On telemetry API: "ValueError: could not convert string to float"

Sentry Issue: SATNOGS-DB-B7

ValueError: could not convert string to float: '39.44W'
  File "db/api/views.py", line 266, in create
    data['lng'] = (-float(lng[:-1]) if ('W' in lng) else float(lng[:-1]))
  File "rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
...
(4 additional frame(s) were not displayed)