HF Data Communications

In this part we take a look at where data communications using HF, or Shortwave, might fit into emergency communications.  We will examine the issues around antennas and propagation, and the multitude of software packages you might use and modes that you might encounter on air.

Part 3 - HF Data Modes

NVIS Experiments on 5MHz from Barmby Tidal Barrier

A communications test on the 5 MHz band was carried out this evening by members of the East Yorkshire Emergency Communications Group from the Barmby Tidal Barrier (NGR SE 681286), using a wire dipole antenna setup for Near Vertical Incidence Skywave.  A propagation mode where the radiated energy is directed vertically upwards by installing the antenna low to the ground, and relying upon the ionosphere to reflect the signal back down to earth - giving a range of approximately 200 miles.

Strong CW signals were heard on 5258.5 kHz, the propagation beacons GB3RAL, GB3WES and GB3ORK were easily audible on 5288.5 kHz above the QRM, and several stations were active higher up the band at approximately 19:30z as the sun was starting to set.