CONTENTS

Policy on Intellectual Property Right (IPR)
Annex 1� Table of Contents
�1���� Introduction
�2���� Location of control points
�3���� Basic and operational maximum usable frequencies
������� 3.1���� Basic maximum usable frequencies
������� 3.2���� E-layer critical frequency (foE)
������� 3.3���� E-layer basic MUF
������� 3.4���� F2-layer characteristics
������� 3.5���� F2-layer basic MUF
����������������� 3.5.1���� Lowest-order mode
����������������� 3.5.2���� Higher-order modes (paths up to 9 000 km)
������� 3.6���� Within the month probability of ionospheric propagation support
������� 3.7���� The path operational MUF
�4���� E-layer maximum screening frequency (fs)
�5���� Median sky-wave field strength
������� 5.1���� Elevation angle
������� 5.2�� ��Paths up to 9 000 km
����������������� 5.2.1���� Modes considered
����������������� 5.2.2���� Field strength determination
������� 5.3���� Paths longer than 7 000 km
����������������� 5.3.1���� Determination of the fM
����������������� 5.3.2���� Determination of the fL
����������������� 5.3.3���� Estimation of the field strength Etl
������� 5.4���� Paths between 7 000 and 9 000 km
�6���� Median available receiver power
�7���� Monthly median signal-to-noise ratio
�8���� Sky-wave field strength, available receiver signal power and signal-to‑noise ratios for other percentages of time
�9���� Lowest usable frequency (LUF)
10���� Basic circuit reliability (BCR)
������ 10.1���� The reliability of analogue modulated systems
������ 10.2���� The reliability of digitally modulated systems, taking account of the time and frequency spreading of the received signal
����������������� 10.2.1���� System parameters
����������������� 10.2.2���� Time delay
����������������� 10.2.3���� Reliability prediction procedure
For path lengths up to 9 000 km:
For path lengths beyond 9 000 km:
������ 10.3 ����Equatorial scattering
Attachment 1 to Annex 1� A model for equatorial scattering of HF signals