The bigger part of this is your transceiver. A 100W PEP radio will get very very hot using these digital modes. (Almost like continuous duty) And you can shorten it's life.
Well, if the radio IS RATED for %100 Duty Cycle
I don't see a problem. I've run %100 Duty Cycle radios
at 100+ watts on FSK or AFSK for 12 hours straight, and
40 out of 48 hours in contests.
That doesn't mean I endorse 100w, on PSK31,
but I have run it occasionally.
Speaking of shortened life......I recently got an LDG Z-100PLUS ATU
This is the
exact quote from the included manual:
SPECIFICATIONS:"0.1 to 125 watts SSB, CW, and digital modes."
This is the EXACT QUOTE from the LDG Website
for the Z-100PLUS ATU:
Specifications:"RF Power: 0.1 to 125 watts SSB and CW, 30W on PSK."
Check it out before they change their claims:
http://www.ldgelectronics.com/c/252/products/17/49/2