A New & Improved Standard for Unlicensed Transmitters? - C63.10-2013 Review

Dan Crowder, TCB Supervisor

Today's Elite Expert is Dan Crowder, our Certification Department Supervisor and FCC/CE Mark Team Leader.  As a senior EMC Engineer actively involved in transmitter standards development--including ANSI C63.10 and ANSI C63.26, the TCB Council, and the IEEE EMC Society, Dan's seen his fair share of transmitter issues and solutions. Read below to see what he has for us this week.

C63.10-2013 was released back in September and has received quite a bit of praise – but it has some caused some controversy as well.

The purpose of C63.10 was to put all the test methods for unlicensed transmitters into one document. The first version of the standard was released in 2009 and included what was considered to be “non-confrontational” test methods. The standard was adopted by the FCC and Industry Canada for the testing of unlicensed transmitters. Four years later, version two has been released and includes the so called “confrontational” test methods.

The standard covers every type of transmitters that fall into the unlicensed category. The test methods have been gathered from a multitude of resources including the FCC, Industry Canada, manufactures, test laboratories and certification bodies from around the world.  Very detailed instructions have been provided for some very complicated transmitters including digital transmission systems that include transmitter power control and dynamic frequency selection. These procedures were only published in various FCC knowledge database documents that were sometimes tedious to dig up.

Another useful tool is a reference table included in Annex A. The table steps through the FCC Part 15 rules one by one and cross-references sub-clauses in the standard to point out specific tests that pertain to the specific rule part.

This standard along with C63.4 can be used as test methods for almost every unlicensed transmitter.

As a test laboratory, you should lookout for procedures that have not been adopted by the regulating bodies. One that stands out in my eyes is the formula for distance correction factor for frequencies below 30MHz.

Overall, C63.10-2013 is a huge improvement over any previous document or documents for test procedures for unlicensed transmitters.

Do you have any questions about transmitter standards, certification, or other related topics? Please share your comments or questions below and our expert, Dan Crowder, will get back to you.

Join us for the series premiere of Ask An Engineer!

The premiere of Elite’s new web series, Ask An Engineer is finally here! Click on Episode 1 to check it out. Every month we get our veteran EMC engineers out of the lab and in front of a camera to answer your EMC and tech questions. Join the discussion at our twitter account and send us your questions @EmcElite, or send us an email at EMCElite@elitetest.com. 

Ask us anything – just make sure it’s topical and related to EMC and the tech industry.  We look forward to hearing from you!

EMC Sleuth: Mysterious Interference at the Doctor's Office

Ray Klouda, Elite President

Today's expert is Ray Klouda, Elite’s President and captain of this ship. Ray has 34 years of experience in the related fields of electromagnetic compatibility (EMC) and RF shielding design with a focus on military and commercial EMC specifications, quality systems, and TCB Certification.  As Membership Officer of the IEEE EMC Society’s Chicago Chapter and active member of the American Council of Independent Laboratories (ACIL) and various Smart Grid committees, he likes to stay involved in the industry and act as an “EMC Sleuth” if the occasion arises. Read below to see what he has for us today.

Sometimes, I have the fortunate opportunity to step outside of the EMC lab and investigate real-world EMI problems.  Several years ago, I received a call from a desperate general contractor who had an EMI situation in a new state of the art audio clinic.  The facilities included an MRI suite in the lower levels.  The doctors complained about issues of networking errors with their new computer system, electronic noise problems in their audio lab, and incorrect results from their blood analyzers.  They were threatening to withhold payments until the issues were resolved.  

The GC’s first thoughts were that the MRI equipment was the culprit.  He called us in the survey the site to determine if the MRI was indeed causing these interference problems.  We arrived at the site and set up a spectrum analyzer with various antennas and current probes in order to monitor the field intensity levels.  We started by taking measurements in the MRI suite and then moved on to the audio labs where the equipment problems had occurred.  

