"Broadcast Wind" Blog Spot

Robustness of Broadcast Systems to Multipath Interference from Wind Turbines

2012-01-25T10:12:00.000-05:00

Robustness of Broadcast Systems to Multipath Interference from Wind Turbines

by: Charles W. Rhodes

for: Broadcast Wind, LLC

Transmitted TV signals are waves of energy and act like waves in water and/or light waves. That is, they are reflected when they strike an object. They can also be diffracted (change direction) when they encounter an edge such a mountaintop or the blade of a wind turbine.

Basic Facts about TV Signal Propagation

TV signals are strongly reflected by metal surfaces whose dimensions are greater than a critical length of the reflecting surface. This corresponds to about 18 inches for signals in the UHF TV band (Most TV signals are in this band.) and to about 53 inches for FM radio signals. (FM radio reception can be affected by extremely strong echoes.) The steel tower and to a lesser extent, the non-metallic blades of a wind turbine will reflect TV signals. These waves move at the speed of light. That is about one sixth of a mile per microsecond (1 one millionth of a second) or six microseconds per mile. The effect of reflected signals is to create echoes of the TV signal which have traveled further than the distance from the transmitter to the receiver; hence they are delayed and generally weakened with respect to the direct signal from the transmitter. In some cases, the direct path from Transmit to Receive is blocked by man-made structures or hills. An illustration of how echoes can be caused by reflections from a wind farm is shown in Figure 1.

Figure 1: Wind Farm and Transmitter Site proximity Example (A-town)

The Effect of Echoes (Ghosts) on Analog TV Reception

Analog TV signals from the A-town Transmitter of Figure 1 would have suffered a lagging “ghost” (an echo), part way across the screen and to the right of the image formed by the direct path signal. The longer path reflected signal is much weaker than the direct signal at the viewer’s home. With analog TV signals, even a ghost image echo 10,000 times weaker than the direct signal was annoying to viewers. [1]

If the direct path were partially blocked by a mountain range or man-made structure, the delayed reflected signal arriving at the receiver may be stronger than the direct transmitted signal. In this case the weaker signal (the ghost) would lead the stronger signal.

The Effect of Echoes (Ghosts) on Digital TV Reception

The US upgraded from analog to digital (DTV) in 2009. Canada will do so soon. The effect of echoes on DTV reception is much smaller than it was on analog TV reception.

In our example, DTV signals travel 3 miles between the Transmitter and A-town’s home viewer. These signals also travel 2 miles to the wind farm where they will be partially reflected and then travel an additional 3 miles to A-town: a total path length of 5 miles. The reflected signals travel 2 miles further than the direct path so they arrive 12 microseconds later than the direct signal, causing a lagging echo.

Figure 2 shows the static echo rejection by early (2004-2005) US DTV ATSC receivers tested by the Mackenzie Presbyterian University (Brazil).

Figure 2: Single Static Echo ATSC

The 2004 vintage best receiver is shown in blue (ATSC Previous Generation). It provided excellent rejection of lagging echoes, but very poor performance in rejecting leading echoes. Shown in red is the best receiver vintage 2005 (ATSC Latest Generation) Here it appears that the design objective was to improve the echo rejection for leading echoes, but in doing so, the rejection of lagging echoes was compromised.

The Mackenzie Presbyterian University also tested static echo rejection of the best European DTV DVB-T receivers at the same time Those results are shown in Figure 3.

Figure 3: Single Static Echo DVB-T

Here we see that the DVB-T previous generation models (blue) behaved ideally for leading echoes up to – 75 microseconds, and equally well for lagging echoes up to + 75 microseconds. The DVB-T latest generation performs just as well over this range of echo delays and performs better for leading and lagging echoes > 75microseconds.

Comparing ATSC and DVB-T Receivers’ Echo Performance

The US DTV System (ATSC) relies upon digital signal processing (equalization) in the receiver to remove echoes from the television signal. There are multiple types, brands and generations of equalizers utilized within the US population of DTV receivers, with each generation of receiver showing significant advancement in its ability to reject multipath interference.

Following the US DTV conversion in 2009, the FCC released a report detailing their performance testing of 102 of the latest generation digital converter boxes [4]. The report states “Multipath performance of converter boxes was quantified using single-static-echo tests and field-ensemble tests. Single-static-echo performance of all approved converter boxes satisfied the ATSC guidelines within a small margin for measurement error (0.2 dB). The converter boxes successfully demodulated a median of 39 of the 50 ATSC-recommended field ensembles—with even the poorest performing converter box significantly outperforming 64 percent of FCC-tested receivers that were on the market in 2005 [4]”.

The 102 receivers contained 13 brands of demodulator chips. As the histogram in Figure 4 shows, the latest receivers were much better equipped to successfully demodulate signals containing multipath interference than DTV receivers manufactured in 2003 through 2005.

Figure 4. Field-Ensemble Histogram Comparison to Older Receivers

The FCC data also show the variability among the ATSC receivers with regard to their ability to successfully process echo rejection.

