The Opportunities and Challenges of LTE Unlicensed in 5 GHz
David Witkowski, Executive Director, Wireless Communications Initiative
In 1998, the Federal Communications Commission established the Unlicensed National Information Infrastructure or U-NII 5 GHz bands. These are used primarily for Wi-Fi networks in homes, offices, hotels, airports, and other public spaces and also consumer devices. U-NII is also used by wireless Internet Service Providers, linking public safety radio sites, and for monitoring and critical infrastructure such as gas/oil pipelines.

MMD March 2014

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Band Reject Filter Series
Higher frequency band reject (notch) filters are designed to operate over the frequency range of .01 to 28 GHz. These filters are characterized by having the reverse properties of band pass filters and are offered in multiple topologies. Available in compact sizes.
RLC Electronics

SP6T RF Switch
JSW6-33DR+ is a medium power reflective SP6T RF switch, with reflective short on output ports in the off condition. Made using Silicon-on-Insulator process, it has very high IP3, a built-in CMOS driver and negative voltage generator.

Group Delay Equalized Bandpass Filter
Part number 2903 is a group delayed equalized elliptic type bandpass filter that has a typical 1 dB bandwidth of 94 MHz and a typical 60 dB bandwidth of 171 MHz. Insertion loss is <2 dB and group delay variation from 110 to 170 MHz is <3nsec.
KR Electronics

Absorptive Low Pass Filter
Model AF9350 is a UHF, low pass filter that covers the 10 to 500 MHz band and has an average power rating of 400W CW. It incurs a rejection of 45 dB minimum at the 750 to 3000 MHz band, and power rating of 25W CW from 501 to 5000 MHz.

LTE Band 14 Ceramic Duplexer
This high performance LTE ceramic duplexer was designed and built for use in public safety communication and commercial cellular applications. It operates in Band 14 and offers low insertion loss and high isolation to enable clear communications in the LTE network.
Networks International

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October 2012

Designing Power Amplifiers to Operate and Coexist in the Public Safety Domain
By Dimitrios B. Kontolios, Sales & Applications Engineer, AccelComm/AC Group, Inc.

A prominent provider of wireless solutions approached us for assistance in developing power amplifiers for their systems because their engineers believed their current systems would not meet FCC Narrowbanding requirements for the next year. They supplied us with their specifications, mostly around the VHF/UHF, 700MHz, & 800 MHz Public Safety Bands anywhere from 5 MHz to 20 MHz bandwidths with 6 KHz and 12.5 KHz modulation spacing in their digital transmission capabilities. Although “the customer is always right” motto prevails in our business model, our diligent and always curious Product Line Manager decided to research and find out for himself if these specified power amplifiers that he was about to design would meet FCC requirements.

The FCC has implemented the Narrowbanding Mandate which states that all public safety and industrial/business land mobile radio systems operating in the 150-174 MHz and 421-470 MHz bands must cease using 25 kHz efficiency technology and begin using 12.5 kHz efficiency technology. The purpose of Narrowbanding is to operate more efficiently creating additional channel capacity, either with narrower channel bandwidths or an increased number of voice paths or a higher data rate per channel to support more users. The deadline for conforming to the Narrowbanding Mandate is January 1, 2013.

The 700 MHz Public Safety Band comprises 24 megahertz of spectrum designated for public safety use. The Narrowband segment of 769-775/799-805 MHz consists of 1920 6.25 KHz-wide channels operating as 960 pairs. 800 MHz Band Reconfiguration was implemented to address the growing problem of harmful interference caused by high-density commercial wireless systems to 800 MHz public safety communication systems at 806-824 MHz paired with spectrum at 851-869 MHz. All FCC requirements and further information can be found at:

To meet requirements, power amplifiers have to be very linear at all these very narrowbands to perform with efficiency. AccelComm is already prepared to meet these new stringent FCC requirements for its customers by providing power amplifiers with RF Predistortion techniques which are capable of compensating for nonlinearities such as AM-AM and AM-PM distortions, spectral regrowth, memory effects and other signal impairments. For more information on all AccelComm products and capabilities, visit:

AccelComm/AC Group, Inc.
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Uncertain Times for DefenseOpen’s Systems and Changes in DoD Procurement: This Time It’s Real
By Barry Manz

The U.S. Department of Defense has a well-earned reputation for inertia. Many proposals for change are made – but nothing happens. The COTS initiative, which promised cost savings through the use of off-the-shelf commercial parts, sounded terrific at the time. It heralded a major departure from standard DoD procurement that more or less guaranteed that every system would be different in part because it used parts that were developed from scratch, leading to “one-off” systems that were very expensive. Read More...

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