In a short time, we were able to diagnose the problem.  The interference was due to a broadband source.  We could see significant broadband switching noise throughout the high frequency (HF) spectrum.  These voltage spikes were both radiating from the power lines, as well as, conducting into the power lines.  We could not attribute any significant RF interference as generated by the MRI equipment.  We proceeded to walk into the waiting area of the office where the levels intensified.  This waiting room was state of the art and included high tech lighting that dimmed to create a soothing and relaxing atmosphere. 

Can you deduce what else the light system created?

At an opportune time, we turned off the lights in the waiting room.  We immediately noticed a significant drop in the HF noise level and the spikes all but disappeared.  The contractor was beside himself to think that such a low tech device as a dimmer switch could wreak such havoc upon the doctors’ offices.  We recommended that the dimmers be replaced with dimming technology that does not produce noise.  The problem was solved and everyone was happy.

Below are some questions for further thought and discussion on real-world interference applications:

What lighting technologies are significant sources of EMI?

What are some ways to reduce this interference?

Will interference problems increase as more high tech lighting is installed to reduce energy consumption?

What regulations are in place to control the level of interference from these sources?

Do you have answers to the above or any questions about Interference Issues, EMC Testing, or other related topics? Please share your comments or questions below and this week's expert, Ray Klouda, will get back to you as soon as possible. 

4 Things to Look For When Interpreting Standard Requirements

Craig Fanning, EMC Lab Manager

Today's Elite Expert is Craig Fanning, our EMC Lab Manager, US National Committee Technical Advisor for CISPR-D, and advisor on many other industry committees. Read below to see what he has for us this week. 

 

Being on several standards committees, I get a lot of questions about how to interpret the information provided in standards and specifications. Sometimes this is from a colleague who is thoroughly reviewing a specification in preparation for a quality audit. As a result of the thorough standard review and the possibility of being assessed a “deficiency” during the audit, they become overly concerned about all parts of the standard. Other times, the person has already been audited and overlooked a requirement. This resulted in a “deficiency” during the audit. The standards committees have content rules (what is and is not a requirement and how is that defined in the standard) that must be followed when a standard is being developed or revised. In addition, quality auditors are only supposed to audit against the requirements of a standard. Here is brief summary of what is a requirement within a standard…

1. Main Body of the Standard: In general, information provided in the main body of the standard and prefaced with the word “shall” is a requirement. Dimensions and values are also a requirement. If no tolerances are provided in the standard, then general tolerance rules apply (or the tolerances specified in the base standard of a series of standards would apply). Any information prefaced with a should, could, may, etc. (anything other than a shall) could be considered informational and not a requirement. 

2. Notes: Notes in a standard are for information purposes only. You will notice that notes within a standard do not contain the word “shall”. Do not confuse “Notes” with “Footnotes”. Notes will always be prefaced with the word “Note:” Footnotes are used many times in tables and can contain very important information. So pay close attention to footnotes (especially in tables).

3. Annex (Normative or Informative): At the beginning of each Annex (sometimes referred to as Appendix in some standards), the word “Normative” or “Informative” will appear. If the Annex is “Normative”, then the information in the annex is a requirement (again keeping in mind the preface word of “shall”). If the Annex is “Informative”, then the annex is for information purposes and is not a requirement.

4. Interpretations: Although the standards committees try to make the information provided within a standard as clear as possible, something always seems to get into the published standard which may need interpretation or clarification. In these instances, the reader will have to use good engineering judgment. When this happens, it is a good idea to ask others in the industry (especially persons on the standards committee responsible for the standard generation) how they interpret the information provided in the standard. They most likely have had the same question and have addressed the issue.

I realize that this is a “crash course” in standards interpretation, but it should provide someone with the basics for interpreting standards. Knowing the basics and what to look for in a standard (also what can and cannot be audited) can really be helpful during a quality audit.

Do you have any questions about EMC Standard Interpretation, EMC Testing, or other related topics? Please share your comments or questions below and this week's expert, Craig Fanning, will get back to you as soon as possible.