Is a Hammer Switch needed for good data quality?

If you are doing refraction and reflection then the trigger timing accuracy is important - especially when trying to get high resolution imaging.

For MASW the trigger timing accuracy is less important because the frequencies of interest are lower and the analysis method only relies on the phase differences of the signals between geophones and not the absolute time between shot event and the signal received on the geophone.

If you are acquiring individual records for each hammer blow and then inputting them into Pickwin, then a hammer trigger is not required, you can use an auto trigger method for the Geode. If you are stacking the data in the Geode, then a hammer trigger will be required.