On May 5, 2022, at 12:34 PM, Keith <geek4096@...> wrote:


Did you try transmitting into a shielded dummy load? That can often narrow down the RF-in-the-shack issue.

On 5/5/22 15:30, Robert via groups.io wrote:
Hi everyone. My Yaesu FT-991A has stopped transmitting using FT8. I have had this problem a few times but it was always cured by doing a full factory reset of the radio. This time that has not helped. The radio/MacBook Pro is otherwise working fine. The radio transmits normal on HF using SSB and AM. Like I said, I did a full factory reset (and correctly reentered all menu items) and restarted the Mac.

I'm not sure but I suspect it may have something to do with RF in the shack. I'm using a TON of ferrite everywhere and a shielded CAT cable between radio and Mac with more ferrite. My antenna is a Chameleon Lightweight End Fed Sloper. I have never had the slightest problem with RF in the shack with normal SSB phone use. Digital stuff is new to me so I'm not sure if the threshold for RF in the shack is lower. I THINK I have noticed the problem of the radio failing to transmit in FT8 with higher power (100 Watts) vs 5 or 10 Watts which leads me to think it could be RF in the shack although my radio and accessories have never been hot with RF to the touch so it's really just a guess.

I reset the radio and computer and dialed the radio down to 5 Watts and still no transmit so I'm stumped. Any suggestions would be greatly appreciated! BTW, I'm an FT8 (and digital) newb but I have made a number of successful DX contacts on FT8 so the radio and setup WAS working fine. Thanks!

Robert KI5TPC