Contact by Radio
The following applet provides a formal way for you to communicate with the named person by radio. This is assuming, of course, that both you and the named person have the necessary radio equipment under computer control.
Retrieve the name & address of the person with whom you wish to communicate. His radio station details will then be displayed automatically in the above applet's window. Alternatively, if you know his station name or call sign, enter either or both above and click the Find button. The rest of his radio data then appears in the applet's windows.
If you are going to use HF, check the current optimum working frequency [FOT] for the radio path between your two stations. Then from his scanning list in the window on the right of the applet, click on the frequency which is at or immediately below the current FOT. If your friend transmits an ident on his listening frequencies, press the Scan button. The applet then causes all these frequencies to be scanned to establish which one provides the strongest signal. Each frequency is highlighted as it is scanned.
When the best frequency has been found, you are ready to communicate. If you are making a voice call, simply use your transceiver as normal. If you are sending data, go now to the file transfer applet.
Fine Tuning Facility
If there is interference on the channel and you would like to fine-tune your frequency, press the Tune button. This causes focus to be passed to the applet below:
This gives you a live view of the radio spectrum roughly 100 kHz each side of your selected communication frequency. The colour of the trace indicates which kinds of station are officially permitted to use that part of the band. The narrow white rectangle indicates the pass band over which your receiver is currently accepting RF energy. The width of the passband is shown as a number of hertz in the passband field towards the left of the applet panel. You may widen or narrow the passband using the buttons beneath the passband field. The centre-frequency to which your transceiver is currently tuned is shown in the frequency field. You may 'inch' this up or down using the buttons below this field. The transmission mode shown in the mode field is initially the one specified in your friend's station data. You may override this by clicking the down-arrow at the left of the mode field and then selecting the mode you want.
The Lock button causes your receiver's phase locked loop PLL mechanism to lock on to your friend's signal. If the channel you are using starts to deteriorate, click the Scan button to reinitiate scanning of the full range of your friend's listening frequencies until the new best frequency is found. You can then adjust the bandwidth and centre frequency again if necessary. The Data button returns focus to the first applet above.
The above panels are simply images. When implemented as applets, the operation of each button is displayed on the browser's status bar when the mouse pointer is over the button concerned.
© July 1998 Robert John Morton