The ionospheric critical frequency (foF2) and the F2 layer height (h'F2) variation over Kupang during 2014 period unchanged varied where it is dependent on solar activity, the higher the level of solar activity the higher the level of variation in foF2 and h'F2, conversely the lower level of sun activity diminishing the level of variation foF2 and h'F2 variation changes to the F layer is indicated by a decrease and an increase in the value of foF2 and h'F2. Increasing the value of the average foF2 occurred at 07:00 pm reaching it's maximum at noon and 12:00 to 14:00 pm followed by impairment foF2 at night, which reached it's minimum at morning 5:00 to 6:00 pm. During 2014, the altitude of the F2 has three patterns different upgrade, (1) an increase in height on the hour midday as happened in January-April, (2) an increase in the hours of midnight until before sunrise, hours noon and afternoon until the evening occurred in May-August (3) an increase in the hours of midnight until near sunrise and midday hours as in September-December. In the media utilization as reflected waves of high frequency radio communications (HF), characteristics of the ionosphere above Kupang during 2014, has the ability to reflect high frequency waves that are in the range of 2 - 19.2 MHz with a height that is in the range 179-550 Km. Will lead to high frequency radio communication failure, when using a frequency of greater or smaller than the frequency that can work. Keywords: solar activity, the critical frequency of F2, F2 layer heights, radio communications, high frequency.