John,
435.800 is the center frequency. You want that to be 1200 Hz or more above your carrier frequency if you are using USB. Depending on the mode you are using and how your radio adjusts the carrier frequency, vs what it displays, you may be able to set it to .800 or you may need to offset it slightly.
If you can observe a pass, then check what frequency FoxTelem says the data has locked into. 1400 Hz is a good value, meaning the data is 200Hz above DC and extends to 2800Hz. You radio bandwidth should be set wide enough to cope with that.
There is some trial and error here as your radio calibration might vary vs someone else's.
73
Chris