I find the 19KHz analog pilot is substantially less stable than in some competing boxes. It stays within tolerance, but jumps around with modulation more than I like. The HD seems to run just fine. As with all exciters these days, put it on a UPS. If you can find one, I'd do an A - B with the Continental product. Usually the newest one out takes advantage of the latest technology, and addresses the whines about the last one.