How to Utilize an RF Splitter

February 6, 2014 at 10:00 AM

 

True or False: Will an RF splitter help connect more than one antenna to a single radio?

 

The answer is true. This question commonly comes up at our technical service department so we wanted to share the facts with you.

  

A Radio Frequency (RF) Splitter/Combiner is a transmission component which divides or sums power between two or more ports. Typically they are used for connecting more than one antenna to a single radio and can also be used to connect multiple radios to a single antenna using the same frequency.

 

Generally most RF splitter products are 2 way, 3 way, or 4 way, and can split a variety of RF signals. At L-com, we offer RF splitters for 900 MHz, 2.4 GHz, and 3.5 GHz, 5.4 GHz, and 5.8 GHz WLAN applications. Additionally, we offer wideband 750 MHz to 2.4 GHz RF splitter/RF combiners which are ideal for DAS applications.

 

RF splitters have weatherproof construction and can be installed indoors or outdoors. These flexible splitters can be used with amplified systems since they will pass DC power to all ports. Remember as always, the type of RF splitter you need would vary depending on your application.

 

The following are some examples of an RF splitter in action:

 

 

 

By using a 2-way splitter in an application that requires wireless coverage on two sides of a building, a single radio can be used to feed two separate antennas covering two sides of the building.

The corner mounting bracket used in this design example is available for purchase.

  

 

7 Deadly Counterfeit Cable Sins for You to Avoid

January 30, 2014 at 10:00 AM

 

 

What scares you more than a faulty, over-rated, counterfeit cable? If you’re like us and work with cables on a daily basis, then you know the answer: nothing.  

 

Shockingly, unscrupulous sellers have found many ways to cut costs on cables, drawing customers in for the low price. But what they don’t tell you is that it comes at a price- sacrificing safety, performance, and network stability.

 

So how do you identify them? Counterfeit cables are bulk cables or cable assemblies sold under false pretenses to undercut legitimate manufacturers.  Usually this means the cable specification does not match the actual product construction. Or it could be that the seller falsely implies that a cable meets a particular performance standard or flammability rating such as Category 5E or CMP/Plenum.  If you get a low bid for your next cable quote, check these factors to make sure you are getting what you are paying for:

 
 
1. Substituting steel or aluminum for pure copper: copper-clad-steel (CCS) or copper-clad-aluminum (CCA) are classic methods of saving on costly copper needed to make cables. Over the length of the cable, however, the signal integrity will drop below the noise and cross-talk levels. There's a good reason the EIA/TIA has not approved CCS or CCA cable for use in high-speed networks…

2. Deceiving Connector construction: This is a two-part deception. For "RJ-45" (8p x 8c) connectors, rejected molded plastic bodies can be re-ground back to pellets, added to new plastic, and then made in new bodies, which can lower the combustion rating for the overall connector. A good tip: check the connector body for foggy or yellowing plastic. Aside from the body, the metal contacts are first coated with nickel then with gold to ensure a good connection. Manufacturers have been skipping the nickel and skimping on the gold, sometimes called gold flash or selective plating. Contacts made this way will eventually corrode and fail to connect when mated.

3. Cable Jacket Material: For those applications that require CMP or CMR flammability rating, the requirement is critical. If it is specified that the cable meets CMP or CMR ratings (per the NEC code) and you get an unusually low bid, ask for proof of the jacket material. A legitimate business will offer a signed Certificate of Conformance (CoC) for the product they sell.

4. Selective Electrical Performance Testing: Some manufacturers will claim their cable or cable assemblies were "Fluke tested", but won't clarify that they only ran the channel test, not the full patch testing. Patch testing is difficult to pass and more expensive, but legitimate manufacturers will do it because it ensures the cable conforms to standards and is worth what they are charging.

5. Misleading Cable Markings: All cables sold in the United States will use a UL "E-file Number" or the manufacturer's name and model number that you can look up on UL's database. The problem is that the marking may conform to UL's standard, but the cable may not. Again, a signed CoC will protect against counterfeits so make sure you get one!

6. Wire Gauge Changes: Often 25 or 26 AWG cables can be mislabeled as 24 AWG. If you require 24 AWG, you should always request a sample cable, cut it open, strip the insulation off of the wires and measure them. Don't trust a manufacturer that claims something they aren't selling; if they are untruthful about the wire gage, what else could they be hiding?

7. The Golden Sample: While it is a good idea to get a sample up front, many manufacturers will make a "golden sample" to be perfect for what you need, sometimes at great expense. When it comes time to manufacture the rest, they scrimp and cheat all they can to deliver under cost. You should always set up a system whereby you QC some of the cables in each shipment-and without the manufacturer's prior knowledge.
 
 
This problem is much more common than you think!
 
L-com found counterfeit cables from both big and small manufacturers, and from both domestic and oversea sources. “Made in the USA” means nothing if the cable is made with poor components in order to offer a cheaper price. If price is your priority, someone can always make a cheaper cable. It doesn’t matter where a cable is made, but how the cable is made.
 
The key is to know that your seller or manufacturer (like us!) is checking cable assemblies, insisting on proving UL compliance, testing their cables, and always meeting standards. At L-com our Ethernet cables are made in our own factory versus in a sub-contractor’s, guaranteeing superior quality every time. 
 

The ISM Band Frequency Dilemma: Which One is Right for You?

