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First-Person Commentary: Evolution of Digital Medium and Long-Wave Transmitter Product Line at Harris Broadcast

This paper discusses how a major solid-state (SS) program got started in a high technology company and became a major factor in the worldwide (WW) market place in a few short years.

The author is retired from Harris Broadcast. The paper was written in the 1990s and includes updated information at the conclusion.

This paper discusses how a major solid-state (SS) program got started in a high technology company and became a major factor in the worldwide (WW) market place in a few short years. It shows how a good idea does prevail but it must be coupled with a knowledge of the market and the technical background to bring the idea to fruition and clearly must be adapted to the available market place in this case WW. The new product is DX Radio Transmitters.

The writer, as an engineer starting in 1950 and later manager of very high tech electronic companies, spent his working lifetime in high power Radio Frequency Systems. One of the major projects, its evaluation, overcoming skeptics WW, developing a team to execute the program and finally seeing the product developed be a major factor the WW Medium Wave (MW) and Long Wave (LW) market place and moving the company, Harris Broadcast, to be a major factor in the market place WW, moving from a 10% factor to approximately 35% in a few years (market share).

The project really got moving in 1988 after a non competitive low power start in 1987. The basic concept was developed by Hilmer Swanson, a senior engineer at Harris Broadcast, and a 10 kilowatt (KW) model was demonstrated at the NAB Show in 1987.

The writer recognized in 1988 that Swanson’s concepts could be cost reduced while holding the design integrity and move it from 10 kW to very high power of 100 kW to beyond 500 kW and finally 2000 kW. Because of the long involvement with high power transmission and being involved for about 38 years at the time WW, it was quickly realized that about 80% of the installed power was above 50 kW and that all the key players at the time had capabilities up to megawatts using primarily vacuum tubes in the final stages and series SS modulators.

It was noted that many countries had very high power transmitters, in addition to the 10-50 kW units, to communicate with their people (many units >1000 kW). Because the leader had to be dominant at high power (>50 kW) to be a major factor in the International Market for MW and LW at the time, concepts were developed to move the DX-SS concept to 100 kW, then 200 kW, then on to 500/600 kW and finally to 2000 kW, knowing also that this would lead the way for the 10 to 50 kW market WW and also be prepared for the US Market which has a maximum power rating of 50 kW. Thus we had the background to introduce a far superior product at competitive prices to the WW Market. Included is a discussion how a very dynamic team was developed to execute the project. Also noted was the fact that the FM band was becoming over crowded in many countries like Italy.

The paper describes how the concept got started, its evaluation and major success in the WW Market. One of the major successes was to overcome the Skeptics within Harris and other WW suppliers and users as we gradually replaced older vacuum tubes transmitters with a far superior Solid State Unit and move the market for all suppliers to be essentially 100% SS by 1995. It must be noted that the other designs did exist prior to DX but were limited in production to about 50 kW at the time.

This is an easy story to tell by the writer as the program success is also included with data up to 2004 starting in 1998. The major part of the paper takes place in 1988 to 1996 time frame, however. In this time, the writer was working well into retirement to help to continue the success of the DX program. It demonstrates how a company can move from a minor contributor in the WW Market to being a major factor with a good idea and it’s proper execution with very dedicated and knowledgeable people within the framework of the supporting company.

The amount of installed LW and MW power from 1988 to 2004 exceeded 200 MW (megawatts) with the DX share of approximately 35% for both tube and SS types and approximately 50% of the SS portion alone. The division between low [up to 50kw] and high [above 50kw] power is about 40% and 60% respectively at the present time.


The concept of high power DX developed to a major extent because I spent my complete career working on high power systems starting with a pulse modulated gridded tube operating at 5000 kW peak, 300 kW average and at 400-450 mega hertz at RCA Lancaster. My experience with Radio Frequency Power continued to develop over the next 45 years. This also included the development of megawatt tubes and circuits at RCA and EIMAC for the AM market and working with a transmitter developer and founder of Continental Electronics, J. O. Weldon, to finalize a 2000 kW MW system using 1000 kW vacuum tubes. J. O. Weldon was clearly a leader WW for high power medium wave transmission starting after WWII. High power became a love! At the same time I had the opportunity to meet most of the key high power users and developers worldwide (WW).

