Messages per second / Visible Flight data / Status on FA Receiver


#1

Hi everyone,

New kid on the block here with some questions I’m sure has been answered 5022 times before but I’ll throw it up here anyway.

I’ve read through the forums of people getting 500+ messages per second.

Looking at the log, it seems i’m only averaging 140-150~ with only 50~ processed.
what does this mean?

[2018-04-26 10:26 AEST] mlat-client(875): Receiver: 105.6 msg/s received 40.6 msg/s processed (38%)
[2018-04-26 10:26 AEST] mlat-client(875): Server: 0.0 kB/s from server 0.0kB/s TCP to server 0.4kB/s UDP to server
[2018-04-26 10:26 AEST] mlat-client(875): Aircraft: 5 of 6 Mode S, 9 of 11 ADS-B used
[2018-04-26 10:30 AEST] 85057 msgs recv’d from beast-splitte (579 in last 5m); 85057 msgs sent to FlightAware
[2018-04-26 10:35 AEST] 85742 msgs recv’d from beast-splitte (685 in last 5m); 85742 msgs sent to FlightAware
[2018-04-26 10:40 AEST] 86407 msgs recv’d from beast-splitte (665 in last 5m); 86407 msgs sent to FlightAware
[2018-04-26 10:41 AEST] mlat-client(875): Receiver status: connected
[2018-04-26 10:41 AEST] mlat-client(875): Server status: synchronized with 50 nearby receivers
[2018-04-26 10:41 AEST] mlat-client(875): Receiver: 148.4 msg/s received 51.9 msg/s processed (35%)
[2018-04-26 10:41 AEST] mlat-client(875): Server: 0.0 kB/s from server 0.0kB/s TCP to server 0.6kB/s UDP to server
[2018-04-26 10:41 AEST] mlat-client(875): Results: 2.9 positions/minute
[2018-04-26 10:41 AEST] mlat-client(875): Aircraft: 2 of 6 Mode S, 17 of 26 ADS-B used
[2018-04-26 10:45 AEST] 87079 msgs recv’d from beast-splitte (672 in last 5m); 87079 msgs sent to FlightAware
[2018-04-26 10:50 AEST] 87658 msgs recv’d from beast-splitte (579 in last 5m); 87658 msgs sent to FlightAware

I am using the 60cm FA Vertical antenna mounted to a pole on the side of the house with no filter (I think I read somewhere that it is not recommended to run a filter with these antennas?)
Are these antennas Ground plane dependant? would it worthwhile fabricating up some radials around the bottom?

Would it be worth trying to modify the gain up / down? does the FA receiver have Auto Gain Adjustment?

Next question is regarding the visible flights on the tracker on my screen vs what is shown on the website.

for e.g I am around 100km away from Sydney International Airport which sees hundreds of flights per day yet I do not see any of these show up on my personal feed - what is the basis behind this?

Third question… at night past 11pm the MLAT / Radio status icons turn yellow / orange. is this just due to no traffic overhead and it timing itself out?

Thanks all!


#2


Alternate image provided above to show the difference.

I know the first image was on a different day, but the airport is just as busy.


#4

I get up to 1500 messages per second. I see 3000-4000 aircraft per day.
I am located in busy NYC near 3 major airports and numerous other airports.
Radar and tcas responses generate a lot of extra traffic

Check the receivers near you.
It isn’t that busy in Aus. Curfews limit the nighttime traffic.
I’ve flown helos and fixed wing there and it is pretty quiet.

I use cavity filters with my setup. A dozen cell towers with 300m.
The Fa filter may help. I would start by looking the the gain optimisation posts.
You could also try the hab/nevis amp/filter.
Which dongle are you using?

Also check www.heywhatsthat.com to see what you can expect for range.

Nice to see an F call in the group. My kids hope to get their licence soon.


#5

Thanks for the reply! I know at Sydney the curfew is around 11pm, but during the day has me a bit perplexed.

I am using the latest flight aware module with the touch screen on the front.

My closest airport is a few kms away, it’s a shame that the Cessnas there don’t run any transponders. As I’m right below a training pattern and can see them doing loop after loop.

I just looked at a receiver that is nearish to me but I am. Unable to see the messages/s.

I have received signals from 400km away according to my statistics which was promising.

Am confused why I don’t see the ones hanging around syd airport.


#6

Ah, you have a flight feeder. Not much you can do with that except move the antenna.

There are a lot of piawares in your area without MLAT enabled. A bit of a shame.

Maybe give it time to settle down. The ridge of the Northern Suburbs may be blocking your reception.

I think I flew to Warnervale for one of cross country navs. Did a few IFRs into Williamtown too.
Took a Bell 206 to Robert’s restaurant in the Hunter. Took me three tries. Once was too windy. They second time I had to land at the old Gosford airport due to weather (was a model aircraft park at the time).

Fyi de VK2TCW and K2TCW.


#7

ahh okay, dang.

there are a few i’ve seen!, I know who runs the Radscape, that’s at the VK2RAG repeater site near me so I’ll hit them up and see what they may be getting.

