From August 1995 to September 1998, the CCEM-K6.c Key Comparison (which started as the CCE 92-05 comparison) of ac–dc voltage transfer standards at selected high frequencies between 1 MHz and 100 MHz was carried out. Subsequently, from December 1998 until mid 2000, some participants carried out additional measurements.

Two travelling standards were measured by 15 national standard institutes. The results at all selected frequencies in the range from 1 MHz to 100 MHz show a good agreement between most of participants. The agreement at 1 MHz is within 10 µV/V for most of the participants. The span of the majority of the reported ac–dc differences at 50 MHz is less than 0.6 mV/V, which is similar to a previous comparison but with more participants. Even at 100 MHz, most obtained results are within a span of 3 mV/V, which is considered to be a good agreement.

Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the Mutual Recognition Arrangement (MRA).