11 June 2021

Told Ya' So

A week ago I published a post titled The IC-705 Reassessed, where I pulled back my previous endorsement of the IC-705 due to the often crippling RFI issues. I linked my post to the most active IC-705 Facebook page and, as anyone with experience with Facebook can guess, the flamers and the tolls crept out of the shadows and accused me of everything from exhibiting signs of advanced dementia to criminal-level stupidity when it comes to my ability to investigate and mitigate RFI.

I knew it would happen, and I enjoyed the repartee. 

But I also thought I'd give Icom a chance to respond to the issue, so I sent them a tech support request through their website:

"Dear Icom, I have a problem with RFI over what I suspect is the USB connection that is nearly impossible to mitigate. The issue exists for both the battery charging over USB connection and USB rig control. I've tested with a variety of USB cables, all heavily 'choked' using ferrite cores, and tested with a small group of Windows 10 laptops and tablets. The RFI, particularly on digital modes, overwhelms the rig. The problem exists on 20, 40 & 80 meters, but seems worse on the lower bands. Has Icom worked out any mitigation strategies for this issue?"

Here's the response I got from Icom USA:

Well gee, even Icom admits there's an issue...

I have a lot of confidence that Icom will get this fixed. The IC-705 is a flagship product in Icom's Amateur Radio lineup, and the rig has the potential for a very long (and very profitable) production run, so Icom knows they have to get this right. I think my biggest fear is that the RFI issue isn't one that can be addressed in firmware, and IC-705 owners will have to send their rigs back to Icom for board-level work.

I intend to 'poke' Icom USA on this at regular intervals, so stay tuned.

W8BYH out


  1. Hi Brian | W8BYH,

    I'm Mike | AB6EW and also is a DHS SHARES Radio Operator.

    Brian I have spoken with The Radio Expert Julian White | OH8STN and asked him about your problem.
    Here is what explained to me:

    Survival Tech Nord: This is a well-known issue. If you are charging via USB while using data and cat control over the USB connection, you get rfi on the cable. If you disable USB charging, there's no or if I hash at all. I mentioned this in my initial review of the radio.

    Julian operates strictly wireless, this just might solve the problem?

    Hopefully you should be able to get the wireless operating with your Toughbook Laptop!

    Let me know should this information might be of value!

  2. I also have the noise issue with my IC-705. I tried turning off charging over the USB cable, with no success. I really like the radio. However I wish I would have found these discussions about this issue before purchasing it, as I would have waited until the issue is fixed. The noise is so bad it renders my 705 useless for digital modes. An interesting side note is that a friend of mine purchased an IC-705 at the same time and his does NOT have the problem. With my setup I have unusable noise levels, and all I have to do is unplug my radio and plug in my friends radio and there is no noise on his radio. So the only thing that changed is the radio. Go figure.