Shashkov, Ya.V. Bazyl, D.S. Calaga, R. Donetskiy, R.V. Lalayan, M.V. Sobenin, N.P. Zavadtsev, A.A. Zobov, M. JACoW Geneva, Switzerland 978-3-95450-178-6 10.18429/JACoW-SRF2015-THPB104 English 1394-1396 THPB104 HOM cavity damping simulation higher-order-mode Contribution to a conference proceedings 2015 2015-12 http://dx.doi.org/10.18429/JACoW-SRF2015-THPB104 http://srf2015.vrws.de/papers/thpb104.pdf In the frameworks of the High Luminosity LHC upgrade program an application of additional harmonic cavities operating at multiples of the main RF system frequency of 400 MHz is currently under discussion. The 800 MHz superconducting cavities with grooved beam pipes were suggested for implementation. A scaled aluminum prototype with a frequency of the operational mode of 2400 MHz was manufactured for testing the results of simulations. The load reflection coefficient measurements were performed as well as the Qload measurements for cavities with the load. Here we discuss the prototype design and report the obtained measurement results.