So Madonna is/was a dasher beacon in the Inyo mountains area and sun only. The Marin Ditter is AC line powered in the attic of an apartment building
Thanks for that Teotwaki.
I have not been actively listening out for HF beacons for long, so cannot tell the difference between some of these "legacy" beacons by listening to them, otherwise I might recognize subtle differences in the speed of the ditting, or even the sound of the keying waveform. I heard what I think was Madonna during daylight hours so, by that metric, it could have been either beacon. However, the beacon I heard was on 4097.27, which is only 40hz from the frequency that MB reported Madonna as being on. For it to be the Marin Ditter, it would have had to have drifted 420Hz from it's earlier reported frequency. Though not impossible, it's quite a lot, for what I assume is a crystal-controlled oscillator - even if there's a fair amount of inductance and/or capacitance in series with the crystal (unless the frequency was altered by human intervention).