Adventures in radio - April 2023

2023-03-29 ICOM IC-705 Problem and troubleshooting


The mic issue was resolved but everything was still not quite back to normal as SWR was ridiculous (at times greater the 4:1). The other change I had made was to add an MFJ-949E Deluxe Versa Tuner II Antenna Tuner (picked up used at an RCARC club meeting) on the desk and connecting it to the IC-705. I had been running it in BYPASS as I was using this primarily as a switch for the 2M antenna, with the MFJ 949E replacing the coax switch that was there before. I should have read the insructions but in my poor defense there wasn't any. I did look at I think it was the DX engineering site which said up front "handles 300 watt RF output power and will match any transmitter or transceiver to virtually any antenna."

You probably see where IM going with this. That tuner was rated for 160M through 10M so a 2M antenna even in BYPASS was just not going to work. Solution? Remove the antenna from the tuner- run it back into the coax switch and then into the IC-705 - pretty much the configuration I had before all of the changes. SO problem solved now? No… the SWR on the 2M Ed Fong dipole antenna was still ridiculously high. What gives? I’ve been running this antenna indoors, in the same location for 2 years now. Turns out the antenna was hooked across a window blind and at some time the blind rolled up more than usual and the antenna was now stuck in between the window blind and the window frame which is apparently the absolutely worst place for it in the entire room (apparently even just laying the antenna on the floor brough the SWR down to just under 3:1 instead of the nearly 5:1 that I was seeing. I think the window frame is aluminum and that was what pushed the SWR to its level as the antenna was literally squeezed against the aluminum frame. Finally problem appears solved.






It's almost the end of the month, and I haven't written anything before this. I have one new project, my first permanent antenna setup, but that will have to wait for next month. I DO want to give a shout-out to Julio, W4HY for a rapid response to my call for help on the ICOM forum. I had tried everything I could think of, but while I could see that I was transmitting on 2M, nada was heard when listening on any of my HTs. When I transmitted from the HTs, I could hear myself clearly on the IC-705. Julio suggested to:
"Check your MENU>SET>CONNECTORS>MOD input settings. It should say MIC or MIC, USB in the selection. This sometimes doesn’t get put back to MIC when doing the Data modes.".
I thought that I had checked this off before, but guess what? That was exactly the problem. Again thanks, Julio.





'73 from KD2WLL - the adventure continues