Listening to the birds..

Well, the title maybe not that correct when it´s actually airplanes that I´m referring to. 🙂

That aircrafts can communicate with the ground via VHF radio is, as I belevie, a common knowledge among those interested in air band listening. The downside with VHF is that it has a quite short range when it comes to flying over oceans and land with small infrastructure capabilities. For example the flights from Europe to North America is one of the areas where coverage of the entire flight leg is hard to achieve. This is were HF communications comes in.

With the use of HF frequencies long range communication can be achived and the oceanic areas can be covered by a handfull of land stations.
To listen to the aircrafts is quite easy when they in general use SSB modulation (USB) along with SELCALL equipment. From my part of the world, in Europe, there´s the NAT (North Atlantic) area frequencies to listen to. These frequencies are used by aircraft’s traveling between Europe and North America and also thoose heading for the North Atlantic Islands.

There is a number of frequencies used the most activity, in my experience, is mainly from those covering the NAT Family A, B, C and F. The land stations covering the frequencies are mainly Shanwick Radio (located in Scotland) Gander Radio (located in Gander Canada) and New York Radio (located in New York). Below I´ve listed the different NAT family frequencies and also a map showing the correspondent areas.

areas

NAT Family  Frequencies

A                  3016, 5598, 8906, 13306 and 17946 kHz
B                  2899, 5616, 8864, 13291 and 17946 kHz
C                  2872, 5649, 8879, 11336, 13306 and 17946 kHz
D                  2971, 4675, 8891, 11279, 13291 and 17946 kHz
E                  2962, 6628, 8825, 11309, 13354 and 17946 kHz
F                  3476, 6622, 8831, 13291 and 17946 kHz
H                  3491, 6667

Because of the lack of RADAR coverage over the Atlantic, aircrafts are required to report there position in a certain time interval to the Air traffic control (ATC). This generates quite a lot of communication during popular traffic hours.

Tomorrow I´ll return with more tips regarding Aeronautical HF communication and why weather reports can be a useful tool not only predicting what to wear.. 🙂

73 de SM7VRZ

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