Understanding Copper/Fiber Media Converters

August 28, 2013 at 10:00 AM

What is a Media Converter?

 

Diagram of fiber optic premise wiring converted to copper with media converters

A media converter is used to extend Cat 5e/6 Ethernet cabling to distances beyond the 100 meter maximum for Ethernet by converting IP voice/video/data signals to fiber optic cabling.

 

Where are Media Converters used?

 

Media converters are used in environments where EMI/RFI is present, such as manufacturing facilities and other industrial environments. Other applications include campus networks where many buildings need to be connected via fiber. Also, high-rise buildings typically use a fiber backbone, which is laid vertically and taps into copper (UTP) networks on each floor via a media converter.

 

L-com's Media Converter offering

 

L-com offers media converters designed for both commercial and industrial use.

 

Commercial-grade fiber-to-copper media converters from L-com

 

L-com Ethernet Media Converter 10/100TX to 100FX MM SC 2km

- Plug-and-play installation
- Rugged metal case ensure longevity
- Multimode and Single-mode versions available
- Easy-to-read LEDs provide at-a-glance system status information
- Operating temp: 0°C to +70°C 

 

Industrial DIN Rail Media Converters from L-com

 

LCMC Media Converters

- 35mm DIN rail mounting
- Rugged aluminum case
- 24V DC power input
- Plug and play
- Operating temp: -40°C to +70°C

 

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.

Low Loss Coaxial Cable for Wireless Applications

June 26, 2013 at 10:00 AM

 

Closeup of Low Loss Coaxial Cable Stripped to Show Components

Even in a wireless network, cables and wires are still used to connect components together (access points to amplifiers, amplifiers to antennas, etc). Each component needs cabling to interact.

 

If you are a wireless engineer and need to interconnect components, chances are you are using low loss coaxial cabling. While 50 Ohm RG-style coax is sometimes used, the attenuation is usually too much for any length over just a few feet. This is where low loss coaxial cable comes in.

 

 

Coaxial Cable and RG-Style Coax

 

All coaxial cable works the same way: the signal is run over two "axes" (thus the name). Coaxial technology is one of the oldest signal cabling types, and is still used today for a specific reason: it is robust and can carry a signal very well over a long distance. In general, the thicker the cable, the less "loss" or attenuation of signal there is over the length of the cable.

 

The original standards for coaxial cable were set forth by the US military. These cables used the term "RG" (for "Radio Guide" or "Radio Government") followed by a number to designate the standard. This worked well at the time, but as technology became more and more utilized in commercial and non-military applications, the restrictions of the standard became less rigid (to the point where RG316, for instance, may have very different properties today depending on who manufactures it).

 

 

Times Microwave LMR® Cables

 

No matter who makes the RG-style cables, they have one fundamental problem: the signal degrades over the length of the cable until it is no longer useable. For shorter use in labs or machine-to-machine applications, this is not a problem. But in wireless applications, the signal integrity up until it is broadcast through the antenna is critical.

 

For that reason, Times Microwave Systems developed a low loss version of coax that it branded as its LMR® series coax. The newly-engineered solution offered far lower loss and better RF shielding, making them a much better choice for wireless systems than the RG styles.

 

Outside of Times Microwave Systems' product (the term LMR® refers specifically to Times Microwave Systems product and is trademarked for their use), several other companies now offer low-loss coaxial cables. These generally follow a similar naming convention as what Times Microwave Systems uses: a three-digit "series" number that refers to both the thickness of the cable and the low loss properties.

 

For instance, 100-series low loss coax is thinner and has greater loss than 200-series, which is thinner and has greater loss than 400-series, etc.

Diagram of most common low-loss coaxial cables

Note that with thicker cable factors such as cable weight and flexibility must be considered. However, there are now ultra-flex versions of thicker series like the 400-series that offer similar loss characteristics but are far more flexible.

 

Quick note: L-com has been manufacturing high-quality coaxial cables and components for over thirty years.
 
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