The 20‐channel heterodyne radiometer of the Rijnhuizen Tokamak Project (RTP) measures microwaves in the range between 86 and 146 GHz. The spatial resolution is ∼7–16 mm parallel and 25–1300 mm2 perpendicular to the viewing direction, depending on the position in the torus. A waveguide network gives the opportunity to do alternate measurements of X‐ and O‐mode electron cyclotron emission (ECE) from the low‐field side (LFS) and X‐mode ECE from the high‐field side (HFS). A backward wave oscillator is installed at the HFS, for the purpose of measuring the electron cyclotron absorption (ECA) of the plasma. This set‐up also provides a possibility for fast relative calibration of the radiometer. To reduce the effects of multiple‐pass reflections and standing waves, Macor viewing dumps are mounted at both sides. A comparison of HFS and LFS ECE measurements during electron cyclotron heating will be given as a first result. First results of ECA measurements were obtained but will be presented in the future.

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© 1995 American Institute of Physics.
1995
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