I went to the “Hey Whats that” but have NFI what i’m looking at with it.
I do have a small amount of trees blocking direct line of sight about 50m away heading west.
Happy to send the URL through, as I don’t want to give away my exact location here

It’s nice to see someone up that has local knowledge! :slightly_smiling_face:


#8

Have a look at https://www.heywhatsthat.com/?view=SXP5JSJ6

It is based on the approximate location that Flightaware has on their website that may be many km inaccurate.

When you have the website scroll down to the map and click on the Up In The Air button in the top right to calculate your 10000 and 30000 ft view and then click on the - in the bottom right corner to zoom out till you see your range rings.

That is a start.

Where is your antenna mounted? I assumed outside in the clear at 25 feet above ground in the clear.

S.


#9

Great, thanks, The location that’s visible on the page is different to the actual device (I set it to show within 10km) but still close!

Below is the accurate location but still no difference really.

Antenna is located on the side of the house

about 1.5m above roof height. Top of the antenna sits just below the bracket for the other one on top of the mast.

mast extends over 2m from the top of the roof and would be easily 25ft from the ground.

See:

Pretty clear line of sight surrounding it,


#10

When using HeyWhatsThat to create a panorama always use the URL

https://www.heywhatsthat.com/?refraction=1

and enter the value 0.25 for Refraction. This will show you what you can see based on 1090MHz radio waves through air, which is what we’re using it for.

HeyWhatsThat_refraction

If you use the URL without that last ?refraction=1 part then you have no option to enter a value and it will default to 0.14. This gives differently sized rings based on what you can see, ie based on light through air, which is what the site is more commonly used for.


#11

Okay, done and redid it.
not really any visible differences I could see?

Check PM’s for direct link


#12

It is a bit hard to see from that photo.

How far is the ADS-B antenna set off from the mast and where does the coax for the ground plane go?

S.


#13

Will attempt to get a better photo later today if the weather is nice.

It’s not offset very far from the actual pole itself, only a couple of centimeters (the length of the bracket) I have started to look for a L / J pole extension that I can clamp onto the mast which would put it approx 30cm offset from the mast.

Coax is running through the brickwork currently to the receiver until I rerun it through the roof space


#14

.
The heywhatsthat range rings can be permanently added to dump1090-fa map and dump1090-mutability map as shown in above screenshot.

The step-by-step method is given in April 2017 thread Bake a Pi.

  1. dump1090-fa map
    :point_down: Scroll down to:
    “8 ):** ADD TERRAIN LIMIT RINGS (OPTIONAL)**”

  2. dump1090-mutability map
    :point_down: Scroll down to:
    11) ADD TERRAIN LIMIT RINGS (OPTIONAL)

.
This was already taken care of in the wget command of the April 2017 posts linked above,

.


#15

The plots produced above in this thread were done on the site, not using wget. If using the site then use the refraction flag to enable the option or you will get slightly incorrect results.

I covered this in detail in HeyWhatsThat horizon discrepancy


#16

It is much more handy to have heywhatsthat rings plotted permanently on the SkyView Map, rather than on a separate map on site.


#17

Thanks for the link to the thread. I have somehow missed it.


#18

I agree, if you use an API call to grab the JSON data you can include the refraction parameter as you mention. It’s also worth editing script.js and changing the colour and/or the width to better make them stand out. I have mine set to blue and 2px wide.

But if you want to look at the Hey What’s That site to see what your limits are, or if you send someone there, or if you look on behalf of someone, as was done above, then please use the ?refraction=1 URL so that you can similarly add the correct refraction parameter, or else you will get incorrect rings based on a default of 0.14.

It doesn’t matter too much – you still get a reasonable idea of the limits, they are wrong by several nautical miles. Always using the ?refraction=1 URL in the browser and specifying 0.25 eliminates the problem entirely.


#19

I have one of those orange FlightFeeder and also my own Pi. On both devices, I had to adjust the gain from the default AGC (-10 value) to something lower, because of the proximity with the airport. Lots of strong signals close-by will overload the receiver.
In the “Radio” menu, you can see the number of “clipped” messages in the past minute (and more). You can lower that number, by adjusting the gain in there.
Note that there is a software quirk there - once you have selected the new gain (tapping or dragging the slider) and hit “Apply”, the screen will be stuck there. Wait 10 seconds and hit “cancel”, it will bring you back to the previous menu, and the setting will be applied. Wait there a little bit and see the number of messages/second - if they are higher, then all is good.
You can go back to the status screen and it will show again the clipped messages (after 1 minute). You can’t go all the way to zero, but at least you should not have thousands there.
If you don’t feel like this is clear, please contact the FA support email listed on the box.
Also, install the filter inside the house, before the receiver, if they provided you one.

The pics below are taken at 6AM, at my location. Don’t pay attention to my Gain, I just slide it all the way to zero for this demo. Note that the “Max Gain” is un-ticked (that is the AGC setting).





FlightFeeder Orange Gain
#20

Is there a way to see similar stats for clipped messages in PiAware? It seems it would be helpful in assessing optimum tuner gain.


#21

Not stats, but using the ADS-B Receiver Project graphs, you get an idea when the ‘separation’ between the noise and max signal lines shrink, and gets closer or crosses the -3 dbfs line.