The European DTV system (DVB-T) does not rely on an equalizer in the receiver to reject multipath. DVB-T signals are modulated by a technique called Coded Orthogonal Frequency Domain Multiplexing (COFDM) Nearly 8,000 carriers are equally spaced across the channel bandwidth (e.g. 8MHz in the United Kingdom). Each carrier is digitally modulated at a very low bit rate. Carriers are about 1,000 Hz apart, so each symbol period is 1,000 microseconds. It is well known that nearly all signal reflections (echoes) arrive at the receiver within +/– 60 microseconds of the arrival of the same symbol. The beginning of each symbol period is reserved as a "guard interval" (typically 60us) during which receivers ignore the signal, so they do not "hear" echoes within this interval. This has the practical implication that the echo rejection of DVB-T receivers of different makes and model years are very similar among different manufacturers.

The DVB-T Standard provides the flexibility needed by the various governments in Europe to customize their broadcast signal to meet local propagation requirements. In a mountainous country such as Switzerland, the government chose a large guard interval to eliminate the effects of echoes. In Holland, a smaller guard interval suffices.

The United Kingdom has 8 MHz wide TV channels and Germany has 7 MHz wide signals. These variations are all encompassed by the DVB-T Standard. That is to say, every country in Europe has the flexibility to tailor its DVB-T system to accommodate its terrain and proximity to broadcasters in neighboring countries.

Static Echoes from Wind Farms

A static echo is generated by a TV signal reflected from the steel tower of a wind power generator. If the non-metallic blades are not rotating, they may cause some of the incident DTV signal to also be reflected to reach receivers, but echoes from today’s non-metallic wind turbine blades are very weak compared to reflections from the tower. The shape of these blades is optimized to capture as much energy from the wind as possible, that is, they are aerodynamically shaped; with tapered curved surfaces. To date, models to calculate the wind turbine blades’ reflected signal power have used rudimentary approximations. Results generated by these models have not been able to consistently predict actual field measurements [ 3 ].

Dynamic Echoes from Wind Farms

Although echoes from wind turbine blades are weak compared to reflections from the tower, dynamic echoes from rotating blades may be much more troublesome to DTV reception than echoes from static blades. Modeling of dynamic echoes is difficult because the Doppler frequency shift for signals reflected from the fast moving tips of rotating blades is much higher than the Doppler shift from the slower moving centers of the blades. European researchers have concentrated their studies on blades, but they also reported that the signal power reflected from the massive steel tower is significant. [ 3 ] While static reflected signals from the tower can be predicted with reasonable accuracy, more research is needed on predicting the dynamic echoes that are generated from moving blades.

Dynamic Echo Rejection Comparisons: ATSC vs. DVB-T

Pre 2005 ATSC receivers had good static lagging echo suppression, but poor static leading echo suppression (Figure 2). They also had good dynamic echo suppression. However, early experience with DTV broadcasting indicated that static leading echoes were more frequent causes of interference than dynamic echoes from rotating turbine blades. Consequently after 2005 the emphasis in ATSC equalizer design shifted toward better leading echo suppression, but at the expense of dynamic echo rejection. Figure 5 shows the dynamic echo rejection for a lagging echo of the best available ATSC receivers before and after 2005.

Figure 5: Single Dynamic Echo +8 µs delay ATSC

Good performance is indicated in Figure 5 when the trace is near the top of this chart. Static echo rejection is shown for zero Doppler frequency (top, center). The earlier ATSC receivers (blue trace) degraded slightly in dynamic echo rejection as the Doppler Frequency increases from zero to +/- 200 Hertz Doppler. The best of the latest ATSC receivers had very poor dynamic echo rejection as the red trace falls sharply at +/- 40 Hz. Doppler. In Figure 6, the same data is presented for the best DVB-T receiver.

Figure 6: Single Dynamic Echo DVB-T

Here the red trace shows the latest receiver performs much better to +/- 80 Hz Doppler. The earlier best DVB-T receiver was just as good, but only to +/- 35 Hz Doppler. These Doppler Frequency numbers are related to the maximum vehicular speed for autos. Doppler frequencies for echoes from wind farms depend on other variables. However good echo rejection (trace near the top of the chart) is always desirable and the DVB-T system provides this result over a wide range of Doppler frequencies for all receivers.

Predicting Echoes from a Wind Farm

There have been a number of attempts to predict the interaction of DTV signals with wind farms in Europe for the DVB-T signal. Results to date have not been satisfactory but this is only a work-in-process, largely in Europe [ 3 ].

Our ATSC signal was designed to maximize coverage for a given radiated power. In Europe the DVB-T standard was designed to allow neighboring countries to customize their signals and to optimize multipath rejection. The DVB-T system exchanges a loss in signal coverage capabilities for better echo rejection. Further research is needed on the development of predictive models for both standards.

Research and Development

It is possible to measure the relative echo rejection capabilities of a range of different ATSC and DVB-T receivers in a well equipped laboratory. The Charles Rhodes laboratory has 28 ATSC receivers of recent vintage. All these are fed Laboratory generated ATSC signals with various echo power and delays. The Rohde-Schwarz model SFE in this laboratory can generate either ATSC or DVB-T signals and it can simulate multiple echoes.

As mentioned above, there are about 13 different designs by as many firms of ATSC decoder IC devices. These designs offer different trade-offs between:

a) Leading echo vs. lagging echo rejection.

b) The range of echo delays that can be rejected.

c) The range of “Doppler Rates” that echo rejection works.

d) How strong an echo can be rejected vs. the echo delay.