During that period, I also kept track of the world high power users including VOA, RFE, various MOI’s, Accelerators, National Labs, etc.: all users of high power systems worldwide. Most of this information of users was placed in Lou Ann Duryea’s marketing files somewhere within Harris. So the world market and locations of all high power users were catalogued in the back of my mind throughout my career. Thus, by coupling this background of high power interest and experience with the fact that RCA sent a large group of engineers, myself included, to Princeton for about one year to be educated in solid state technology, the stage was set for interesting work in solid state VLF, LF and MW. Little did I know at the time that I would work with Hilmer Swanson, the outstanding engineer, who conceived the DX approach to digital radio systems, and with Harris Broadcast on the DX program which yielded the DX-1000 and the DX-2000 and all transmitter powers down to 10 kW, now installed World Wide (WW).

Keeping track of the worldwide users for over 30 years and recognizing that the market was abandoned by the major suppliers during the 1980s as far as total SS technology was concerned, led to the long range plans to push the DX concept to very high power (10 kW to 2000 kW). Knowing that the FM channels WW were becoming congested and that the MW channels were more open, coupled with the fact that many of the existing MW systems were 20-30 years old and consisted of inefficient technology also helped us to project the potential for the DX when the initial plans were laid out. And at the same time, noting that the world was changing with the emerging countries wanting to modernize their own communication systems helped to create the positive forecasts made. At this time the World Wide MW-LW installed base was >1000 MW of power with the major portion by far above 50 kW, the limit for the USA, ie. In Algiers, 3-2000 kW MW units are used to cover the country. Many other countries use MW High Power to broadcast to the population. This is why the major replacement and new markets is for MW to LW power above 50 kW. It must be noted again that installed power dominates above 50 kW and numbers of units dominate below 50 kW in this important International Market. These emerging countries usually started with MW, then FM, then TV and lastly SW to communicate with the people in and outside their respective countries. Medium wave (MW) was first because of the simplicity of the systems and the very low cost of the receivers (~$5) plus its excellent large area coverage. This background coupled with the published information on the North American market led to the very optimistic forecast and product program proposed when the DX-10, DX-50, DX-100 and beyond were introduced. Building for future sales was high risk but it certainly paid off for the Division. Also having some experience at 500 kW using solid state devices at low frequencies helped to formulate the project capability of DX. The vision for DX-2000 was formulated! Step by step, evolution from 10 kW to 2000 kW was developed. It became obvious that having a reputation in high power set the stage for MW worldwide.

Then the dream to become the world leader in MW was formulated: a real challenge because Harris Broadcast was not recognized as a high power or dominant MW supplier in the international market at that time where my data showed that greater than 70% of the Market existed.


In 1987, Harris introduced the DX approach at 10 kW but felt that the market was not there (10 kW solid state). In the 1988-1989 timeframe, we accelerated the 50 and 100 kW DX concepts while cost-reducing the DX-10, and built a larger number for risk stock and sold them all immediately and thus the DX solid state product line was launched for Harris Broadcast.

The concept of Power Block was developed to increase the projected power to 1000 kW and beyond. The concept employed N-Way combiners exactly the same way developed for TV and FM at the time, where the basic module was ˜ 1000 W. Lumped constants (coils and capacitors) were substituted for transmission line sections to combine the basic power blocks (100 to 200 kW+) up to 2000 kW.

I quickly realized that the Power Block concept would yield powers up to 1000 kW and beyond for a very special market (for Harris). This market required a higher level of engineering for each system but the great potential for good margins existed when competing against single tube high power transmitters in the international market.

At that point, it was easy for competitors to say that an approach consisting of SS modulators and a single tube was the only cost effective way to go to 500 kW and beyond. But we persisted toward developing DX up to 2000 kW and at the same time developed concepts which moved the power block rating from 100 to 200 kW and higher, and drove down the $/W for SS MW, thus becoming very competitive to the single tube approach (but having all the SS advantages). We now offer power blocks in the 100 kW to 200 kW (and higher) range, depending on our customers’ desires for positive modulation. A simple 2-way combiner with 2 DX-1000’s yields a DXD-2000. An N-way (5-way) combiner used with 5x 200 kw Power Blocks yields a DX-1000: a very reliable and cost-effective transmitter.

