Leadership Team

The ESC Spectrum leadership team’s diverse experience extends across different decades, industries, universities, and roles. What do they all have in common? A passion for helping customers succeed. The ESC Spectrum team helps customers at facilities across the U.S. comply with air emissions compliance regulations, save time and resources, and solve challenging issues so they can maintain focus on their core business.

Meet Our Leadership Team

Jeff Rabensteine

Jeff joined ESC Spectrum in 1988 and has served in many capacities including Engineering, VP of Marketing & Sales, VP of Customer Support, VP of Operations, and Executive Vice President. His diverse experience has led to a rich understanding of the regulatory landscape and business challenges that our customers face. He has served the industry through participation in a variety of ASME committees and EPRI task groups. Jeff graduated from The University of Tennessee in 1990 with a B.S. in Electrical Engineering.

Rachel Morgan

Executive Vice President
Rachel joined ESC Spectrum over two decades ago as a Software Support Specialist. She has assumed many roles over the course of her career, including Director of Customer Services and VP of Development and VP of Customer Services. She currently serves on the as the Executive Vice President, and oversees Support, CEMS Services, CEMS Manufacturing, CEMS Training, Software Implementation & Support and Software Development departments. Rachel graduated from the University of Tennessee in 1999 with a M.S. in Computer Science.

Michael Viator

Vice President, Sales and Marketing
Michael joined ESC Spectrum in 2016 as the Director of Sales, Business Development and Marketing. He brings over 30 years of business development experience in the software, instrumentation and automation field. He has vast expertise that includes leadership roles in capital project management, global sales and environmental regulation and reporting.  He has an MBA from Rice University, a Business Management degree from University of Texas - Austin, and an Industrial Technology degree from Sam Huston State University. 

Mark Shell

Chief Technology Officer
Mark has been with ESC Spectrum for almost 40 years and has been involved in many roles. He was ESC Spectrum’s first Project Implementation Engineer. He wrote most of the code used in the 8800 datalogger. and designed the hardware for both the 8800 and 8816 Data Controller. As Chief Technology Officer, he guides the technical direction of the company, and oversees StackVision Software Development, Controller Development, and Product Management. Mark graduated from the University of Tennessee with a B.S. in Electrical Engineering in 1982 and M.S. in Electrical Engineering in 1986.

Brian Fowler

Director of Operations
During his decade plus tenure at ESC Spectrum, Brian has held a number of different positions giving him a unique perspective. He began in Software Implementation before promoting to Director of Engineering and Marketing, a role in which he oversaw all engineering operations and managed promotional activities. In his Operations role, he oversees the Sales Support, Project Engineering, Customer Service (Tier 3), and Controller Production departments. Brian graduated from the University of Tennessee in 2001 with a B.S. in Electrical Engineering and an M.B.A. in 2011.  

Deb Stock

Director of Human Resources
Deb brings over 20 years of Human Resources experience to ESC Spectrum. Prior to joining the team, Deb worked in a variety of industries which include manufacturing insurance, banking and healthcare. She has experience in strategic human resource planning, employee engagement, performance management and more. Deb holds a Master's in Human Resources from Penn State University and two HR certifications: Senior Professional Human Resources (SPHR) and Senior Certified Professional in Human Resources (SCP-HR).

Jesse Harlan

Director of Finance and Administration
Jesse joined ESC Spectrum as the Director of Finance & Administration in 2019. He is responsible for Finance, Accounting, Facilities, and IT Support. Prior to ESC Spectrum, Jesse led teams in accounting and finance in diverse areas of Exelon Corporation for about thirteen years. Jesse is a C.P.A. and graduated from the University of Baltimore in 2003 with a B.S. in Finance and obtained an M.B.A. with an Accounting specialization from Loyola University Maryland in 2006.

