Articles by Alfred T. Yerger II
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Remote Monitoring And Measurement In Communications Systems
11/13/2013
In early October 2013, I was part of a panel discussion on test and measurement trends at the Tessco product show in Baltimore. One thing all the manufacturers there agreed on was the need for more remote monitoring and measurement.
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A Receiver Intermodulation Primer
5/29/2013
Here at Bird Site Optimization Services, searching for and resolving intermodulation problems is something we do on a regular basis. There is certainly enough of it out there to keep us, and probably a bunch of others, busy for a long time.
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Measuring Site Noise
11/16/2012
When working with customers on their RF interference problems here at the Bird Technologies Site Optimization Services group, at some point in the process we usually have to quantify the amount of environmental RF noise present at the site.
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It’s Duct Hunting Season
6/27/2012
We have a little saying around here at the Bird Technologies Site Optimization Services Group — “interference is a growth industry.” This is never truer than in the spring and summer. While atmospheric ducting can occur during any season, and often does, the warmer weather increases the frequency of these events, particularly for those near the coast.
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The Pitfalls Of Multiband Distributed Antenna Systems
2/22/2012
With the continued growth in the demand for in-building communications systems along with the high cost of installing a distributed antenna system (DAS), we are seeing more people installing systems designed to support multiple bands. Much of this is driven by the need to accommodate various services and agencies that have systems on different bands.
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Isolators — Radio’s Good Cop, Bad Cop
10/5/2011
Most of the columns you read here on RF Globalnet deal with the latest breakthroughs in the RF world. However, in this quarter’s “Bird’s Eye View,” I would like to take a closer look at something old, the ferrite isolator. First, the correct name for the device is a circulator. Isolator is the name of one of the more common applications, especially in the land mobile radio (LMR) industry.
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Guest Column: Signal Boosters Are Not Plug And Play
7/8/2011
This article is part of a series of quarterly guest columns by Alfred T. Yerger II, RF Engineering Specialist, Bird Technologies. In this installment, Yerger describes how signal boosters, also called bi-directional amplifiers, or BDAs, are becoming very popular as public safety agencies, among others, move to provide seamless in-building communications. Many places now have ordinances requiring building owners to provide facilities for in-building communications.
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Guest Column: Do Water Towers Make Bad Antenna Sites?
4/6/2011
I'm often presented with the question, "Do water tanks make bad antenna sites?" The answer I give is what my wife calls the consultant catch-all answer — it depends. There are a number of factors that determine whether a water tower system will be effective or not, including the type of water tower or tank, the frequency band of the system, the presence of other systems, the need for omnidirectional coverage, and the intermodulation situation.
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Guest Column: Antenna Location Is Not An Architectural Decision
1/5/2011
This article is part of a series of quarterly guest columns by Alfred T. Yerger II, RF Engineering Specialist, Bird Technologies. In this installment, Yerger describes how antenna system design and placement is critical to proper system performance. Whether the issue is intermodulation, receiver desensitization, transmitter noise, or adjacent channel interference, the real source of an antenna interference problem is often antenna location.