At the same time, the measured reliability for the power block was improved to 100,000 hours and above but the tube people continued to talk about much lower numbers. These facts coupled with knowing the WW market (as indicated previously) and adapting to it since 1988-1989 were major keys to our successes.

The major emphasis on high power developed when we told the world market through personal letters that Harris was building a 300 kW SS AM transmitter and we invited the key people in the world to evaluate it. This was a very successful program. The same approach was done previously at 100 kW and later for 200 kW, the aforementioned 300 kW, the 400 kW, then the 600 kW and on to 2000kw. Many doubters inside and outside of Harris continued to exist but the team moved forward and prevailed. After the DX-600 success, the DX-1000 transmitter was sold to the VOA.

When we announced to the world that we were offering a DX-300 for test and evaluation at the Quincy plant in 1990, we had many doubters WW, including the original buyer from Slovenija for the transmitter. When we committed to a 12-hour heat run at greater than 120% positive tone modulation (not 10 minutes out of each hour, but fulltime), the customer bought the transmitter after a very successful test. This was the major start of moving transmitters WW, including DX-2000s at 110% tone modulation 100% of the time. The DX-600 was introduced in 1991 and the DX-2000 in 1995. (The DX-2000 is capable of 2000 kW of carrier power.) This conservative design approach by the team led to the measured MTTF (Mean-Time-To-Failure) being many times higher than any competitive tube design for MW.

At the same time period, James Wood, engineer and technical author, located in England, visited Quincy to interview us and to see firsthand the DX concepts being evaluated in detail, and this led to an honorable mention in his famous “History of International Broadcasting” book issued about the year 2000. James Wood, like the writer, spent many decades as engineers in the High Power WW industry and grew up with High Power vacuum tube systems. He was a major skeptic initially about my enthusiasm and projections for High Power SS MW & LW systems plus actual results.

Refining the market details, knowing the customers and feeling that high power MW and LW would move with the right product, continued to fuel this extremely high risk program ahead, generation after generation. Needless to say, this led the way in the international market at all power levels for Solid State Radio Transmitters.

Recent orders (˜1995) for 15 DX-600s, 2 DX-1000s and numerous 10-50 kW units, a letter of intent for 2 DX-2000s, justify the dream and the high risk taken to get into the marketplace. Needless to say, the large number of 10, 50, 100 kW, 200 kW and 300 kW transmitters sold previously laid the foundation for the present success. Well over 1000 (statistic from 2001) DX transmitters are operating worldwide since 1987. Harris Broadcast is now well-founded in the world MW and LW market at all power levels.

The bright future continues to look as forecasted for MW and the high power MW is a key part of the plan. Harris Broadcast is now at least two years ahead of the industry because of their foresight and the high risks taken many years ago to enter this new market (˜1996).

The future remains bright for DX products at all power levels up to 2000 kW. Many opportunities exist at 2000 kW today based on the DX leadership. Forty-five years of high power experience are paying off. Being a major promoter and contributor to the high power DX program at Harris, including the early planning (which remains valid today) and being part of the sale of major orders worldwide is a comforting factor for this part of my career. About 200 aging 200 to 2000 kW transmitters worldwide need to have the advantages of a DX replacement! Now! This is in addition to the numerous 10-100 kW units WW.

It goes without thinking too much that the team at Harris rallied behind the high power program emphasis in a big way. Even the doubters became believers as the success continued. Many thanks go to the factory and Pat Humke along with Harvey Baker, both production managers, Jeff Malec, a DX engineer, Bill Little, a systems engineer for DX, and especially Hilmer Swanson from the engineering group, plus the complete sales department. Guy Numan and Joe Huie, both corporate managers, were big supporters and promoters of the program. Martha Rapp and her team were great in the development of publications, promotions and ads.