Eric Prater

Manager of Engineering
Eric joined ESC Spectrum over a decade ago as a Systems Implementation Engineer. He has since worked as an Engineering Manager and currently serves as the Manager of Engineering. In his roles, he has implemented numerous StackVision Data Acquisition Systems of all sizes, including fleet wide installations. Eric’s previous experience includes programming at many industrial automation integration providers. He graduated from the University of Tennessee in 1999 with a B.S. in Industrial Engineering. 

Harvey Fierro

Manager of Customer Services
Harvey joined ESC Spectrum in 2013 as a System Support Engineer, then was promoted to Manager of the Customer Services group in 2018, a role in which he manages a staff of 16 customer support and reporting team members. Harvey has over 25 years of experience in the CEMS environment in various projects and roles. Before joining ESC Spectrum, he was a Field Service Representative with Teledyne Monitor Labs for over 20 years.

Risheng Lin

Software Development Manager
Before coming to ESC Spectrum to serve in the Software Development Manager role, Risheng had extensive experience delivering high quality enterprise and cloud software products in the fast-paced technology industry. Risheng manages all aspects of the development lifecycle (SDLC) from design through customer relationship to ensure achievement of business objectives. Risheng graduated from Shanhai Jiao Tong University with a B.S. in Business/Managerial Economics. He then obtained a M.S. in Computer Science and a Ph.D. in Mechanical Engineering from The University of Toledo.

Jennifer Shelian

Manager of Customer Success
Jennifer joined ESC Spectrum in 2002 after graduating from Lewis University with a BS in Computer Science and a minor in Mathematics. She resides in Tennessee and hails from outside of Chicago. Jennifer began working in Customer Support and has worn many hats including reporting specialist, system implementation engineer, and project manager. Her experience lends the perfect backdrop to her current role as the Manager of Customer Success.

Mark Gerhauser

IT Manager
IT Manager Mark Gerheauser joined ESC Spectrum with a wealth of experience in technology systems. While in the Army, he served as an electronic warfare technician in Germany, Turkey, Okinawa and Korea. He has close to three decades of experience with Cisco network, security and voice system engineering. In his previous role, he managed network/voice systems for a large hospital and doctor clinic system in Houston, Texas. Mark, a father of two, enjoys spending time with his grandchildren and performing with his band.

Bobbi Greenwalt

CEMS Integration Manager
Bobbi started in electric power generation industry 15 years ago as an Instrument and Control Specialist for Minnesota Power. She advanced to CEMS Lead Administrator and provided leadership and support to Minnesota Power’s thermal generation CEMS technicians to ensure accurate and reliable CEMS operations. Bobbi came to ESC Spectrum as a Proposal Engineer and has since been promoted to CEMS Integration Manager. She now oversees all CEMS operations at ESC Spectrum. Bobbi holds an A.A.S in Electrical and Industrial Automation and a B.A.S. in Applied Engineering.

Dennis Myrick

Service Manager
Dennis began at ESC Spectrum in 2001 as a Field Service Engineer. He transferred to the Central Florida area in 2004 to support the area facilities as the onsite area Service Engineer and has recently been promoted to Remote CEMs Service Manager. During his time at ESC Spectrum, Dennis has completed numerous field operations, including troubleshooting CEMS DAS projects. Dennis’ experience prior to joining ESC Spectrum includes serving on-board a U.S. Naval submarine in Pearl Harbor. Dennis graduated from Naval Nuclear Power School in 1996 as a Nuclear Trained Electronics Technician and Reactor Operator.

Tanya Circle

Human Resources Manager
Tanya Circle joined the ESC Spectrum team as an HR Manager in 2021 after just under a decade of experience in the Human Resources field. She obtained her Master of Science in Industrial and Organizational Psychology in 2015 from Emporia State University in Emporia, Kansas (Go Hornets!) and currently holds a Professional in Human Resources (PHR) certification. Tanya has a passion for assisting others and supporting positive, engaging work cultures.

