Hi Doppler shift depends on where you are (on earth) relative to the satellite. A radio cannot know this, also not a TS2000. This is what software like satpc32 is used for. What a TS2000 and some other radios can do is apply a fixed ratio between uplink and downlink of a transponder. Excluding doppler. Btw also excluding eg a freq shift (drift) during a pass like AO73 has. That is something also satpc32 cannot compensate for. Enjoy the challenge! Henk PA3GUO <I thought the TS-2000 had all the doppler correction built in. Why aren't you using that since your laptop isn't attached to the radio????