Radio World - November 19, 2008 - (Page 45)

November 19, 2008 OPINION radioworld.com | Radio World GUEST COMMENTARY Radio Thrives in Digital Age Both Legacy FM Radio and Emerging Services Demand an Increasingly Broad Palette of RF Solutions by Mick Bennett Three key factors underpin the long history and bright future of radio broadcasting: a robust business model, relatively simple technology and overall cost-effectiveness. Over the past century, broadcast radio has evolved into the most ubiquitous medium of the broadcast world. Heard in almost every household, street corner and village around the world, broadcast radio continues to be a vital and fast-growing sector. resultant receiver interference risks with sharper filtering options. Where two-pole filters may have once sufficed, more sophisticated three- and fourpole filters are fast becoming the FM norm. cally required in L band deployments — and the availability of receivers. Arguably one of the most pressing technical challenges with DAB/DAB+ is addressing issues of RF filtering, power handling and voltage peaks. The power of a DAB/DAB+ service can be as high as 10 kW — of the same scale as a DTV service — yet it is squeezed into a narrow 1.5 MHz channel. This exacerbates the digital service peak-voltage challenge, and also presents filtering and power-handling challenges. Filter response To meet these challenges, companies such as Radio Frequency Systems (RFS) are exploring solutions such as double cross-coupled filters, filters with not one but two cross-couplings. These achieve much sharper filter Core objective Even pitted against a growing field of highly competitive alternative media, the “bullet-proof” broadcast Similarly, the rollout of new radio business model has analysts preFM services demands more dicting that legacy analog radio has a space on increasingly congestlong future. ed broadcast towers. This Nevertheless, it is widely underdemands a broader range of Mick Bennett stood that emerging digital radio variFM broadcast antennas, feaants will sustain and shape the future of radio over the turing innovative radiation patterns, bandwidths, mountnext decade. ing options and physical compactness. Around the world, the commercial radio broadcasting This diversity of need is the defining aspect of 21st market is renowned for its fiercely competitive nature century FM radio broadcast systems, which vary widely and the core objective of broadcasters to establish and from site to site and from broadcaster to broadcaster. retain market share. FM radio — the most refined analog offering — Technical challenges tends to be regionally localized, leaving openings for The transition to digital radio is now well established more radio broadcasters to join the market. in many parts of the world, most notably in the United As a result, the industry is experiencing dual pressures Kingdom, the United States, Denmark, Norway and — one from new broadcasters wanting to join the mar- Switzerland. ket, the other from incumbent broadcasters looking to The reasons for the push to digital radio are similar to expand their services and thus hold on to market share. those behind the digital television transition — spectral Both require spectrum and broadcast infrastructure in and commercial efficiency; enhanced services to coman increasingly congested climate. plement traditional audio, such as text, images and listener interactivity; and improved quality. Spectral squeeze In many respects, the choice of digital radio platforms This “spectrum squeeze” in the FM radio world has comes down to national and regional availability of inspired a wide range of innovative RF broadcast solu- spectrum, specifically that in the VHF band III, L or S tions. bands. Traditionally, FM is broadcast in part of the VHF In the case of the more popular DAB/DAB+ platband II as 200 kHz channels with 800 kHz spacing. form, the major challenges include spectrum availabiliSpectral squeeze is now behind a rising trend to ty; addressing deployment models — conventional shrink this channel spacing to 600 kHz and address any “broadcast” models vs. the “cell-style” topologies typiwished to purchase one of my software programs, one that designs antenna matching networks. I asked him some questions which anyone experienced in the design and adjustments of Tee networks would answer in a second. He could not. Heard in almost every household, street corner and village around the world, broadcast radio continues to be a vital and fast-growing sector. response in a fraction of the footprint of a conventional filter, along with a reduction in in-band insertion loss. Also promising are technologies such as advanced water-cooled filters, in development at RFS. The first of their kind in the world, these filters specifically address the uniquely high power-to-channel bandwidth ratio of digital radio. Digital radio antenna systems are also evolving and include a range of L band panels and VHF band III antenna solutions that help legacy FM and emerging digital services coexist on a single broadcast system. In the future, challenges will stem from the evolving global “transmission mask” specifications for digital radio, most specifically, their interpretation and translation into practical network effective radiated power (ERP) levels and filtering solutions. Though different generations, legacy FM radio and emerging digital radio services have much in common. Both will support the powerful and growing radio business model for some time to come. For their survival and growth, both demand an increasingly broad palette of RF solutions, a rich mix of antennas, filters, combiners, feeders, patch panels and so on. Flexibility and scalability, along with a complete endto-end understanding of the radio broadcast system as a whole, are and will continue to be essential. Mick Bennett is global product manager, Broadcast and Defense Systems for Radio Frequency Systems (RFS). I saw a documentary on the design process for the Boeing 777 jetliner. Boeing asked crewmembers for input. One captain was astonished at this. “You are asking me?” was his response. I recall Harris saying that field service had a lot of input on the design of a new series of FM transmitters because engineering was tired of hearing their complaints of inaccessible components, adjustments, etc. A wise move. Back in my younger days when I thought life was all about cold beer and crazy women, I worked in manufacturing. It was an excellent education in the process of design, prototyping, testing and manufacturing a product. I believe I speak with some expertise on this subject. Cessna will sell you an airplane and ensure it operates within specifications. They will not, however, give you flying lessons. Tom Osenkowsky Brookfield, Ct. The author is a radio engineering consultant and contributor to RW. Opinions are his own. Designers Continued from page 44 Manufacturers prefer not to hire tech writers as it adds cost to the products. Second, designers are under pressure to get out the next product. With the pace of evolving technology there is fierce competition in the marketplace. It takes longer to construct and test a prototype, then mass manufacture it, than it does to design it. Designers are not afforded the opportunity to prepare detailed documentation. That was yesterday’s product, let’s work on the future, not the past mentality. Third, consider the audience. What is the experience, competence and ability to the end user? Experienced engineers are becoming scarce. It is cheaper to have users call tech support than it is to use up the more valuable time of designers to write a manual that few will understand anyway mentality. To the last point: Some years ago I was contacted by an engineer who fied to use the tool (software). One of the key elements in all my programs is user-friendly. A well designed product should be intuitive to the qualified end user. Let’s look at some consumer devices. Some VCRs are nearly impossible to pro- Designers are not afforded the opportunity to prepare detailed documentation. That was yesterday’s product. — Tom Osenkowsky I elected not to sell him the program because I foresaw myself with endless “support” calls and having to do the design myself. He refused my offer to design the network if he provided me measured data. He was basically unquali- gram without having to read manuals and decipher what was going on inside the designer’s head. Many designers are not users. Therein is a major problem. They design but do not have to maintain their creations. http://www.radioworld.com

Table of Contents Feed for the Digital Edition of Radio World - November 19, 2008

Radio World - November 19, 2008 IBOC+Satellite? Subscribers Not Impressed The New World of AM DA MoM Contents Newswatch Buterbaugh Legendary in Upper Midwest From the Editor Buterbaugh: His Colleagues Look Back Workbench: What’s Wrong With This Picture? KFI Back at Full Power With New Tower 3G or Not 3G? That Is the Question Exploring HD Radio Availability in Philadelphia HD Radio Scoreboard Digital News GEP For That Bird Without a Wire A Chat With Bay Country Radiolicious Brings Radio to iPhones People News Belar FMHD-1 Clears the Skies Reader’s Forum Radio Thrives in Digital Age A Vote for Change

Radio World - November 19, 2008

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