Isotrope Links


NAB Engineering Handbook

David Maxson authored two chapters, 3.4 and 10.2,  in the recently published 11th edition of the NAB Engineering Handbook. Chapter 3.4 is about “Managing Workplace and Environmental Hazards“. Chapter 10.2 is about “AM Radio Equipment Performance Measurements“. The NAB Engineering Handbook is the definitive resource for broadcast engineers.

Read more about David Maxson and chapter 10.2 in an interview with David Maxson conducted by Radio Magazine editor Doug Irwin here.

You can purchase a copy of the NAB Engineering Handbook on the NAB website.

UTA FrontRunner Wi-Fi

Isotrope is pleased to have assisted the GBS Group on a project to improve the Wi-Fi on the Utah Transit Authority’s FrontRunner commuter rail:

The GBS Group Selected to Deliver Passenger Wi-Fi for UTAH Transit Authority on FrontRunner Trains

Utah Transit AuthorityVirginia Beach, VA – October 7, 2016 – The GBS Group, a systems integration and technical services firm has been given approval to complete delivery of their cellular and trackside RF passenger Wi-Fi system in place at the Utah Transit Authority (UTA) since early summer. UTA awarded a contract to GBS in late 2015 to design, install, and test a solution for their highly successful FrontRunner train which services passengers along a 90 mile corridor, centered in Salt Lake City and running as far as Ogden and Provo. After months of factory acceptance testing, GBS has been approved to complete the delivery to all FrontRunner consists by the end of the year.

“We selected The GBS Group based upon their demonstrated success as a systems integrator delivering custom, commercial rail solutions in the US, Canada, and overseas. GBS delivered a functioning test solution in May. Testing since then has shown great results along the entire corridor using cellular communications, augmented by 17 miles of trackside towers providing high bandwidth RF internet connectivity,” said UTA Manager of Technology Deployment Kyle Brimley. “We are thrilled that UTA chose The GBS Group to design and deliver such a complex project for their highly successful FrontRunner Service. UTA is an award-winning agency staffed by experts who have professionally engaged us to deliver a state-of-the-art Wi-Fi solution for their passengers and establish a digital train communication backbone capable of much more for UTA in the future” said Bob Golden, CEO of The GBS Group. “We are very proud of our amazing GBS employees and the world-class support companies that help us deliver time and time again”.

The GBS Team chose key partners to design and deliver this unique and complex Wi-Fi solution to the Utah Transit Authority. Core to the technology are train-to-ground, high throughput radio systems of RADWIN and an onboard multi-backhaul connectivity solution supplied by 21Net Ltd. Additionally, Isotrope, LLC, of Boston MA provides expertise in on-board and trackside radio frequency (RF) coverage analysis, antenna optimization, and wireless network consulting to the GBS Team to maximize network capacity available to passengers. Tabet, Inc. of Norfolk, VA manufactures precision, customized fabrication mounts, fittings and seals essential to the installation integrity of the project. The complete solution seamlessly integrates either cellular or trackside RF to give passengers the maximum possible internet speeds without interruption, at no cost to the passengers currently. The solution utilizes cloud-based application servers, hosted either outside or inside agency IT systems as desired. Remote Operations Support Systems (OSS) teams in Virginia Beach and Philadelphia monitor the performance of the system 24/7, 365, and work with local field engineers or technicians to upgrade or repair tower and train based systems.

About The GBS Group (GBS)
The GBS Group, founded in 2006, employs over 100 engineers, software developers, project analysts, controls and automation engineers solving problems for clients across the United States and Canada. GBS provides application and reliability engineering and custom hardware/software solutions for rolling stock health monitoring, passenger Wi-Fi, train station display and announcing systems for passenger rail agencies including Amtrak, VIA Rail Canada, Maryland Transit Administration, New Jersey Transit, Toronto Transit Commission, Utah Transit Authority and most recently Sonoma-Marin Area Rail Transit. GBS provides control and automation solutions for commercial and US Navy vessels, power monitoring and control software programming for Verizon Power in New York City, and dedicated engineers and analysts who support US Navy, Military Sealift Command and other engineering agencies servicing ships and vessels worldwide. GBS has multiple service contracts and personnel in Virginia, Washington DC, Illinois, California, Pennsylvania, New York, and Montreal.
For more information about The GBS Group go to

