The Low Down on Low-Loss Coax Cables for Wireless Applications

August 17, 2017 at 8:00 AM

 

It may seem counterintuitive that a wireless network would need cables, but it’s true. The components of a wireless network, such as access points, amplifiers and antennas, all need cables to communicate with one another. Antenna cables introduces signal loss in the antenna system for both the transmitter and receiver. In order to reduce this signal loss, you need to either minimize the cable length, if you can, and use only low-loss or ultra-low-loss coax cable s in order to connect access points and amps to antennas.

 

Coaxial cable is one of the oldest signal cabling types and is still used today because it is robust and very good at carrying a signals over long distances. The term coaxial comes from the inner conductor and the outer shield sharing a geometric axis. The term "low-loss" refers to the cable's relative low-attenuation (loss) over distance. The general rule is that the thicker the cable is, the less loss of signal there will be over the length of the cable.

 

RG-style cables were the original standard for coaxial cable, but the signal in these cables degrades over longer distances. This isn’t an issue when covering short distances, but in a wireless application it is critical to maintain the signal strength throughout the cable and until it is sent out through the antenna. Thus, low-loss coaxial cable was created offering lower attenuation and better shielding, a much better solution for wireless systems than RG-style cables. Low-loss coaxial cables also use solid center conductors which provide lower attenuation than the stranded conductors found in some types of RG-style coax cables.

 

Low-loss coaxial cables are ideal for use in WLAN, Cellular, PCS, ISM and many other wireless communications applications. They are offered in multiple sizes with a three-digit “series” number designating the thickness of the cable and the low-loss properties. For example, 400-series low-loss coax is thicker and has less loss than 200-series, and 200-series is thicker and has less loss than 100-series. While the thicker cable will provide less loss, it will also be heavier and less flexible, though ultra-flex versions of the thicker series cables do offer more flexibility.

 

Here is a comparison chart for popular types of low-loss coaxial cables:

A Closer Look at PIM

January 14, 2016 at 8:00 AM

 

We’re not talking about a Personal Information Manager (PIM), or Product Information Management (PIM) or the delicious gin-based British beverage – that’s Pimm’s. The PIM we’re talking about is Passive Intermodulation, which may sound imposing, but here we’ll break it down for you.

 

What it is:

Passive Intermodulation (PIM) is a type of signal interference in a wireless system. PIM can be a problem in almost any wireless network but it can really wreak havoc on distributed antenna system (DAS) and LTE networks. DAS networks are used to distribute cellular and Wi-Fi signals throughout a building or area, and LTE networks support high-speed wireless access for mobile phones, tablets and other mobile wireless devices. With both of these technologies supporting many of our wireless devices, it has become increasingly important to detect and lessen PIM’s effects.

 

Why it happens:

PIM is caused by nonlinearities in the passive mechanical components of a wireless system such as antennas, cables and connectors, especially in places where two different metals come together. As nonlinearities increase, so do PIM signals. PIM in the transmission path degrades the quality of the wireless communication system. Damaged RF equipment or even nearby metal objects such as guy wires and anchors, roof flashing and pipes can also be sources of PIM.

 

Additionally, PIM can be caused by two or more carriers sharing the same downlink path in a wireless network. This practice is becoming more common as wireless networks become increasingly complex with multiple technologies and technology generations at a single site. When two signals combine, it causes signal interference and can significantly impact the performance of DAS and LTE networks.

 

How it's measured:

PIM is measured in decibels relative to the carrier (dBc) or decibel-milliwatts (dBm).  Levels near -100 dBm or less are generally considered good, but the lower the better.  Tests have shown that when PIM levels were increased from -125 dBm to -105 dBm there was an 18% drop in download speeds, even though 105 dBm can be considered an acceptable PIM level.


How to protect your network:

Individual components are often tested for PIM during the design and production processes to make sure that they aren’t significant PIM sources once they’re installed. In the case of a DAS, sometimes the entire system is tested for PIM as well as the individual components. Installation also plays a critical role because proper connections are necessary to keep PIM levels to a minimum.

 

PIM is also assessed during the cellular site placement process. Ideally, this happens before the cell site and antennas are positioned as well as during the installation process.

 

Plus, an increasing amount of test companies are offering specialized equipment to detect, pinpoint and address PIM sources. There are also low-PIM rated products now available to help keep PIM at bay. 

 

PIM-certified equipment is becoming more common. For example, antennas may be PIM-certified to a level of -140 dBm and those requirements are becoming increasingly strict.

With so many devices dependent on strong wireless signals, PIM could definitely throw a wrench in the system.  Fortunately, there are steps that can be taken to identify and prevent the adverse effects of PIM. 

 

The Wi-Fi Hotspot Boom

February 12, 2015 at 10:00 AM

 

Mobile wireless use has spurned a boom in the number of worldwide hotspots. Now as most of you probably know a hotspot is an area where Wi-Fi is provided as part of a “perk” typically found in businesses such as coffee shops, restaurants, sports stadiums and other public areas where people congregate.

 

In addition to the “perk” aspect of hotspots, most of world’s major voice and data carriers have also installed hotspots to help offload 3G/4G cellular Internet users to Wi-Fi networks which is more cost-effective for these mobile carriers/providers as well as mobile users like you.

 

According to ABI research hotspots will continue to grow at a CAGR of 15.0% between 2013 and 2018, to exceed 10.5 million hotspots worldwide. The Asia-Pac region has led this boom with over 68% of the worlds Wi-Fi hotspots! North America is fourth in the pack with over 8% of the worlds installed hotspots. These numbers include Wi-Fi hotspots deployed by mobile and fixed-line carriers as well as third party operators.

 

ABI also states that it is expected that global mobile data traffic will grow to 190,000 petabytes in 2018, up from 23,000 petabytes in 2013. Now that’s a lot of growth!

 

What this means to you is that you will most likely always find a Wi-Fi signal when you are out and about saving you cellular bandwidth (monthly plan $ savings) and sometimes even providing faster downloads and even better signal  strength in some areas.

 

We here at L-com are a part of this boom by providing both large carriers and small private hotspot owners with high quality antennas, RF amplifiers, low loss coax cable, access points and equipment enclosures to help facilitate this hotspot explosion.

 

Our wireless products support 2.4 GHz and 5 GHz Wi-Fi frequencies as well as cellular frequencies fit every hotspot application.

 

Tell us about your hotspot application in the comments area below.

 

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