I currently can run AM on my Icom 7600----I am concerned about it's duty cycle. So I am looking for suggestions on a transceiver which is designed for AM use only.
I generally run all the HF bands.
There aren't really any modern rigs designed for AM only. There just is not a big enough market to warrant such a development. That does not really matter much though, as many modern rigs have quite decent AM operation.
I use my FTdx-5000 and my Flex-5000a for AM on the HF bands quite a bit, my FT-2000 a little also. Both of the 5000's get good reports, and I often listen to my signal on remote receivers. All three of them did require custom configuration to get the most out of AM operation, but that was not really difficult, just had to work around the right menus and settings. I imagine many decent modern radios could be set up similar.
As prcguy indicated, duty cycle is probably not an issue. A radio rated at continuous 100% duty cycle and 100 Watts will do a 25 Watt carrier, 100% modulation, signal all day long. And how long do you key down for? Yes, I know AM roundtables can get long winded, but I have a hard time keeping the key mashed for 3 or 4 straight minutes, not much longer than some SSTV transmissions. And then you are unkeyed for however long it takes to get back around to you.
I can say I have never had an issue with any of the rigs I currently use.
T!