About UTA
Established in 1970, UTA has become a multi-modal transportation leader that is 100 percent accessible with a fleet of more than 600 buses and paratransit vehicles, 406 vanpools, 146 light rail vehicles, 63 commuter rail cars and 18 locomotives. UTA operates in seven counties along the Wasatch Front, including 45 miles of light rail in Salt Lake County and 90 miles of commuter rail from Salt Lake City to destinations in Utah and Weber counties. In 2015, UTA ridership was more than 46.6 million boardings. Visit UTA’s social media hub at

David Maxson to Present at NAB Show 2016

Isotrope’s David Maxson will be giving a presentation about 2 new kinds of interference in the FM band at the NAB Show 2016, Tuesday April 19th in Las Vegas. A preview of the presentation can be found in the NAB Preview edition of Radio World magazine. Read more here.

Automobile Key Fob Dead Zones in the News Again

David Maxson was interviewed by Fox-TV Chicago on the subject of car key fobs mysteriously not working in a certain area. The situation is similar to one David solved in Yonkers, New York. Here’s an excerpt from the story:

So what could be the source of that powerful interference? David Maxson is a wireless expert for the Isotrope company in Massachusetts.

“I’ve had about four phone calls from various places around the country. Yours might be the fifth,” Maxson said.

Maxson said some dead zones have been linked to shopping centers using radio signals to keep track of their shopping carts and reduce their theft. Another, he found, was caused by the light control panel used by a nightclub’s disk jockey.

“It was designed in a way that it was not sharing the spectrum properly with the key fobs. So it was preventing people from in front of the bar from being able to start their cars when they were ready to leave,” said Maxson.

Maxson said if your key fob does fail, try holding it as close as you can to the sensor it’s looking for, which might be the car’s antenna or the button you use to start your car.

See the interview here and you can read the full story here.


Comparison of Utah Wireless Broadband Speeds

In 2011 and again in 2013, Isotrope conducted a project that measured wireless broadband speeds for the State of Utah.  The project was funded by the State Broadband Initiative (SBI) of the National Telecommunications and Information Administration (NTIA). This past summer Isotrope prepared a Comparison Report, comparing the results from 2011 and 2013 drive tests.

An excerpt from the report:

Generally, there were several significant improvements in the availability of broadband service in Utah from 2011 to 2013. We see that 3G broadband speeds increased amongst all the carriers, perhaps in part by upgrading 3G technologies at the cell sites, and perhaps in part due to the upgrading of backhaul capabilities necessary to support 4G LTE at each cell site.

You may download the full report from the State of Utah Broadband Project here.

Defining “Public Safety Grade”

Isotrope has worked with Public Safety agencies in the past to recommend ways to harden their communications systems.  The Public Safety Telecommunications Council recently released a report “Defining Public Safety Grade
Systems and Facilities”.  The report focuses on the implementation of a Public Safety Broadband Network, i.e. Firstnet, but these standards and recommendations apply to Land Mobile Radio (LMR) communication facilities as well. A copy of the report can be found here.

Wireless Building Permits – A Cautionary Tale

One of the great existential conundrums is “How do you know what you know?”  I recently have seen a series of unrelated building permit applications for new or modified wireless facilities that were missing key information and the presenters firmly believed in the diligence of their submissions.  One thing these applications had in common (and not all applications are like this) was that the structural analysis was incomplete.

I read one application with a beautiful analysis of the integrity of the proposed camouflaged antenna mount.  It would hold together in the worst of hurricanes.  A note among many notes said that the analysis did not include analysis of the roof structure to which it would be attached because invasive techniques would be required to do so.  That means someone would have to cut open the flat roof and inspect the underlying joist work and wall connections.  Then a design would have to be created to ensure that the beautifully designed structure would not tear the roof off in the same hurricane. Yet the applicant’s agent and its attorney each firmly believed that all the necessary due diligence had been done and presented in the application.

In another case, a similar claim was made for attaching upgraded equipment to a water tank.  The mount was calculated and the notes indicated the tank was assumed to be in good shape and the existing studs welded to the tank were assumed to be up to the task.  The Professional Engineer stamped a letter certifying this.  Maybe if it is well-known that the tank and bolts are indeed within specification based on recent analysis or recent installation under construction control it might be OK to gloss over how the entire system will work. Not so here.

