RF power comparison with a 3.5 mm coaxial thermoelectric sensor

Project Description

This comparison had originally been agreed as an EUROMET project including 6 participants. At the GT-RF meeting (June 20, 1999) this comparison was agreed to become a GT-RF key comparison (CCEM.RF- K10.CL). Fifteen institutions decided to participate in this comparison and all 6 participants of the EUROMET comparison joined the CCEM comparison.

The pilot laboratory (PTB) together with the two helping laboratories (ETL, JP and NRC, CA) prepared a technical protocol and a schedule. The comparison had started in July 2000 and till the end of 2001 twelve participants finished their measurements. After the measurements of the last participant both travelling standards failed, the reason of which is still unknown.

During the comparison the pilot laboratory was informed, that the countries of two participants of the CCEM key comparison had not signed the Convention du Mètre and therefore they were not allowed to participate in this (CCEM) comparison. It was planned that after the end of the CCEM comparison the present EUROMET comparison 525 with the two participants and furthermore PTB as the pilot laboratory will be added. During the CCEM comparison one participating laboratory asked for a later period of measurement and two laboratories (UME , SP) wished to join the CCEM comparison. As the duration of a CCEM comparison should not be extended to more than 1 1/2 year the two participants were asked to take part in the EUROMET comparison.

Since both travelling standards of the CCEM comparison have been damaged the two travelling standards must be now repaired and measured by the pilot laboratory. It is planned to finish the CCEM comparison now in January 2002 and to start the EUROMET comparison 525 with the repaired travelling standards in Spring 2002 with the 6 participants including NMI-VSL (NL) originally planned as the last participant of the CCEM comparison. NMI-VSL agreed to take part in the EUROMET instead of the CCEM comparison. Additionally NPL (UK) will take part in the EUROMET comparison in order that a second laboratory (besides the pilot laboratory ) participates in both comparisons. It is planned that the measurements of the EUROMET comparison with 7 participants will be finished within the year 2002. A combined CCEM/EUROMET Report A will be prepared.

Final Report 2007-12-11

The comparison has been completed and results are available in the KCDB.

The members of the meeting of the EUROMET RF expert group on 3 December, 1998 in Braunschweig agreed to carry out a comparison measurement with the topic of RF power measurement in the 3,5 mm line system. Because of the great number of interested participants it was later agreed to run two comparisons in succession with the same type of travelling standards :

1. the CCEM.RF.K 10 CL intercomparison with twelve participants. The measurements were completed in January 2002 with good results and the final report was finished in July 2006 and published in the Technical Supplement of METROLOGIA 43 in 2006.

2. the EUROMET comparison (GT-RF/99-2) with 8 participants from European countries only. The measurements started in May 2002 and were completed in June 2003. The ninth participant withdrew during the comparison because he had already participated successfully  in the first comparison. The two comparisons were linked to each other by two participants taking part in both comparisons. This EUROMET comparison provided quite good results, because only two of the eight participants had not fulfilled the condition for a good result En< 1 at one and resp.  two  frequencies. A Draft A report was sent to all participants in September 2004. In April 2007 the Draft B report was sent around to get the approval from  the GT-RF and the CCEM. The approval was obtained in June 2007.

Electricity and Magnetism (EM)
Dieter Janik, PTB (Germany)
Coordinating Institute
PTB (Germany)