Conditions are good on VHF and I just loaded my map to see this! I don’t think I’ve ever seen so many aircraft on the map.
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It’s exactly that, tropospheric ducting. I’ve been listening to a couple of Belgian radio amateurs driving around near Ypres with half wave aerials on their cars, simplex on 145MHz and there are plenty of Dutch, French and a few Germans on as well.
It won’t just be me seeing this increase in aircraft, I expect the conditions are covering a large area and this is very impressive, I’ve not seen an opening like this for many years.
I love radio, it’s so unpredictable.
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That’s crazy. Interesting that the Martello tower receiver doesn’t seem to have the same increase even though it’s quite close to you. I’m not seeing an increase like that either.
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I suppose the closer the inversion layer is to the antenna, the more noticeable the effect?
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Actually, you’re right, this does appear to be relatively local.
Look at the huge number of ‘others’ today (actually, conditions were good yesterday as well and the ‘other’ figure was well over double what it normally is).
@caius, you’re seeing more than yesterday but not to the same extent as me.
My friend Tony is roughly central between me and the MTG is also seeing a big increase in ‘other’ today. He’s using an RTL-SDR dongle and a Pi3.
And so is this one - I don’t know exactly where he is but he’s somewhere relatively local to me.
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Yes, looking at my stats there is an increase over recent days, and I am definitely seeing an increase in range today:
Probably your antenna height and clear horizon means you get a much bigger benefit from the ducting effect.
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Conditions on VHF/UHF are still really good, I just spoke to a friend in Wales who was in his car on 433MHz.
The number of aircraft tracked and tracks seen has dropped down since earlier today but look at my range.
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You should modify your max-range setting in your dump1090-fa config, the default is 360 nmi.
Also you are receiving a Denmark coastal ground sation, a whopping 330 nmi away!
@keithma Could you maybe stop showing off now? 
You are making the rest of us look bad.
I’m also gettting some ducting it seems:
Ground target at 205nm.
I’m tracking a helicopter up over Denmark at just over 1,000 ft. I picked him up at around 800ft AGL at 360nm out.
I’m lost for words, again, this is why I love radio.
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When I still had a beam up for 2m, the first site I opened every day during the summer was the Hepburns to see if there was a chance of tropo. Didn’t even think of that today.
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It’s a useful site. I usually take a peek every day, this strange weather we have right now (+8C and strong winds, usually we have -5 - -10C and lots of snow) can surprise with some really good conditions.
Had a good run yesterday, almost like summertime stats.
@keithma Have a look at the range/altitude plot for your receiver:
You can really see the effect of the ducting - you could see right down to the ground for so many airports, no wonder you had so many aircraft in view. Interesting that there’s a kind of hole around 105-139 miles away.
You might want to re-run the graphs increasing the range a bit - the one at the top of the script does the maps, but the altitude graph is set further down - line 487 will change it.
In comparison, I don’t see the same over the horizon effect:
Really interesting to see how comprehensive the reception you got was.
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Done
Any idea why is the map truncated? If you look at the very last plot, the map doesn’t go to the edge, even after I forced a new download of the world_10m.txt file.
I’d quite like to see that map go all the way to the edge - At the top right. there’s a trace that looks like a greater than > sign. That’s a helicopter making two journeys at a maximum of 1150ft and around 380nm away.
That’s an oversight on my part - I limited the map file to 350nm from the receiver to keep the size down. There didn’t seem much point in plotting the entire globe if only a small part is visible on the plot. I didn’t anticipate needing it to be larger than that,
If you look at line 348, you can change that to something large enough to cover the range you are plotting. Then delete the world_10m.txt file to regenerate a new one.
I’ll update the script on GitHub tomorrow to make the default larger.
Done and it’s regenerating now, thanks.
Why were you up at that time of the morning? I’ve got a good excuse in that I’m only able to catnap due to my arm. Most people should be asleep at 03:00! 