In this case, the error was compounded by the fact that two years ago, a modification that occurred did not look anything like what was proposed, and included a newly welded mount that had not received the tank owner’s approval or that of the Building Official.  Moreover, the existing mounts had missing studs, which the PE two years ago said should be repaired.  They never were.  So the new PE certification is based on a series of assumptions that a simple visual inspection would have contradicted.

This led to the “How do you know what you know?” question.  An eager project agent assured me that everything in the past had been done by the book, and not to worry.  Nothing would have gone on that water tank without proper structural analysis, owner approval and Building Official approval.  When I asked “How do you know?”  He got a bit testy and sputtered that his employer and the town would never have it any other way.  Digging into the history and making a site visit, I found he did not really know that which he firmly believed.

Then in another case, an applicant proposes to replace a one-foot wide flimsy guyed radio tower with one some seven feet wide, including new foundation and guy anchors.  The only structural analysis was in the form of a “typical” drawing of the new antenna mounts and a note that the tower design was yet to be determined, all with a PE stamp on the drawings.  Building officials are responsible for deciding whether a licensed contractor or a licensed engineer should be controlling construction and signing off.  They usually look for evidence the structural design and foundation design have been produced and signed for in advance of construction.  Construction control is the final step in ensuring the result will be structurally to code.  None of this was imposed by the Building Official.  The tail was wagging the dog on this one.  The antenna and mount would be just fine; never mind that there is a non-existent tower and foundation that will magically appear to hold them up.

In all three cases, the Building Official was unaware there was missing information.  A quick read of the documents would lead one to believe all was in order.  The one question Building Officials can ask when reviewing wireless building permit applications is in two parts: “Is this project going to be code compliant end-to-end when it is done, and how will we know?”

Isotrope has Moved!

As we get ready to start a new year, Isotrope is pleased to announce that we have expanded into new space. The move was a long one, about 30ft as we moved from one building to the other. Though we may miss the charm of the former space in a 300 year old house, we are excited about the new space as it will help us better serve our clients.

Our new address:

Isotrope, LLC
503 Main Street
Medfield, MA 02052


Your mileage may be different: Reflections on megabits per second and miles per day.

Read David Maxson’s article for “Above Ground Level Magazine” ( chronicling the Isotrope project that measured wireless broadband speeds for the State of Utah.  The project was funded by the State Broadband Initiative (SBI) of the National Telecommunications and Information Administration (NTIA).  In the article Mr. Maxson talks about theoretical wireless broadband speeds by wireless technology and how Isotrope went about measuring bandwidth speeds out on the roads of Utah.

Here is an excerpt:

With the officially defined threshold for broadband service (768/200Mbps) and an online broadband map showing data service availability by provider, the state of Utah sought other ways to look at the question. The Utah broadband website has an online speed test that broadband subscribers are invited to run. Such test tools provide a useful snapshot of data speeds that subscribers actually obtain where they use their broadband services (wireless and wireline). Of course, the results are entirely dependent on who runs the speed test, the quality of their connection, and the type and condition of their user equipment.

To obtain another glimpse at the geographic distribution of mobile wireless broadband services, the Utah SBI team commissioned a statewide drive test of broadband mobile wireless services. To guide the drive test, Bert Granberg of the Utah Automated Geographic Reference Center (the state’s geographic information systems department) assembled a set of first-, second- and third-class roads spanning the state’s varied terrain and land use. The plan was to reach into every corner of Utah life, including urban, suburban, rural, mountain, valley, canyon, desert, park, range, resort and reservation. Isotrope won the contract to conduct the survey under the auspices of the state’s broadband consultant, International Research Center. Utah is a beautiful place to tour, even if just passing through.

Read the full article here.

Isotrope Drive Testing Services

Isotrope now offers comprehensive in-house drive testing services.   Our carrier class test gear measures CDMA, 1xRTT, EVDO, GSM, GPRS/EDGE/UMTS, HSPA and LTE technologies.   Isotrope provides benchmarking of data as well as voice calls.  The test platform, combined with our carrier class signal propagation modeling software, provides comprehensive benchmarking services.  In addition to measuring outdoor wireless signals for macro cell and DAS, Isotrope is also equipped to do indoor DAS benchmarking.

Contact Isotrope for more information.