Special thanks go to George Koumblis, the Middle East sales engineer who undoubtedly gave much to the first DX-2000 program. We had input from our competitors also which helped us to recover the apparent loss of the Qatar program with George at the forefront. Special thanks also go to the engineering technicians who worked in Building 3. Those include Steve Cane and Steve Meleney. Their efforts to collect data for our customers were a big help.

The Qatar program is a clear example of how our high power customers want to be sold on their system requirements. The customer wants to be involved with the Sales Department taking the tenacious lead, leaving the Engineering Department, Systems, Finance and many other aspects of the supplier to provide a supporting background. Management people must also be involved in the support of the proposal. It is critical to have the Management know the engineering and marketing details of the program overall. The customer is making a huge investment and wants to be certain that the supplier (Harris Broadcast) has the capacity and interest to meet their desired requirements. My experience over the years with high power systems also supports this approach to sales and I feel this approach must be followed when the customer is spending large sums of money on his system like the 2 megawatt at Al Arish, Qatar and Vietnam. It is well-known that to be leaders in MW/LW worldwide, the supplier must have unique capabilities up to 2000 kW.

John DeLay, Radio product line director during this period, has grown, and become recognized in the business because of his high power experience and will continue to lead the charge in the future. His contribution must clearly be recognized.

Program management’s enthusiastic and capable support after and during the sale has helped to develop a cadre of customers dedicated to Harris Broadcast. Through Jim Brown’s, a program manager’s, efforts, along with the rest of the team, Harris now enjoys a reputation at VOA/RFE as being a capable, cooperative and reliable supplier. Key VOA/RFE people have stated several times that Harris Broadcast has the very latest technology and has a group of people who really know what the customer needs. Also, having the best factory and organization in the world were major assets in the program. One of the most faithful and largest DX customer was RAI Italy made a major contribution to the Quincy team by meticulous review and enforcing the details of supplied manufacturing documentation. This attention helped to refine the documentation process for manufacturing and was partially responsible for the extraordinary measured reliability WW. China, Spain, VOA, Italy and Romania were major DX customers and have in total multimegawatts of installed power and have experienced the features discussed; all having a major influence on the overall DX success in manufacturing. Customer feedback and involvement at all levels including Program Management are an important part of successful programs like DX. Also a major Quality Program executed under the direction of Sue Osier was a large factor in the measured reliability WW.

I would be remiss if I did not include Debi Gehring, executive secretary, because she somehow deciphered my writing to draft various bulletins, worldwide letters and other documents for the high power program (including this one).

Needless to say, the Harris team must be very proud of the DX program as MW was the major contributor to the Division’s financial success for the 8 years following its start in 1988. Good team planning and execution of the plans by the team each year, helped to keep the momentum moving. DX continues to be a major contributor to the Division’s success (2004) even though the competitors are gaining market share.

So, in conclusion, many people in the Division were part of this program and space does not permit all names to be recognized; I only recognized some of the major contributors to the DX high power success, an easy story to tell seen through one pair of eyes. A dream did come true through a truly dedicated and capable group of people at Harris Broadcast! We are being recognized worldwide as the world’s MW technology leader and are fast becoming recognized as a leader from the MW and LW systems viewpoint!

(The aforementioned information was primarily the background up to 1995-1996)

Addendum I – Status 1996

The fact that the DX-1000 recently won the technology award at IBC over an excellent shortwave development by a competitor makes the Harris team extremely proud of this major milestone. Harris Broadcast expects to continue to make major milestones in the future for DX, one being the successful operation of a DX-2000 (2000 kW) in Qatar and Vietnam.

Harris Broadcast will continue to lead the world market for medium wave transmitters and systems in the future as further developments continue to meet the requirements of the MW, LW and VLF markets as it converts to solid state (DX). The DX program understands that competitors will develop, so the DX concept must be continually improved to remain competitive in the world market for medium and long wave transmitters. The program goals have been met and continue to grow and must continue to meet the new digital systems being developed.

