Publication: Magyar Közlöny
Issue: MK-2007-70 (Year: 2007, Number: 70)
Era: 2004-2010
Section: Melléklet a 2007. évi XLVI. törvényhez
Paragraph Index: 3713

b) at least once a month for non-crystal controlled transmitters. 6.6.1.1.3 If practicable, tests at shorter intervals should be made. ATT C-67 23/11/06 2007/70/II. szám Annex 10 — Aeronautical Communications Volume I 23/11/06 ATT C-68 6.6.1.2 Frequency of the modulating tone 6.6.1.2.1 The identification frequency requirements are specified in Chapter 3, 3.4.5.4. An audio signal generator calibrated to an accuracy of 0.5 per cent or better at the specified frequency is recommended as a calibration standard. 6.6.1.2.2 This test should be made at least once a month. 6.6.1.3 Ground wave field strength 6.6.1.3.1 It is recommended that remote field strength measurements be made using a field strength indicator set capable of checking that the power radiated from an NDB is in accordance with Chapter 3, 3.4.3. 6.6.1.3.2 This test should be carried out at least once a month. 6.6.1.4 Modulation depth 6.6.1.4.1 Chapter 3, 3.4.6.2, requires that the depth of modulation of the carrier frequency should be maintained as near to 95 per cent as practicable. Use of an oscilloscope capable of operation at the transmitting frequency of the NDB is recommended for this purpose. 6.6.1.4.2 This test, using an oscilloscope, should be made at least every three months. Additionally, rough checks of modulation depth may be made frequently by using a calibrated diodevoltmeter, but these are not a satisfactory substitute for the test using the oscilloscope. 6.6.1.4.3 Unwanted audio frequency modulation should be measured at least every three months to ensure that it does not exceed the limits of Chapter 3, 3.4.6.5. An oscilloscope is also recommended for this test. 6.6.1.5 Fall of carrier power with modulation 6.6.1.5.1 When modulation is applied, the carrier power should not decrease by more than the amount specified in Chapter 3, 3.4.6.4. A recommended method of ensuring this is to use, at a suitable remote site, a calibrated communication receiver having a continuous wave IF crystal filter as an indicator of transmitter field strength and having sufficient selectivity to reject the audio sidebands. 6.6.1.5.2 An alternative but probably less accurate method of determining the fall of carrier power would be a comparison of the current fed into the antenna when the transmitter is modulated with that when it is not modulated. 6.6.1.5.3 This test should be done at least once a month.

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