Download and install these files
For those using FLdigi for the first time, or have had problems with others copying your messages it is strongly suggested you first run CheckSR. Every sound card will produce the same frequency, say 1 KHz, at a slightly different frequency. CheckSR detects these differences and helps FLdigi adjust to these differences.
With your sound card enabled (and Signalink or equivalent connected and on) run CheckSR for at least an hour. By that time the values in the Difference ppm should be changing within a small range. At this point hit the Stop button. You will now have two values, Difference PPM for Input and Output.
Close this window and click on the Save Config.
CAUTION: I suspect this program may do more harm than good on some PC's. I have found that if the results vary significantly from 0, say greater than +-100 ppm, that using the results may make FLdigi unusable. If you find you are having difficulty copying other stations, or other stations copying you, change the corrections to 0 and try your transmissions or receptions again. If you are unable to check FLdigi with the new settings leave them at 0 until you have an opportunity to check them.