I happen to find a pair of LEOs running CO K and Ka band. I took the opportunity to do a little testing with the Pro 58. The k band first hit took place at 2 miles. The KA band hit was at 1.5 miles. Both hits were straight line hits. The Pro58 is the same platform as the Pro73 with a couple of less features.
For those of you that want an inexpensive backup detector, the Pro58 is good choice.