I believe Dave is feeding the FT-5000 MP with external audio from the brief station description he gave and apparently the DSP can be adjusted to allow just under 8 kc [probably 3.8 plus 3.8] when running AM. He was driving the Acom 2K with about 10 watts of drive power which would produce a carrier level of about 300 watts. I was looking at the specs for that amp, not that I could afford one, and it's quite a monster in the ratings department. The 3 element STEPPIR would no doubt produce quite a potent signal with the antenna pointed in our direction! We chatted for about 20 minutes without any noticeable fading and when I signed with Dave he was bombarded with calls from across the US. I think he was enjoying the sound of AM and hope he shows up regularly!
By the way, take a look at Dave's QRZ page. Click on the picture in the upper right to see his beautiful estate in the country! I could definitely see myself sipping a cup of tea while sitting in that rear porch before working through a few grueling pileups!http://www.qrz.com/db/m5afd