GROPPERA RADIO AG AND OTHERS v. SWITZERLAND JUDGMENT 24 European supervision covering both the legislation and the decisions applying it; when carrying out that supervision, the Court must ascertain whether the measures taken at national level are justifiable in principle and proportionate (see, as the most recent authority, the Markt Intern Verlag GmbH and Klaus Beermann judgment of 20 November 1989, Series A no. 165, pp. 19-20, § 33). 73. In order to verify that the interference was not excessive in the instant case, the requirements of protecting the international telecommunications order as well as the rights of others must be weighed against the interest of the applicants and others in the retransmission of Sound Radio’s programmes by cable. The Court reiterates, firstly, that once the 1983 Ordinance had come into force, most Swiss cable companies ceased retransmitting the programmes in question (see paragraph 18 above). Moreover, the Swiss authorities never jammed the broadcasts from the Pizzo Groppera, although they made approaches to Italy and the International Telecommunication Union (see paragraphs 39-42 above). Thirdly, the impugned ban was imposed on a company incorporated under Swiss law - the Maur co-operative - whose subscribers all lived on Swiss territory and continued to receive the programmes of several other stations. Lastly and above all, the procedure chosen could well appear necessary in order to prevent evasion of the law; it was not a form of censorship directed against the content or tendencies of the programmes concerned, but a measure taken against a station which the authorities of the respondent State could reasonably hold to be in reality a Swiss station operating from the other side of the border in order to circumvent the statutory telecommunications system in force in Switzerland. The national authorities accordingly did not in the instant case overstep the margin of appreciation left to them under the Convention. C. Conclusion 74. In conclusion, no breach of Article 10 (art. 10) is made out, as the disputed measure was in accordance with paragraph 1 (art. 10-1) in fine and satisfied the requirements of paragraph 2 (art. 10-2). III. ALLEGED VIOLATION OF ARTICLE 13 (art. 13) 75. In their original application Groppera Radio AG and Mr Marquard, Mr Fröhlich and Mr Caluzzi also relied on Article 13 (art. 13) of the Convention, claiming that they had not had an "effective remedy before a national authority" in order to have it determined whether Article 78 § 1 (a) of the 1983 Ordinance was compatible with the Convention, and in particular with Article 10 (art. 10).