PC-HFDL Software
PC-HFDL is an
excellent program from Charles Brain that allows you to decode HFDL messages to
from aircraft. It also allows you to view which frequencies are active
around the ground stations of the world. It works almost out of the box
with a line-in from your HF receiver tuned to one of the active frequencies.
In the screenshot on the left below shows the Auckland ground station squitter
signal being received. The closer to zero (0) the value to the right of
FREQ ERR is the closer you are tuned to the correct frequency, a good range to
aim for is 0 - 10. The screenshot on the right below shows an HFDL signal
from a United Arab Emirates flight showing that not even the ground and aircraft
are exactly tuned to the same frequency (and by this I mean in the order of Hz).
I find the values of the FREQ ERR are approximately equal to Hz so this should
give a reasonably good indication as to how well your receiver is calibrated!!
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Thescreenshot below left shows the Squitter window and the frequencies of some of the ground stations. The screenshot below right shows some messages from aircraft communicating with Molokai in Hawaii
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© EazyPC Installations Ltd 2005