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E Skip vs. Tropo Signal Variation And Cool Signal indicators

S

Schroedingers Cat

On a d'Arsonval movement S meter with fairly linear signal indication, Tropo is fairly steady to slowly varying over several tens of seconds to several minutes and Sporadic E will have several signal variations per second, like shortwave but a lot faster. Magic eye signal indicators will also show these variations better. The signal variations shown by these tubes is typical of shortwave in the 10 to 15 MHz range. FM Sporadic E would typically be much faster, and FM tropo much slower.

http://magiceyetubes.com/patterns.htm
 
If you have pictures or videos of other signal meters, feel free to post links. Also, if you have video of signal meters with AM skywaves, Sporadic E, or other DX, we would like to see them. If you have AM skywaves of other broadcast signals actually measured by calibrated field strength meters, we would like to see them. Receiver location and station information would be useful.

Logarithmic response to signal strength in meters is less dramatic and diagnostic of signal path.
 
Signals received by sporadic-E very often do have rapid fading patterns visible with an S-meter or magic eye tube, but I've also had sporadic-E reception that has been rock-steady for as long as half an hour.
 
I had an e-skip once where the station came in more like it would in tropo - with little variance in signal strength for a good 20 minutes. I was getting 98.3 KATR from Otis, CO here in Vermilion, OH. It was after dark here around 10pm so maybe that had something to do with it.
 
I've seen E-skip DBUs up in the high 20s and low 30s. Mainly it's in the mid teens DBU.

-crainbebo
 
The dBu level will be dependent on the antenna system, and will vary from one receiver to another, and S meters are notoriously inaccurate without a near professional calibration to a real field strength meter done at various frequencies across the band. But some graphs in the NAB Engineering Handbook indicate signals at 1000 miles that peak close to inverse field. A 100 kW ERP station has an inverse field of 1380 mV/m at one mile, so you could have a signal in excess of 1 mV/m at times 1000 miles away. I have seen some that came close to nearby 2 mV/m F(50,50) signals in the S meter deflection. But they almost always varied quite a bit, and irregularly, not a simple fade out and fade in but with some fades less than others.
 
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