On Sunday, December 31, 2017 at 3:13:42 PM UTC-7, Dan Marotta wrote:
If it's not too much trouble, try a coax cable length of 21 11/16 inches
which would be 2 wavelengths at 1090 MHz (assuming my arithmetic is
correct).Â* You may have reflected power in your coax which will reduce
performance.

Dan: I'm not jumping into the real technical matters here but its pretty obvious that you're neglecting the fact that waves travel slower in coax.