472kHz - an analysis of EA5DOM with and without RX preamp

The night before last EA5DOM (1525km) was copied 45 times on 472kHz with the preamp in circuit, so the FT817 was at maximum sensitivity. My best report of him was -16dB S/N.

Last night he was copied again but without the preamp. Last night I copied him 35 times with a best sensitivity of -19dB S/N.

Although conditions may have been different, I think the 472kHz preamp is worth having. It allows signals too weak to copy to be successfully decoded. Incidentally, EA5DOM was copied as late as 0740z today at -26dB S/N without the preamp on 472kHz WSPR.