Once my SignaLink was installed I downloaded and installed Easy Pal, which uses DRM (Digital Radio Mondiale) encoding to allow the sending of image or text files over HF. After the program was installed and configured, I connected the SignaLink to my HF radio into a dummy load and pressed the "Tune" button. I monitored my transmit frequency on a second receiver and heard beautiful digital sounds. I was on the air! "That was easy", I thought, but I was just starting my journey. There are several lessons I learned while using Easy Pal (and I'm still learning).
- My radio's reference oscillator was off frequency enough that I could transmit pictures, but my signal was not optimal. It was necessary to open the radio and adjust the reference oscillator. The last time I checked my radio was only 4Hz off, well within tolerance.
- I had the RX Level turned up WAY too far and had trouble receiving images. It was necessary to adjust the level so that the "RX" bar (below the receiving station's callsign) was within the AGC range (not more than the small bar within the "RX" bar). Once it was adjusted properly, I received most stations well.
- The digital port on my radio had been maladjusted (cranked up all the way by a previous owner?) and my transmit signal was too hot. It was necessary to open the radio and adjust the digital port input for minimal ALC. I later set the SignaLink front panel controls so that the TX level and Delay controls match the optimal RX level, then readjusted the radio digital control for minimal ALC so that all knobs on the SignaLink are in the same position. I can now tell at a glance if the knobs are correct. In also verified that my other digital programs do not move the ALC with the same SignaLink TX level control setting.
Available from http://www.kc1cs.com/digi.htm