In the A-town wind farm scenario of Figure 1, leading echoes do not exist where there is a direct path from transmit to receive sites. On the other hand, a direct path may not exist due to a man-made structure blocking the direct path (i.e. a multi-family residential structure or an office building). Under this scenario, lagging echoes will exist and the path length difference will be measured in miles, (6 microseconds of delay per mile of path difference).

With US DTV, an echo 100 times weaker than the direct DTV signal has no effect on the picture quality, for a single static echo. Put another way, the echo can be 100 times stronger with digital transmission than with analog transmission. We have measured the “degradation to reception” of the desired signal power due to a single static echo at 25% of the desired signal level for a range of 2008 vintage DTV receivers. These results are shown in Figure 7.

Nine ATSC receivers were tested. These are remarkably similar for delays below 30 microseconds. That echo would have killed analog TV reception. The average degradation to reception for an echo delay less than 30 microseconds is about 3 dB. [ 2 ]

Figure 7: Single Static Echo showed only a small reduction in received power (degradation to reception) due to an echo at 25% of the signal power

The signal degradation was, on average, about 3 dB, which except for the fringe area should be inconsequential. It is worth noting that all of the tested receivers behaved in the same way for echo delays under 30 microseconds, and some behaved approximately in the same way for even greater echo delays. These laboratory findings are directly applicable to the challenge of predicting interference to DTV reception by wind farms.

A wind farm will generate a large number of nearly equal power lagging echoes with slightly different delays. There would be no leading echoes. This is far from the typical echo ensembles used heretofore for testing in prototype receivers. Devising a suitable echo ensemble representing a wind farm would be a highly valuable addition to the literature available to both wind farm developers and receiver designers.

Summary and Conclusions for Digital TV

The DVB-T and ATSC systems were designed to achieve the objectives envisioned by their respective standards committees. The ATSC standard was designed to maximize signal coverage at a given power level and has seen several generations of demodulation circuitry improving upon the receivers’ ability to reject multipath interference. The DVB-T standard was designed specifically to give European Broadcasters the ability to customize their individual countries’ standards to optimize signal propagation within their markets and to minimize the effects of echoes upon reliable reception.

The data shows that the gap between the two standards’ ability to reject multipath interference has narrowed significantly since 2005. However, we would suggest that more field testing is required to determine the comparative performance of the latest generation of ATSC receivers with echo cancellation within a wind farm setting. Additional research and development is needed to create models to predict static and dynamic echoes within these settings. An outgrowth of this research would be to identify today’s best performing receivers and to use this information to help set receiver design, performance and manufacturing standards for echo rejection going forward.

FM Systems

FM reception is more robust to multipath than analog TV or ATSC digital DTV reception. Analog TV and ATSC DTV signals are amplitude modulated (ATSC DTV modulation is 8-level vestigial sideband (8-VSB), which encodes a binary stream as 8 amplitude levels of a carrier.) Multipath interference affects signal amplitude so analog TV and 8-VSB DTV demodulators are sensitive to it. Analog FM signals, on the other hand, which are frequency modulated, are unaffected by amplitude interference caused by multipath – up to a point. The FM demodulator locks on to the strongest signal in its capture range. As long as the multipath signal is sufficiently lower than the direct signal the FM receiver will ignore the multipath signal.

FM stereophonic signals are more susceptible to multipath distortion than are monaural signals, but this susceptibility is rarely if ever problematical to broadcasters. Stereo is enabled by in-band signals above the baseband modulation at reduced modulation amplitude. The baseband signal, which contains the sum of left plus right (L + R) audio channels, is single-side-band modulated with FM deviation bandwidth of 15kHz. The difference of left minus right (L – R) audio channel is double-side-band modulated with suppressed sub-carrier at 38kHz and FM deviation bandwidth +/- 15kHz. Between the top of the L+R channel at 15kHz and the bottom of the L – R channel at 23 MHz is a pilot tone at 19 kHz, exactly half the suppressed carrier frequency of 38kHz, which is used to regenerate the 38kHz subcarrier for the L – R demodulator. Because the pilot is at reduced amplitude(8% -10% modulation) relative to the baseband signal it is more susceptible than the baseband signal is to multipath interference. In practice, however, multipath interference to the stereo pilot tone is rarely a problem. When the pilot tone is lost, receivers automatically revert to monaural reception (L + R baseband only). Due to the limited dynamic range of modern, heavily processed FM Radio audio, most listeners cannot distinguish the loss of stereo.

The use of in-band subcarriers has been extended beyond audio to provide various data services. The most prominent is the Radio Data Broadcast System (RDBS), which uses a low-amplitude subcarrier at 57kHz. RDBS is a very narrow band system (1187.5 bit/sec.) suitable mainly for text. Although the low amplitude makes the RDBS subcarrier more susceptible to noise interference than the baseband FM signal, theoretically the low bit-rate would tend to at least partially offset this susceptibility to noise, including multipath. At the present time there is insufficient data available to predict the robustness of the RDBS signal to multipath from wind turbines.

Other in-band data services above 57kHz, which are referred to as Subsidiary Communications Authorization (SCA), have been and are being used. These include reading services for the blind, private data services, commercial music services and others. Little data is available regarding the robustness of SCA signals to multipath interference from wind turbines.

