Frequency Skips and Sporadically Tunes Down the Band

Problem: The MP would sporadically start tuning down the band. It didn't always do it, but it would sometimes. Some front panel settings would affect its tuning down; using the Notch filter in conjunction with the EDSP would almost always cause the down tuning. It only tuned down, however, when in SSB mode.

Solution: It appears that Heil wired the cable adapter for the Yaesu radios incorrectly. The Heil adapter ties the Mike Ground and the DC ground together and connects them to pin 5, while the pinout diagrams on page 4 of the MP manual shows that Mike ground goes to pin 7 and DC ground to pin 5. I rewired the plug per the page 4 diagram, and the radio no longer tunes down the band by itself. Why did it not tune down in CW mode? When in CW mode, I always pull out the Heil adapter cable, to get it out of the way. Why notch and EDSP? I haven't figured that out, but my theory is, by letting that signal return float, some kind of circulating current was being interpreted by the radio as an instruction to "tune down"- as though the button on the mike was being pushed. I originally thought it might be a short in the cable, telling the radio to tune down, but there was nothing to short that was connected to either pins 1 or 3. What I can tell you is, since I rewired the cable, it hasn't tuned down on its own. Dennis NB1B




This site was last updated 08/27/07