I agree with other posts, if your external tuner will handle the power and
it will tune the antenna, the amp should be fine. For a similar reason I
run an mfj 898 here for an external tuner. BTW, you can read swr with
your 590. I have found some times it agrees with the tw1, and sometimes
not.
73
Butch
WA0VJR
Node 3148
Wallace, ks.