Digital radio is now being transmitted by many FM broadcasters. The FCC has authorized a hybrid system branded as “HD radio” (proprietary to iBiquity) in which digital signals are included in-band-on-channel (IBOC) with analog FM transmissions. The use of audio compression enables low data rate (typically 90–100 kb/s), which does not stress the available bandwidth and tends toward good signal-to-noise. The digital IBOC signals are low amplitude (10-20 dB below the analog carrier) but because the modulation method is OFDM (like European DVB-T), theoretically HD radio should be robust to multipath interference including that caused by wind turbines. Since digital radio is still new there is not sufficient data on which to confirm digital radio’s robustness to windmill multipath.

References:

[ 1 ] Influence of Echoes on Television Transmission, Pierre Mertz, Bell Telephone Laboratories, published by the Society of Motion Picture and Television Engineers, May 1953.

[ 2 ] Data from experiments in our laboratory dated October, 9th, 2010.

[ 3 ] [An Empirical Comparative Study of Prediction Methods for Estimating Multipath Due to Signal Scattering from Wind Turbines on Digital TV Services, by I. Angulo et al, IEEE Transactions on Broadcasting, June, 2011, Volume 57, Number 2, page 195.

[ 4 ] DTV Converter Box Program – Results and Lessons Learned, FCC Technical Research Branch, October, 2009

The Author

Charles W. Rhodes is a consultant in the field of television broadcast technologies and planning and is regular contributor to TV Technology Magazine. A number of television papers by Mr. Rhodes have been published by the IEEE, many of which have received awards for excellence.

Broadcast Wind

Broadcast Wind, LLC. is a consulting firm dedicated to providing engineering solutions to the broadcasting and wind energy industries.

This report shall not be duplicated, used, or disclosed - in whole or in part - without permission of Broadcast Wind, LLC

www.BroadcastWindLLC.com
Robert@BroadcastWindLLC.com

Road Trip - Iowa AWEA Distributed Wind Energy Conference

2011-09-19T00:02:00.003-04:00

Business partner, Frank Marlowe and I hit the road last week to visit with broadcast engineering professionals at the Chicago Radio Show and discuss AM radio / wind turbine interference and the latest theory in mitigation techniques.

Following our Chicago meetings, we drove to DesMoines to see what was happening at the AWEA Distributed Wind Conference. On our way through Illinois, we passed by the Council Bluffs wind farm.

Council Bluffs - On the Farm

The show was relatively small venue but chuck full of interesting new offerings within the distributed wind energy space. We raided the floor over a 5 hour period exploring new (and old) business offerings.

Frank (right) discussing WTG transport and installation with a Barnhart Sales rep (www.barnhartrenewables.com)

Brian Kuhn of Aeronautica Windpower (Right) takes a moment to pose for the camera. Aeronautica (http://aeronauticawind.com/aw/index.html) has begun shipment of their "Made in USA" 750 kW turbine to community wind projects across the country.

Brian Kuhn (right) of Aeronautica

How quiet is a wind turbine?

dB Comparisons

One of the booth rows at AWEA Distributed Wind Energy Conference

Start-up Japanese turbine manufacturer Tomo Wind Energy booth

Mike Kelly of Nordic WindPower took some time out of his crazed schedule to discuss their 2-blade 1 MW turbine, their next generation 1 MW turbine (due out in 2013), their Corporate HQ move to Kansas City and the powering of broadcast transmission facilities with wind energy.

http://www.nordicwindpower.com/products.html)

Mike Kelly of Nordic WindPower

Back in New Jersey we have been watching in wonder as our power company installs solar panels on our utility poles. The panels (made in China) feed a NJ manufactured inverter that, in turn, feeds the power to the grid.

Sepstar's foray into the renewable energy market takes the NJ idea several steps farther by introducing a Wind and Solar powered LED street light - complete with 5 nights of battery storage. The unit is made in China and priced around $2,500 per unit (excluding installation).

Sepstar 450 watt wind turbine integrated into hybrid LED street light

While Frank was off speaking to a Department of Energy rep regarding their renewable energy research programs, I stopped by the Bergey WindPower booth and spoke to Britton Rife about their new Excel 5 (http://www.bergey.com/) and the application of small wind turbines at low power TV and radio transmission sites.

We also sat down with Dwight Siman from Canadian start-up Vbine Energy (www.Vbine.com). Vbine is targeting the telecommunications industry with its new 5 kW permanent magnet VAWT selling for approximately $25,000 (excluding installation). .

Vbine 5 kW broadcast tower mounted VAWT

Following our visit to the show and a quick conversation with NREL's finest, Trudy Forsyth, we hit the road to Ames, Iowa to meet with Iowa State University and to talk about their renewable energy program.

A lot of driving, but a very productive week.

BroadcastWindLLC.com

Up Close - GE 1.5 MW WTG - Wind Turbines on the Farm

2011-08-21T11:24:00.004-04:00

The GE 1.5 MW Wind Turbine is one of the world's most popular utility scale WTGs. This past weekend, I had the opportunity to meet with a wind farm land owner, tour the grounds, and to experience a little bit of "life on the farm".

I recorded the video (below) to give you a sense for the sounds that come from one of the machines at close range. I used a Canon EOS 7D and a Rode stereo microphone (with a wind muff) situated about 20 yards from the base of one of the turbines.

