Signal Strength Plot The Crystal Ship 9 Dec 2015 Transmission

[ChrisSmolinski]

Here's a plot of the signal strength of the TCS transmission from last night. I used a narrow (500 Hz) filter on my SDR playback app to capture just the carrier strength. The Y axis is annotated with equivalent S units.

2250 UTC is when the path "went long" and the signal strength dropped. As almost always occurs when this happens:
1. There is a peak in signal strength just prior
2. The drop in strength is quick and dramatic

What's interesting is the little dip in signal strength around 2308 UTC. I'm not sure if I have observed that before, but I'm also not sure I've looked for it.  Other than that dip, the signal was a fairly constant S6. Background noise with this narrow filter was just under S4, with a wider filter as you would normally use, it would be higher. I checked the audio, and other than the period around 2308 UTC, it was weak but certainly listenable, I would give it an SIO 222. Around 2308 was certainly SIO 111 at best.

[John Poet]

Very interesting.  With the trend in MUF numbers I might have expected you to lose this entirely before the end, but you didn't last night.

Using http://www.hfunderground.com/propagation/ tables for Alpena MI,  the calculator says the skip zone would have been somewhere between 300 miles to around 451 miles at the end of the broadcast around 0000 UTC.  Distance calculators put you just about exactly at that 451 mile mark...  (that's a great toy, BTW)

These are some crazy large skip-zone numbers for the first hour after dark on 43 meters...