Mike Sepulveda

Testing Manager
Michael joined ESC Spectrum in 2020 coming with a strong history of stack testing, along with being recognized as a Qualified Source Testing Individual (QSTI) by the Source Evaluation Society. He resides in Pensacola, FL and hails from outside of Los Angeles, CA. Michael came aboard to grow the testing team, and since then, taken on many roles, including site lead, analyzer specialist, and mercury analysis specialist. His experience lends the perfect backdrop to his current role as the Testing Manager.

Daniel Frome

Senior Systems and Database Administrator
As a Senior Systems and Database Administrator, Daniel Frome manages hosting, server management, FlexReports, SQL server and serves as a StackVision Business Analyst. He is a subject matter expert for many products and a “master problem solver” who provides guidance concerning development and support issues. Daniel earned his B.S. in Computer Science from Maryville College with a minor in Economics and Statistics and an M.B.A. from East Tennessee State University (ETSU), where he met his future wife. Daniel is also is a working Dad who helps coach baseball and basketball for both of their children.

Shaun Ellis

Senior Product Manager
Shaun Ellis is a Senior Product Manager at ESC Spectrum with over two decades of Continuous Emissions Monitoring Systems (CEMS) experience. Shaun is known for resolving tough questions and supporting customers to the fullest. His customer-centered point of view informs software development for many different products. Shaun also was the lead business analyst over the design, development, and installation of QAInsight. Shaun started his career at ESC Spectrum in 1999 after receiving his Associate's degree in Electronics from the Tennessee Institute of Electronics. Shaun is passionate about customers' needs when using ESC Spectrum’s products.

Anthony Dougherty

Senior R&D Manager
Anthony has been with ESC Spectrum for 12 years and has worn many hats during that time including Project Engineer, StackVision Business Analyst, StackVision Development, Customer Success Engineer, Senior Product Engineer, sole developer of DLSuite and now the Senior R&D Manager here at ESC Spectrum. As Senior R&D Manager Anthony reports directly to the Chief Technology Officer of ESC Spectrum and is responsible for all development efforts related to the 8864. Anthony is responsible for and is heavily involved in all development aspects of the 8864. Anthony Graduated from the University of Tennessee with a B.S. in Electrical Engineering in 2000.

Margie DiLoreto

Accounting Manager
Margie worked in healthcare for more than twenty years before coming to ESC Spectrum in December of 2019. She graduated with her Master’s in Accounting from the University of West Florida and has extensive experience building teams of high performers in a dynamic industry, which included multiple software conversions, acquisitions, and numerous changes in regulatory and reporting requirements. Margie’s goal is to perfect the efficiencies of work flows and processes at ESC Spectrum, while developing the staff to better serve their internal and external customers.

Anna Wilson

Corporate Marketing Manager
Anna Wilson joined ESC Spectrum in 2020 as a Corporate Marketing Manager with over 20 years of experience in the energy industry. She is well-versed in branding, leadgen, communications, GTM strategy, content marketing, and project management. Previously, Anna served as the Corporate Marketing Manager for American Innovations, a supplier of solutions for the oil and gas industry. She spent a decade as a music journalist for magazines, the Austin-American Statesman and Riverfront Times. She graduated with a BA in English Literature from Washington University and a Masters in Literature from University of Missouri-Columbia. Anna is a Missouri native and an honorary Texan.

Ramona Fischer

Accounting Manager
Ramona Fischer began with ESC Spectrum in 1989 and worked for over a decade before leaving to be a full-time mom. After returning to the workforce, she was an Accountant and Office Manager for a structural engineering firm and served as a Director's assistant for the Escambia County School District. Ramona returned to the company in 2013 as an Accountant, and is now the Accounting Manager. She earned a BS in Accounting with a minor in Finance from The University of West Florida in 1987.

Join the ESC Spectrum Team!

From The Source Blog

CEMS Audit Prep Checklist

Quick CEMS Audit Prep Checklist

Use our quick checklist to pass an EPA CEMS audit of your facility. Use a proven CEMS DAS like StackVision and Prism for critical data and have current information about your designated representative, record keeping, QA/QC plan, permit & acid rain program at hand.

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