I have an idea (from my experience using HamAlert): it would be extremely convenient for the DX Cluster interface to have a filter that displays spots sent from within a specified radius of the station's current location.

How to implement it: based on the spotter's callsign, their gridsquare is requested (from the wavelog or callbook database). Then, the distance to the station's gridsquare location is calculated. If it is less than the value specified in the filter parameters, the spot is displayed.

It's clear that this will add load to the wavelog engine, but it would become a unique feature.

And it would allow using DX Cluster much more efficiently. Currently, in HamAlert, you can specify the spotter's DXCC as a limiting filter, but that's a rather coarse filter.