Side-by-Side Comparison of Receiver Studies

NAB Receiver Study Other Receiver Studies
# of radios
  • 28 radios
    		•
  • CEMA - 16 radios
  • FCC - 21 radios
  • National Lawyers Guild - 11 radios
    • Type of radios
  • Tested eight car radios, five clock radios, five components, five personal radios and five portable radios.
  • According to 1998 sales data - clock, personal and portable radios made up 65.3% of the total radio sales. Components make up 14.1% and car radios make up 20.5%.
  • CEMA - Did not test clock radios and only tested one personal radio. Tested five car radios, five components and five portable radios.
  • FCC - Did not test clock radios or personal radios. Tested primarily car radios (7) and component radios (9) with five portable radios.
  • National Lawyers Guild - Only tested one clock radio and one personal radio, four component, three portable radios and two car radios.
    • Type of radios
  • Used the International Telecommunications Union-Radiocommunication Sector (ITU-R) interference standard (i.e. signal-to-noise ratio of 50 dB).
  • CEMA- Used a signal-to-noise ratio of 45 dB as its interference reference. That ratio was established as a minimum for quality broadcasting in a NPR report filed in MM Docket 87-268.
  • FCC - Tested its radios for distortion. It increased undesired signals until distortion increased 1% and 3% from baseline levels.
  • National Lawyers Guild - Did not establish an interference standard. The study reported a "transition zone" for each radio where the injection of undesired signal caused the radio to fail.
    • Conclusions
    • NAB tested the most radios and tested several in each category. NAB's radios fairly represent the radios sold in 1998. Omitting categories or testing only one or two radios in a category does not provide adequate data on which to base sound conclusions.
    • NAB and CEMA used accepted interference standards as baselines for each study.
    • The FCC did not have any reasoning or justification for its methodology and there is no indication that measuring distortion shows when interference that would bother a listener would occur.
    • The National Lawyers Guild testing demonstrates when a radio fails to receive a signal, but does not fairly represent the point at which unacceptable interference will result. Unacceptable interference occurs before a radio fails to receive a desired signal.