Raised aerial 7ft and in the clear

@keithma See your graphs, it’s raining at your house ?

It’s been chucking it down most of the morning but stopped over an hour ago.

It’s strange you have the same loss of signal as me but shifted a few minutes !
Maybe the passage of an UFO over France that went to England :crazy_face::upside_down_face::wink:

Aliens. It’s always aliens.

It looks as though UPS have lost my aerial. Not only that, the bloody coax hasn’t arrived either and that should have been here already.

I’m not having much luck at the moment.

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French post and UPS : same fight !

I also had heavy rain this morning - a very pronounced effect on the graph:

I’m pretty sure that it’s not water ingress because the effect would persist for some time after the rain stopped while everything dried out, but that’s not the case here. Performance is back to normal almost immediately.

The rain seems to have quite a strong blocking effect on long range signals:
image

Rain does affect microwave signals. I’m seeing exactly the same at all three receivers I look after, the MTG one, my main one and the one in my loft. They didn’t all suddenly have water ingress at the same time, especially as one is indoors :smiley:

I thought it had already stopped raining at the time of the dip though. Perhaps I’m wrong.

I don’t remember seeing such a pronounced effect on reception when the antenna was inside, though perhaps I wasn’t looking for it - maybe water actually on the antenna is making a difference.

It might just have been a particularly dense rain shower though.

Oddly, it’s absolutely bucketing down now, complete with thunder and lightning and message count and range appear completely unaffected. It’s playing havoc with aircraft routing though:

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More Holding :slight_smile:

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RF attenuation due to rainfall is negligible at 1 GHz.


RF attenuation due to wet foliage can be significant at the same frequency.
If your antenna has a clear path to the horizon you should see no impact on ADS-B signals. If your antenna’s view is through trees then you might have noticed signal reduction during and after rainfall.
Really heavy local rainfall also drives away airplanes so there really are fewer signals and weaker signals during cloudbursts.

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Later in the day there was more very heavy rain, and I didn’t see the same dip in messages that occurred earlier. There must have been some other cause for the sudden and brief reduction, but I don’t think it was that aircraft were moving out of range. Looking at the playback for the day on planefinder for that time there is no sudden change in the number of aircraft in the air within what would be the normal range.

I don’t have any foliage at antenna height, and have a clear horizon apart from a couple of buildings. The approach paths to the London airports were quite heavily disrupted by the weather with planes holding and routing around it later in the day, but they were all visible and within range.

Whatever caused it was a real effect though, because it was seen across several receivers at a similar time.

I think the message rate did increase fractionally but I lost signals at the limit of my range and the signals that were there were weaker than before (assuming I’ve read the plots correctly). I’ve gone back to 14.
13:

14:

Like Keithma said : aliens, it was always aliens ;+)

Possibly static charge on the raindrops.
This causes a rise in the noise level.
On occasions I have experienced endstop noise at uhf frequencies during extreme rain events.

Could cloud cover, and its density, also be a factor. I have not tracked it ‘scientifically’, but it appears to be the case. I first noticed it with GPS signals.

Move one of my antennas to a pole at 40 feet and am seeing tracks near 230nm which I think is about as far as I’m going to get.

did you check on http://www.heywhatsthat.com/ your max geographic range?
It’s a good comparison if you’re close the the max.

Yeah, in some places I get a little more range and in others not as much as what it shows. It’s pretty close to what is displayed.

Then it’s getting harder to optimize it more.

For me the same, even with my indoor antenna. I am close to the max range i can get for my location.
one of the things which will improve by moving the antenna outside without changing elevation is the number of messages.and the number of aircraft at the same time, but nothing on the range