VLR Skerryvore · 56.4°N 6.4°W · 1.8–16 MHz
3.002MHz
- Signal
- S0 · noise
- Detune
- —
- Ceiling
- 3.40
- Passing
- CW
23:10
band open
dawn 05:05
A vessel is working distress somewhere on this band.
Copy sheet
Tune to a carrier and hold COPY to read it.
Log sheet
VLR Skerryvore · 56.4°N 6.4°W · night watch
Shortwave
A vessel is calling distress 1 446 km north-west of you, on the worst night of the season. Tune the band, copy her burst transmission character for character, and pass it to the coast station on 2182 before the low bands close at dawn.
- Tune
- ← → or A D, sweep while held. Shift for the 1 kHz vernier.
- Copy
- Hold Space, or hold Copy. Ride the fading; uncertain groups will not lock.
- Relay
- Take the copy to 2182 and answer GKZ. Escape pauses, M mutes, H opens this.
The ceiling is real: foF for 14 May, a smoothed sunspot number of 95, an obliquity factor for the hop, and a storm-time D layer over the North Atlantic.
Reference
How the band works
- Ceiling (MUF)
- foF divided by the obliquity factor for the hop length. Anything above it cannot arrive at all, however loud it looks on the panadapter.
- Absorption
- Appleton's non-deviative term, plus a night floor that rises as 1/f². The low bands go first, which is why the ship is down at 2492 when 3002 closes.
- Greyline
- Where the path midpoint sits at twilight the ionosphere tilts: the ceiling rises and the absorption drops. The best window of the night.
- Blackspot
- A hole in the F2 layer over the pole, drifting south. It takes the high-latitude path first and spares the coast station to the south.
- Fading
- Broad flutter you can only wait out, and narrow notches tied to the ceiling that the vernier can trim around. The carrier also sits a kilohertz above its logged frequency.
- Burst format
- PHRASE, ID, ROUTINE, INFORMATION, then B0 and the B1 check figure — the exclusive-or of every digit in the message with a zero on the left.
Receiver on standby
Paused
The night is held where it is.
05:05 · the band closed