The sound of crickets, the blades flexing and spinning in the wind, the whoosh of the air as the blades go by are all separately distinguishable. The camera's audio has an automatic gain control that was turned all of the way up for this recording. I was surprised by the relative quiet of the machine.

These are massive structures, standing nearly 400 feet above the ground at their highest point.

Stairs at the base lead to a doorway that the maintenance crews use to access the tower

Back at the house, sitting on the deck, we could hear the faint sound of the turbines spinning in the summer breeze.

The 8 year old facility, located near Waymart, PA, also presents an interesting case study on the RF interference that can be caused by WTG's to over the air TV households in the valley below and the measures that were taken by the wind farm developer to mitigate that interference using UHF repeaters.

BroadcastWindLLC.com

"Broadcast Wind" Awarded USDA Grant to Develop Renewable Energy Alternatives for Broadcasters in Rural America

2011-07-12T09:18:00.002-04:00

American Broadcasting together with wind energy technology present a tremendous, yet untapped revenue opportunity for small and middle sized farms across the nation. There are approximately 18,000 TV and FM broadcast transmitters distributed across the US. In the Midwest states, the majority of broadcast transmitters (each consuming between 100MWh and 1,500MWh annually) are located on or directly adjacent to farmland. Wind turbines may be sited on farm land surrounding these transmitters to the benefit of the farmer, broadcaster and the nation in general. The farmer’s benefit may be derived by utilizing a small portion of his land, and leveraging local, state and national incentives to purchase a wind turbine and sell all or part of the electricity to the broadcaster. Or, he may lease land to the broadcaster or a third party investment company for the development of a turbine project. In all cases, the local farmer, broadcaster and nation benefit by supplemental income, lower utility costs, and reduction of carbon emissions.

Before broadcasters will allow wind turbines to be sited near their transmitters the risks to their signal integrity must be removed. Rotating blades are known to introduce interference when turbines are located between transmitters and receivers. However, interference due to turbines sited at or very near a digital TV transmitter is relatively unexplored. Our objective is to characterize that interference and develop a set of guidelines for siting wind turbines near digital transmission facilities that will assure negligible interference. In our Phase I study, feasibility will be established by developing a basic engineering model and verifying it for a set of fixed variables by taking signal interference measurements of a transmitter situated near an existing turbine.
The result of our project will be a validated engineering guide that will enable the placement and design of wind turbines that will not interfere with the signals broadcast by co-sited transmitters.

There are approximately 1,200 TV and 2,600 FM transmitters in the 12 windswept Midwest states and another 14,000 transmitters in the remaining states (including Washington DC). Most of the non-Midwest states contain large regions with favorable wind conditions at transmitter sites (i.e. mountain tops, plains, etc.). This represents a total market of approximately $4.0B in the 12 Midwest states and up to $10B in the remaining 38 states. If fully realized, turbines serving all TV and FM markets have the potential to produce approximately 4 GW hours of renewable energy annually, which is equivalent to 8% of all wind power produced in the United States in 2008, thus eliminating 2.5 million metric tons of CO₂annually.

www.RobertMillerConsulting.com

2011-02-15T11:27:00.007-05:00

Broadcasting on Wind Energy
- Windustry Event – State College, PA

I recently had the opportunity to participate in a forum for Distributed Wind Energy, hosted by Lisa Daniels and the “Windustry” team at my Alma Mater, Penn State University, in State College, PA.

Attendees included half a dozen Wind Industry pioneers, site developers, turbine manufacturers, staff and students from 8 Universities, financial experts, municipal administration, and State and Federal funding agencies.

Brian Kuhn - Aeronautica Wind

Panel discussions covered turbine manufacturer product comparisons (I counted 4 US and 4 foreign manufacturers in attendance), wind project development, community education, permitting, financial planning and structuring, federal and state funding opportunities and national policy.

The following are some of my notes from the event:

Community education and involvement is frequently overlooked yet, it is a key first step to a successful project.

Roger Dixon

Every state, town, and utility presents unique challenges. Hire experts to manage your project! They pay for themselves over and over again by shepherding your project around the many traps.

Roger Dixon (right) of Skylands Renewable Energy fielded questions during a workshop on wind resources, and small wind systems economics.

Roy Butler

Roy Butler (right) of Four Winds Renewable Energy gave a workshop on wind energy measurement, its dynamics, and the mathematics behind analyzing field data.

Start the process as early as you can. Site wind data collection and analysis takes a long time and is relied upon heavily by the investment community (Broadcasters can save money by utilizing transmission towers to host measuring equipment).

There are significant Grant and Incentive dollars available (now) for renewable energy projects:

If you or your company start a renewable energy project in 2011 and finish it by the end of 2012 (guidelines apply here…), you may qualify for (1) a grant from the Federal Government equal to 30% of your capital expense and (2) utilization of MACRS and other accelerated depreciation incentives.

The USDA provides grant funding through the Rural Energy for America Program (REAP) for up to 25% of a project’s cost for small rural businesses (and Farms). They also provide loan guarantees of up to 80% of the project loan amount (for loans less than $5MM) through the REAP and the broader based Business and Industry (B&I) loan program. The B&I approval process has a faster turn-around. USDA loan guarantees mean much lower interest expense over the life of your project.