Addendum II – Status 2001

The total number of installed units now exceeds 1100 and total installed power exceeds 48 megawatts. At power levels at and above 100 kW, Harris has at least two and a half times the installed power (SS) worldwide of its nearest competitor. Also MTTF (Mean-Time-To-Failure) is at least 10 times tube transmitters.

Addendum III – Status end of 2004

The total number of installed units of DX type now exceeds 1500 at a total power level exceeding 70 MW representing about 35% of the total MW power installed since 1988 when the Harris share WW was about 10%. The total MW power sold from 1988 to 2004 includes about 60 MW of tube type systems bringing the overall total to greater than 200 megawatts. Many of the tube transmitters used SS modulators and this fact gives the nearest competitors about 35% of the power installed during that time period also. The worldwide market has been approximately 100% SS since 1995 for MW and LW transmitters. The 35% share for Harris would be about 50% for the SS (Solid State) portion alone.These percentages would be less than half if high power was eliminated.

Note 1:

The DX type systems WW are all ready (with few modifications needed) to handle the new DRM and IBOC type digital modulation approaches, including the new generation models up to 50 kW.

Note 2:

Approximately 80% of the MW and LW power installed WW is above 50 kW, the maximum for the USA. Needless to say, units dominate below 50 kW.

Note 3:

To be a dominant WW supplier for MW and LW, the supplier must be recognized for its products up to 2000 kW and beyond. VLF is also a potential market.

Note 4:

Examining the WW installed base, the future for LW (Long Wave) and MW (Medium Wave) transmitters continues to be look very bright. VLF must be considered also for DX.

Although not discussed herein, the cost advantage alone when one switches to DX type systems is measurable with the payback being approximately 5 years. And at the same time, the customer gets higher quality audio approaching FM, much better coverage due to high side band energy, very high efficiency (>83%), much greater reliability (>10 times the reliability of the old systems), and they are getting a system that is ready for the modern modulation systems such as IBOC amd DRM!

During the past few years, the competition has become stronger in the DX type marketplace and some have second and third generation solid state product which is cost-reduced and tends to meet the basic international specifications. The DX concept can continue to gain back market share as it has the measured MTTF higher than that experienced in this market while the new generation High Power is made available. Many 1000 kW and 600 kW units are now operated remotely because of this measured reliability.

End Summary:

The future remains bright for 2005 and beyond for the DX family of transmitters! Hilmer Swanson, the DX digital radio inventor, the writer, plus the complete radio team at Harris are very pleased to see the excellent success of this major Radio program WW since 1988. The writer is pleased to note this major success for MW transmitters WW and to show how the involvement in High Power paid off by expanding the concepts developed by Hilmer Swanson, leading to the success of this major product line which moved Harris Broadcast to a dominant position in the WW-MW-LW marketplace, moving from ˜10% to ˜35% share in a few years. Most of this penetration was initiated in the 1988 to 1996 time frame and essentially changed the industry from vacuum tubes to completely Solid State transmitters with the exception of VLF which may use output vacuum tubes for the near future.From 1995 forward ,almost all MW transmitters are solid state

Numerous 2000 kW transmitters and likewise 1000 kW SS transmitters are now operating along with hundreds in the 60-600 kW range in addition to >1500 units WW at 50 kW and lower.

From 1988 to 2004 approximately 140 megawatts of SS-MW & LW transmitters out of approximately 200 MW total are now installed; and have clearly demonstrated the extraordinary long life, high sideband power, FM like sound, reliability far beyond that of tubes in this type of application etc, resulting in the remote control of MW-LW transmitters from phone lines (an unheard of application with previous approaches), also, the conversion to SS offered a fast payback for investment, often 5 years or less, because of the high efficiency (>83% with typical being in the 85 to 88% range), very low repair costs, very low replacement costs and offered the extraordinary reliability, etc.

Again, a good idea with proper execution prevails! Also to have a team which loves their job and are willing to follow approaches which clearly led to extraordinary job satisfaction and rewards for them and their company are major keys to a program’s success. The “Crown Jewel” program for AM where a Family of Mediumwave [MW] Broadcast Transmitters that covered worldwide [WW] requirements was the DX for Harris Broadcast and continues today!