January 23, 2014 at 10:00 AM

 

The FCC allocates different frequencies for different purposes, and each has its own advantages. In the US, 900, 2400 and 5000 MHz frequency bands are set aside by the FCC for unlicensed Industrial, Scientific and Medical (ISM) applications. The lack of licensing requirements has greatly encouraged the growth of the wireless industry. These bands are used for consumer and commercial WiFi and WLAN applications as well as for commercial Radio Frequency Identification (RFID) and Supervisory Control and Data Acquisition (SCADA) applications. Here are some highlights of each ISM band frequency for you to consider:


900 MHz

900 MHz 9 dBi Yagi Antenna

The 900 MHz ISM band is known to be very narrow, thus limiting the maximum data rates. Typically applications such as SCADA and RFID use the 900 MHz ISM band since their data rate requirements are lower than applications found in the 2.4-5 GHz frequency bands. Many times the type of data packets being sent in these types of applications is a simple on /off command to something like a motor or value.

 

When obstructions such as trees and leaves are in the Line of Sight (LOS), the 900 MHz frequency will fare better than 2.4 GHz. The 2.4 GHz frequency is absorbed by water found in trees and leaves, which then causes path loss of the 2.4 GHz transmission. 900 MHz is often used in Non-Line-Of-Sight (NLOS) applications.

 

 

2.4 GHz

WiFi Grid Antenna

For the home user and commercial businesses, 2.4 GHz ISM Band is the primary band used for WiFi, Bluetooth, cordless phone, printer, keyboard, mouse and gaming controller applications. Voice, video and data communications are also typically used in 2.4 GHz systems where higher data rates are required (up to 300 Mbps for 802.11n applications).

 

2.4 GHz is the most widely used frequency (especially since it includes devices like microwave ovens, baby monitors, cordless phones etc.) and in some cases may even be overcrowded. When too much overcrowding occurs, your WiFi network signal may be weak or not work at all. In some cases it's best to use 5 GHz backhaul links to connect 2.4 GHz WiFi networks as 5 GHz is a less crowded frequency.

 

 

5 GHz

5.8 GHz Sectorized Antenna Array with four 90°  Sectorial Antennas

The 5 GHz frequency is often used in commercial WiFi applications. As mentioned above, it is often used as a backhaul link connecting two 2.4 GHz systems over some distance. 5 GHz is also the frequency used for the emerging standard 802.11ac which will provide up to 1.3 Gbps of wireless data throughput. Additionally, 802.11n can also use the 5 GHz frequency.

 

 

 

 

For more information about US Frequency Allocations, click here.

 

Wireless Tech Tips You Can't Live Without

January 23, 2014 at 8:36 AM

 

Here at the Engineering Hub, we strive to bring you topical and useful free technical support reference materials. For over 30 years L-com has built an extensive knowledge base of wireless tips and other valuable information to help you successfully design and implement wireless networks.

 

 Yagi antenna mounted

 

We have recently added several new wireless tech tips to our website. Many are based on questions we get from our customers. Here are a few:

 

 

Make sure to bookmark L-com's Technical Resources page as we are adding new content frequently. Some of our top downloaded wireless technical resource documents and tips are:

 

 

Typical LAN Structured Cabling: The Basics

January 16, 2014 at 10:00 AM

Keeping it neat
 

Typical LAN Structured Cabling Setup

We know things can get messy in your commercial building when installing any sort of cabling system. Many cabling systems require a full wiring closet or server room including racks, panels, patch cords, lightning protectors, routers, switches, and media converters. All of which is supported by a staff of IT professionals. 

 

Phew. That’s a lot to manage. And having Internet access in a commercial building is no longer just an option. It is a must.

 

Even if you are doing most of your file sharing and other network activities in the cloud, you can't get by without the basic cabling linking your office to an ISP. 

 

So what’s the solution? A Structured Cabling System, which is the cabling, connectors and accessories that make up the Local Area Network (LAN) inside a building.  At a minimum, this consists of a modem, router/network switch and Ethernet cabling. 

 

 

Here's the trick


Often you need something more complex than just a computer connected to the Internet.  That means you'll need an Ethernet router to handle internal network addressing, securing resources and providing a connection to the Wide Area Network (WAN).  You will also most likely require Ethernet switches to distribute traffic to many computers and servers in your LAN. 
 

Typical Ethernet Cable with RJ45 ConnectorSince routers and switches can't work alone, you will require Ethernet cabling- possibly a lot of it.  And when you have a lot of cabling, things can get even messier. Try out these high-quality right-angle Ethernet patch cables along with cable management rack panels to keep your area neat and organized. 

 

With all the different cables going to different systems, its obvious things can get confusing. We suggest color coding your network too. Check out our wide range of colors for Ethernet cables, here. If you specify that a certain color cable carries a certain signal type (such as phone or network traffic), you ensure that everyone who works on your network wiring can visually identify critical connections before they are disconnected.

 

As your network grows, you also need your structured cabling system to be scalable.  One good way to do this is to employ a well organized rack layout and utilize good cable management practices. This will make future growth easier to manage within your server room. Plan for future expansion by also including blank filler panels between patching sections in a rack and between network switching/routing equipment.

 

Around the building, set up plenty of user access points by terminating a minimum of two network ports per office workspace.  Installing keystone jacks in aesthetically pleasing wall plates or surface mount boxes will give an office space a finished look.
 

Typical Enclosure Setup with power, lightning protection, and networking productsFor remote and secure locations, use enclosures to house both wired and wireless equipment. To power these products, install Power over Ethernet (PoE) injectors and splitters that will eliminate the need for complicated electrical re-wiring. If the location is too far for traditional Ethernet wiring (about 100 meters and further), consider setting up a fiber optic link using commercial or industrial grade media converters
 

Finally, never forget the importance of lightning protection.  Electrical surges can occur anywhere with devastating effects on expensive and critical equipment. Nearly anything that carries an electrical current is vulnerable. 

 

Need more tips? Click here for our Telecom/Modular (Premise Wiring) tutorial page. 

 

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