State and utility grants, credits, and tax incentives may contribute significantly to your project’s bottom line. Money for feasibility studies is also available in many states. Depending upon the circumstances, cash incentives can pay for as much as 50% of a project. Your state and utility renewable energy policies will also have a major impact on a project’s economic feasibility. The DSIRE database http://www.dsireusa.org/ is the best resource available to gather the specifics on your state’s incentives.

Tom Wind

Creative Financial structures are also available. For example, Tom
Wind, of Wind Utility Consulting, described the “Minnesota Flip” financial model that contemplates the investor owning the asset during the first several years and then passing ownership to the energy user (for very little money) once the tax benefits and / or initial financing terms have expired.

There were a number of discussions regarding the need for a long term national renewable energy policy. Many said that the current patchwork funding from Congress raises uncertainty, increases cost and represents one of the renewable industry’s biggest challenges.

The Policy Discussion

Policy concerns were echoed by former PA Secretary of Environmental Protection, John Hanger, as he addressed a lunchtime crowd:

US renewable energy policy is out of alignment with our national goals. Goals are currently left to state legislators. Some of our windiest states have infrastructures that restrict the development of renewable energy. We need a cohesive national plan.

70% of our oil is imported. Fossil fuel interests are vastly outspending renewable energy’s educational and lobby efforts. They are using widely circulated platforms (I.e. the Wall Street Journal’s editorial page) to spread misinformation and to effectively declare war on renewable energy.

Nearly one third of the 300,000 MW of coal fired utility plants in the US have no pollution controls whatsoever.

Enormous fossil fuel “subsidies” are woven into our nation’s fabric: our foreign policy, the cost of defending foreign oil fields, depletion of our fresh water sources, our income tax code and even, our health (I.e. the CDC reports that between 14,000 and 36,000 people die each year in the US due to NOX and SOX related poisoning).

A strong bi-partisan effort is needed to establish sensible long term renewable energy goals and standards.

Despite significant headwinds, renewable energy is growing and becoming less expensive. The US now represents 25% of the worldwide renewable power generation. Five years ago, solar energy cost approximately $10 per watt. It’s now $3.50 / watt. Wind energy was $6 per watt, and is now $2-3 per watt.

Our Company believes that broadcasting, farm and rural based towers and transmission systems are very well suited for distributed, renewable energy generation systems. Our mission is to research, encourage and promote the policies, and technical standards required to foster the growth of alternative energy within the broadcasting domain. Feel free to contact us to become involved or to add your voice to the cause:

http://www.robertmillerconsulting.com/

Wind Farms: TV and Radio Interference

2011-02-11T11:32:00.004-05:00

Over the past several years, wind turbine blade construction has advanced considerably, moving from an aluminum composition (prone to reflect and scatter radio signals) to a much more “radio friendly” construction of fiberglass composites. Despite these advances, “big wind farm” developers still face two challenges with signal interference:

1) Radar interference
Wind farm turbine blades are known to interfere with the radar tracking of weather systems and airplanes. The tip of a turbine blade may reach 170 MPH creating “doppler clutter” and cause the radar to misinterpret the data it is receiving. For example, a weather radar may reflect the wind shear between the fast moving blades as a tornado. An air traffic control radar, on the other hand, may temporarily lose track of an aircraft flying near to or behind a wind farm’s blades. In 2008, the Department of Homeland Security commissioned a study that stated “Despite these difficulties, there is no fundamental physical constraint preventing detection and mitigation of windmill clutter. The technologies of wind turbines and radar can coexist.” (http://www.fas.org/irp/agency/dod/jason/wind.pdf)

2) Digital Television and Radio Interference
Transmitter interference is driven by many variables including the TV receiver location in relation to the wind farm and the transmitter, the proximity of a wind farm to the transmitter, the frequency used and the receiver technology. Wind farms have been known to cause interference to over-the-air (OTA) digital television signals. A DTV signal passing through a wind farm turbines’ blades to a distant receiver can be met with issues inside the TV receivers’ internal circuitry causing pixilation, or no picture at all. Depending upon the projected level of interference, a wind farm developer may need to purchase cable or satellite services for neighborhoods whose OTA signal will be impaired following a wind farm’s construction. Click on this youtube video to see a clip from our latest DTV interference research : http://www.youtube.com/watch?v=qcTMQ1C3TEI&context=C329e979ADOEgsToPDskLiDaypwDS7pPZBQmLqx4Pp

While somewhat more resilient than DTV signals, microwave signals and their paths must be fully evaluated during a wind farm's planning stages.

AM radio transmission is highly susceptible to interference by turbine towers constructed close to the transmitter site. The rule of thumb for developers is to construct the turbine(s) at least 1 kilometer away from the AM antenna array (3 km’s for directional antenna settings). When you build a turbine close to an AM station you will also need to take worker safety precautions to prevent electrical burns. Take a look at this 1 minute video taken at a construction site < 1 km from an AM antenna: http://www.youtube.com/watch?v=iiirMEdiJQI&feature=plcp&context=C3145d56UDOEgsToPDskIrBDFS6gKJt2QimZehRcSn

Traditional (analog) FM radio is far less susceptible to wind farm interference, given the nature of the FM radio receivers’ circuitry.

This wind solar facility in Atlantic City, New Jersey has 3 FM stations co-located among the blades of the turbines. The stations' Chief Engineer reports that he has seen no interference issues in the 5 years that the turbines have been in operation.

