Traffic Increase

Hi Folks,

No query here, merely an observation.

I live around 12 miles from London Heathrow, lot of aircraft pass overhead into and out of Heathrow. I have a Pi Zero running an indoor setup with standard aerial in an upstairs bedroom by a West facing window.

Normally my daily aircraft count was in the 1700s but has been climbing, appreciate summer here but yesterday my stats showed 2000+ for Friday 8th June. Previous three Fridays were in 1900s and busier than other weekdays but yesterday surpassed all.

Been running consistently for over a year now and still find it fascinating - even took it to California on holiday few months back, that was interesting.



I saw an increase here as well. Thursday is usually the busiest day of the week in my area.


Must be the Summer months.

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I wonder if cloud cover is a factor as well. We had some very cloudy days early this week, and the number of planes seen dropped substantially. Over here, and I guess in the UK too, the number of cloudy days increase in the winter months.

My all time records, for both planes and messages, happened in the summer months.

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A lot must depend on the aerial used, mine is just the supplied antenna.

May try a portable device in the garden but then aerial will be at ground level. Realistically I am only interested in local traffic as I can see planes heading to and from Heathrow, soon as they drop to around 2000 feet approaching Heathrow I lose them.


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In the microwave range, cloud cover and humidity are factors. ADS-B is in the lower end of the range, not sure how much that would impact it.

When a compromise antenna and/or installation is/are used, the extra attenuation could be the proverbial last straw to break the camel’s back.


I live relatively close to an airport, and my numbers have increased, too. Some of it will be holiday travel, and recovering from AirBerlin going out of business might have had an effect, I guess.

I stayed in a hotel close to LHR once, there really is a lot of air traffic, and a lot of it bigger intercontinental planes…

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I just experienced a tremendous traffic ‘increase’. All it took was loosening up the N plug going to the FA antenna. I’ve not checked the innards of the antenna, but looks like tightening the plug too hard - a bad practice of mine, I’ll admit - causes a problem.

My ‘deluxe’ setup was ‘performing’ pretty much the same as my ‘poor man’s’ setup. Not a normal thing to expect.

Let’s see how long it’s going to be this way. If the performance drops again, I’ll have to open the antenna to check for bad/broken connection.


yes it appears to be strange, but the small gap between the center pins
is doing it. I was puzzled by the same effect.
Then I remembered the DIY filters been tuned by ‘adjusting the gap’.
I asked a friend, electronics technician and he said,
‘contrary to common belief, unlike electricity, the radio magnetic waves flow on the surface
and not at the core of the cable/pin’.
makes sense ?

ED1 : after posting went and tried on one of the dongles leaving ~1mm gap
as per image. for about 5 aircraft the message rate went from 4.2 to 6.4 or 6.5
so I guess it proves the point. surely for 50 aircraft ~400m/sec will jump to ~600 !

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Correct, it’s called the skin effect. High frequency alternating current flows through the outer layer of the conductor. This is why efficient antennas use hollow conductors that are big in diameter.

But in this case, it may be mechanical rather than the skin effect, but I’m not complaining.

Looks like I’m back in the ‘big leagues’. I have not seen these numbers and distances since September 2017.

This time I have the other setup to compare. While before loosening up the plug the ‘deluxe’ setup was only 10-15% better than the ‘poor man’s’ setup, the difference now is up to 150%. Hard to believe, but true.

Time for a happy dance.:grin:

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Are you sure you have the right N-connector? The 75 Ohm version has a much smaller pin.

I have no idea, never thought about it. It’s one of those eBay ‘specials’, so who knows? Nothing mentioned in the description.

I have also purchased N male to F female adapters, and the F male does not match the adapter’s thread, so money wasted.


Thanks, @abcd567.

I noticed that the price has increased. I don’t need it now, it was a preemptive purchase.

There is also a difference between F and SMA connectors.
They look similar.

If you mean the RP-SMA, yes. I don’t know about the F differences.

Excellent test!!!


most welcome :smile:

No, SMA to F. They look similar to the eye but are a mm or two different.

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I have them as well, but they fit ok.