consider are molded right angle connectors to ensure the connector isn't bent to fit into limited space, cable boots to make depressing the connector latch easier, and high-flex construction and oil resistant jackets for demanding environments.

 

L-com stocks components for every facet of your LAN, from Ethernet cables, plugs and jacks, to bulk copper or fiber cable, to active media converters. We also go beyond that, to reliable racks, panels and cable management accessories, lightning and surge protectors, Power-over-Ethernet components and everything for wireless deployment.

 

How to Install Grid Antennas

July 24, 2013 at 10:00 AM


Grid Antenna Mounted on a Mast or Pole with Downward Angle

To make installation for your application easier, here’s a rundown of what to look for. First though, let’s decipher this: why use a Grid Antenna?

 

For point-to-point communications, a grid antenna has a lot of advantages that may make it the best choice for your application. First- since they are directional, they can provide better gain by focusing the beam in a particular direction. Second, though they are typically larger than other antenna types, they usually break down easily to fit in a box for easy transport to the installation site, or for storage while not being used.

 

Once assembled, the grid provides better wind loading than dish antennas. They are very also very easy to mount in either vertical or horizontal polarization and easy to tilt for precise aiming.

 

 

Assembly

 

We suggest double-checking the quality of the antenna before you purchase, especially if the installation is outdoors. The grid should have a UV protective coating and all of the hardware should be stainless steel.

 

When you order a grid antenna, it usually comes disassembled. Different manufacturers make grid antennas with slightly different installation instructions. When putting the grid antenna together, take all normal safety precautions to avoid coming into contact with dangerous electrical lines, etc., then go over the parts list. All grid antennas need the grid itself (often broken into two halves to reduce shipping costs), mounting "L" bracket, mast clamps, hardware such as screws, nuts and washers, and the feed horn. The feed horn is the long, protruding piece in the center of the grid that sends the actual signal. The below video (or this tutorial) demonstrates step by step assembly of the grid antenna. 

 

 

Where can you find a reliable antenna? L-com's HyperLink® line of grid antennas features tons of options for 2.4 GHz and 5.8 GHz bands, along with specialty versions for the 900 MHz, 1.9 GHz, 3.5 GHz and 4.9 GHz. Many options are available in convenient 5-packs that save you time and money. There are also hardware packages for replacing or maintaining components of a grid antenna.
 
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