Needless to say, all wind farm planning must include a complete RF interference study to identify all potential interference to RF, establish a solid baseline and to mitigate problem areas prior to construction.

Distributed Wind
Distributed wind typically involves a standalone turbine and has far less potential to cause radar, radio or TV interference. Small wind systems (less than 100 kW) are shorter and less massive and typically don’t affect military radar. Increasingly, small wind power is being deployed to power television, radio and telecommunications transmission sites. Companies like Ericsson, Vodacom and Motorola are researching and implementing wind power for the next generation of remote towers.

Some stations are already powering their entire transmitter operation on renewable energy. KRNG-FM serving Fallon, Nevada has it's 1.9 kW ERP transmitter situated 7,000 feet high on top of Two Tips Mountain. Utility power is not available here. The transmitter is powered soley by renewable energy including a 10 kW Bergey Excel wind turbine, a large solar panel and a battery room for energy storage.

The station occassional goes off of the air during prolonged periods of cloud cover and still winds.

Broadcast Wind is dedicated to providing engineering solutions to the Wind Energy and Broadcasting industries.

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Florical Automation Systems

2010-05-11T10:20:00.003-04:00

A Conversation with Florical’s Shawn Maynard:

I recently spent some time with my old NBCU colleague Shawn Maynard, (who is now) General Manager at Florical Automation Systems, discussing the company’s latest product offerings to Broadcasters and MVPDs (Multichannel Video Programming Distributors). While with NBCU, Shawn used Florical’s “Air Boss” to manage media within the owned and operated TV stations’ hubs in New York, LA and Miami. Today, he and his team are moving Florical and their time tested (at Univision, ABC and NBC O&Os, CNN, FOX) Air Boss into the world of cloud computing with Acuitas and Smart Central, giving Florical’s customers the ability to manage their media resources “virtually”, via the internet, from anywhere in the world.

Maynard: “Acuitas allows operators to centralize their master control and commercial playback functions without investing capital dollars in bricks and mortar”.

Maynard says, “We set out to create a system that dynamically hubs from anywhere, at any time. For example, if you are operating 20 television stations on Acuitas, any one of these stations can use Smart Central to become a virtual hub to all of the other stations in the group. Acuitas breaks down the silos among the local media distribution centers (or TV stations) and creates a platform from which the old hub model simply becomes part of a workflow shared, if desired, among these local centers. Automation needs to become invisible… not a task… just part of a system wide workflow where everybody picks up a piece of the chain.” Miami, for example, may serve as an HD content ingest center for the entire group, while Chicago may have the resources to cover Air and Server systems monitoring.

The system also addresses flaws found in the design of yesteryears’ fiber intensive, centralized hubs. In the early hub models, servers (and people) were housed centrally and media playback to local air was only as secure as the fiber that it was riding on. A New York hub to Chicago station fiber “backhoe fade”, for example, could leave local viewers watching a black screen while wreaking havoc on the station’s revenue (and reputation). With Acuitas, all automation software and content is housed locally on fully redundant raid 5 HP servers. If a component fails or if internet connectivity drops, the Acuitas system keeps your local media center on the air, seamlessly. The system issues real time exception reporting, email notifications on local systems health, missing content, post-air requirements and other user defined requirements.

Maynard states, “We have improved air safety, redundancy, eliminated fiber expense and given our customers the operational flexibility of cloud computing.”

Price comes as a pleasant surprise. Florical can fully automate a local media outlet with an HD play-out system, full “X/Y” redundancy with auto switchover, and about 60 hours of HD content storage for $120K per site. This is about half of what systems cost just two years ago.

A Florical customer can ease into the system and workflow by starting with a purchase of the Front-end. SD and/or “single thread” alternatives are available, giving media groups a $40K per site entry point, and the option to move into a fully redundant system as capital dollars become available.

Maynard says, “Smart Central is dynamic. It operates in a cloud. It’s a business model management tool. It gives a media company the ability to manage the chain within its own defined set of workflows and responsibilities. Nobody else offers this. Other automation company’s think in silos. Automation should be the ‘Microsoft Office’ of television, rather than silos. We’ve created an application for that.”

Florical will be offering EAS and School Closing capabilities later this year. “The system is downstream agnostic,” Maynard advises, “whatever the notification requirements are, the system can be tailored for each local market. “

Viewers and advertisers are setting the bar higher every day. They expect their local content to be presented in HD. Commercial and Public Television station groups, Independents, and MVPD’s are all facing the challenge of meeting these expectations in a time when Capital dollars are scarce. The introduction of cloud computing to the digital media management space presents a huge opportunity for these groups to not only respond quickly but to significantly reduce operating costs at the same time. Station groups can unite, forming a “critical mass”, combining their local HD commercial prep and playback functions within one co-op. PBS stations can combine program QC, media loading, playback and monitoring under one “virtual roof”. MVPD’s can upgrade their local avails to HD with centralized operations wherever they choose.

The virtual automation tools are here. The bricks and mortar are gone. Our imaginations (and a little investment) can do the rest.

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2010 NAB Show

2010-04-15T14:47:00.007-04:00

Great Show!!

Most of my time was spent learning more about the regulatory issues facing our broadcast industry (I.e. NBP, Spectrum and EAS). I also spent half a day on the floor checking on some (way cool) new technologies (Mobile DTV and 3D solutions were among the most impressive). I also had the opportunity to spend "face time" with old (and new) friends. I will focus here on the regulatory side of things...

