The mystery MFSK32 transmission which has been heard occasionally before and after the VOA Radiogram broadcast Saturdays at 1600-1630 UTC on 17580 kHz was not heard last weekend by any listeners in Europe. It was heard by Mike in Washington state, at about 1542 UTC. The fact that the transmission was heard only on the US west coast introduces some interesting propagational questions about the station’s location. The mystery station also now seems to be transmitting before the North Carolina transmitter signs on at about 1545 UTC with an open carrier. Let me know if you hear and/or decode the transmission this weekend.
Many of us have noticed more hum on the 50+ year old transmitter in North Carolina. The strongest manifestation of the hum within the passband is at 360 Hz. This mixes with the VOA Radiogram MFSK32 signal which, centered on 1500 Hz, extends from about 1250 to 1750 Hz. The “ghosts” above and below the main MFSK32 trace is caused by mixing products: 1250 minus 360 = 890 Hz; 1750 plus 360 = 2110 Hz; and all frequencies between. Roger in Germany provided this illustration:
(all days and times UTC):
Sat 0930-1000 5745 kHz (will change to 5865 kHz starting 6 November)
Sat 1600-1630 17580 kHz
Sun 0230-0300 5745 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.
The Mighty KBC will transmit to North America Sunday 0000-0200 UTC (Saturday 8-10 pm EDT) on 6145 kHz, via Germany. A minute of MFSK32 will be at about 0130 UTC. KBC will also transmit to Europe Sunday, 30 October, at 1200-1300 UTC, on 6095 kHz. A minute of MFSK32 will be at about 1230 UTC. Reports to Eric: firstname.lastname@example.org .