Thanks for both your comments!
MikeMI, I did wonder this myself. I know I am just inside the "frequency range" but understand it is advisable to go much higher. If I were to run multiple tests, couldn't I increase the accuracy of my results by using an average?
Antknee, thanks for the link. I read a few similar posts and (like u, I presume) would spend more if I could, but am working with a limited budget. What sort of baud rates/frequencies do you work with? Anything as high as 9600?
Thanks
Gary