Marcellus Alexander (NAB's EVP of TV and President of Education) and his team did another outstanding job putting this event together.

Monday began with a keynote speech by NAB President, Gordon Smith (he's also a former US Senator (Oregon (R)), laying into the FCC's National Broadband Plan (NBP) and the harmful effects that it may have on the future of television broadcasting. "Broadcasting is not an ATM machine that can keep spitting out spectrum", he said. [This] "appears to be an example of unnecessary government intervention when technology in the marketplace is already working through the issue."

Mr. Smith also addressed broadcaster's concerns with the FCC and retransmission consent, and the ongoing "performance tax" debate between the radio industry and the major recording companies saying that the tax was "basically a bailout of the major recording companies, three of the four largest of which are foreign owned. I think that the American people have had enough of bailouts" .

Our Monday morning gathering also included a tribute to one of my favorite people: Michael J. Fox, honoring his strength, courage, conviction and his work on finding a cure for Parkinson's disease. Mr. Fox's foundation has raised more than $175MM of research and development funding to help find a cure for this devastating disease.

NBP Discussion:

On the regulatory side of things, the FCC / Broadcaster Spectrum debate dominated NAB 2010. Among other things, Broadcasters have expressed the fear that the "Voluntary" spectrum auction outlined in the NBP was tantamount to being "given an offer that they can't refuse" by the FCC (paraphrasing a "Don Corleone" line from "The Godfather").

TV Spectrum Discussion: Use it or Lose it
MSTV President, David Donovan hosted a lively (Phil Donohue style) panel discussion - with standing room only - including panelists Phil Bellaria (FCC Broadband Task Force), Rick Ducey (BIA Financial), Paul Karpowicz (Meredith Broadcasting), and Lawrence Krevor (Sprint Nextel Corporation).

Some of the most heated discussion came with Mr. Donovan pressing Mr. Bellaria for specifics on the FCC's intentions with respect to the 120 MHz recapture, details on process and timing and an explanation on how the FCC could reconcile its 120 MHz goal with today's TV spectrum realities within the nation's most crowded markets.

Donovan said that most stations don’t want to give up spectrum and pointed to the NYC market housing 23 TV stations, 11 of which are broadcasting on channels 31 to 51. With FCC Commissioner Mignon Clyburn looking on from the audience, Mr. Donovan pushed Mr Bellaria for answers...: "How would you squeeze them into the channels below 31?" "Any idea of how many people would be impacted?" "Would Broadcasters need to change all of the digital TV maps?" "... then how would it work…?? " with FCC rulemaking scheduled for the 3rd quarter… before we have a full analysis of existing spectrum – isn’t this putting the cart before the horse? "

Mr. Bellaria, one of the bravest people in the room, advised the group that this was just the beginning of a long process; that the FCC had faith in the approach that the NBP laid out, that the FCC "did not want most TV stations to participate in the voluntary auction" as it "would not be necessary or desirable". He told the group (using a wedding day analogy), that all of the specifics could not be foretold on day one, but assured the room that issues and concerns will be worked out, in close cooperation with one another. He also said that the 3rd quarter rulemaking would concentrate on "enablers", dealing with VHF and other ancillary issues.

Tuesday morning began with a keynote speech by FCC Chairman, Julius Genachowski. Clearly, the Broadcasters' message was heard and the Chairman's speech got right to the point: "I have been compared to a well known unsavory character in the movies ("The Godfather" reference above).

The Chairman worked to connect with the audience, telling them about his background in broadcasting and about growing up in a strictly over the air television household. He told the group that he "respects the industry and understands all that they are going through" and that the National Broadband Plan was a "Win Win Win" for Broadcasters, Broadband Providers, and the American People.

The Chairman told the audience that times and delivery methods are changing rapidly and that his children are indifferent to the medium used to receive content. "Smart phones consume more than 30 times the spectrum of traditional cell phones, laptops consume 450 times, and internet demand over the coming 5 years will increase 40 fold". He told the room that the US is well behind 40 other developed countries on the spectrum planning efforts required to meet future demand and that our ability to compete, effectively, in the future is at stake.

Mr. Genachowski addressed certain "things written that are simply untrue", saying that there were "four points to be made":

1) Spectrum auctions are voluntary. Period.

2) We don’t need very many broadcasters to participate in the auction.

3) We anticipate a mechanism to minimize risk to broadcasters (I.e. reserve prices for auction)

4) The FCC will maintain an open and transparent dialogue with the broadcasters.

He also wanted to "dispel a number of myths":

1) Broadcast spectrum will be confiscated – Untrue

2) NBP will diminish voices, localism, etc. Untrue – the Plan gives funding to stations that need it, especially smaller stations in their markets - keeping them on the air.

3) NBP would prevent the growth of mobile DTV. Untrue - The FCC’s role is to enable new business models

4) Consumers would need to buy new equipment. Untrue - Simple re-scan required.

Mr. Genachowski told the audience that he was optimistic that the spectrum auction, as laid out in the NBP, will work and asked Broadcasters to avoid the "Beltway Tactics" and work constructively with the FCC going forward.

The Chairman also announced that FCC will convene an "Engineers Forum" in the coming months to "help the FCC develop the best path forward".

Interesting times!!

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