I have downloaded your last three files (full CSV). All records have the value GSM in the radio column.
When we read your documentation (https://ichnaea.readthedocs.io/en/latest/import_export.html) it is mentioned that a record can have GSM, UMTS (for WCMDA networks), or LTE value in this column.
Is this field set to GSM by default or is this an error?
Thank you for your clarification.