Remote HF Radio Control Via the Internet
Antenna Control

Antenna Control is accomplished using several external hardware devices coupled with internal features of the control software. A relay board with 8 relays is connected to the server computer via a COM port.

The relays on the board are used to drive a WX0B Six Pack, a remote coax switch for switching six antennas. In the current configuration at KH7R, we are using individual antennas (and stacks of yagis) for 6,10,15,20,40,80 and 160 meters and a log periodic antenna for 12,17 and 30 meters.

Antennas that are automatically switched include:

6 ELE 6 meter yagi and 5 ELE 10 meter yagi (rotatable) at 90 feet.

8 over 8 over 8 on 15 meters, 2 fixed on North America, one on Japan.

5 over 5 over 5 on 20 meters, 2 fixed on North America, one on Japan.

3 ELE yagi on 40 meters, fixed on North America at 90 feet.

80 meter dipole at 120 feet.

1/4 wave vertical on 160 meters.

Log periodic at 90 feet for 12, 17, and 30 meters fixed on North America.

By using a diplexer (six meters/HF), an additional coax relay, and the two antenna ports on the FT-920, all the antennas are automatically selected based on the frequency the radio is currently on. The operator can manually choose between the rotatable six meter antenna and another fixed six meter yagi.

The server software, which is constantly monitoring the radio, selects the antenna based on the frequency of the active VFO on the radio. Antenna selection is user configurable in the server software, and allows any possible combination of antenna selection for all the HF bands, including using the same antenna on multiple bands (tribanders, log periodics, etc.). Server software control of antennas was chosen as it provides more flexablity and reliability than the use of external 'band switching' devices. The operator can easily configure frequency ranges and choice of antennas while the radio server is running.

On the user end, HF antenna selection is transparent - it is all done automatically. For six meters, the user can select the second (B antenna) port on the radio itself. Multiple six meter antennas can be selected using the AUX relay function of the software or by using the unused two relays on the relay board, by switching coaxial relays.

Rotor Control of Hygain Tailtwister rotors is accomplished by using the Idiom Press RotorEZ controller with the RS232 interface option.

The interface is fitted internally in the rotor controller, and a COM port on the server computer is used to control it. The radio server software relays bearing information back to the user program so the user is constantly aware of the bearing of the rotor(s).

On the user end, control of the rotor(s) is very simple. The user can configure and name 12 rotor preset bearings:

After these presets are configured, rotors can then be controlled by clicking the appropriate rotor on the display screen, and using a simple interface to turn the rotor:

The user may enter any desired bearing (0 - 359 degrees) or simply click a preset, which will send the selected rotor to the bearing that was configured for that preset.