Impact of atmospheric/weather conditions on range


#1

I have noticed the number of long range hits I get (400km+) seems to vary quite a bit day to day, some days I can get hundreds, other days maybe only 20 or so.

Does weather (mainly cloud cover) and/or atmospheric conditions impact this at all?

I know some of the higher frequency signals such as around the 2.4Ghz/Microwave can be impacted by moisture in the air, not so sure about 1090Mhz.


Unusual, extraordinary, and momentary signal propagation
#2

I believe that it does. I’ve noticed that when there are thunderstorms 600+ kilometers away, I will frequently receive signals from flights at otherwise-impossibly-low (11000 ft) altitudes in the 500-550km range. It’s almost as if the signal is bouncing off either the moisture in the air or the charged particles or something like that.

Similarly, I’ve noticed that when there are thunderstorms closer to home, along with high humidity levels, I’ll get more of the brief, long distance blips appearing. I’m open to other explanations, but weather can nditions seem to be a common factor.


#3

Maybe retransmitted data requested by aircraft that can’t see it due to thunderstorms? Do you have reception from one or more ground stations?


#4

Not that I’m aware of. Is there a way that I could recognize reception from a ground station? I’m receiving only 1090mhz (no 978mhz) and no MLAT.


#5

I have some experience with rf propagation at uhf and microwave. Maybe you can soak a little out of this webpage:

mike-willis.com/Tutorial/PF6.htm

Must admit I did not totally read it but on skimming it looks good.


#6

Please see this thread also:

Radio Wave Propagation - VHF, UHF & SHF


#7

I have seen this mentioned before as well

amateur-radio-wiki.net/index … ic_ducting