JetVision vs. FlightAware USB Sticks

[Burton_Ped]

I've been feeding data into FR24 for three years (today!) and still use the original JetVision USB dongle that I bought at the time of original installation. I have added a FlightAware 1090 MHz ADS-B Bandpass SMA Filter (Dark Blue) to filter out Mobile Phone mast signals, but wonder whether there would be any benefit from replacing the JetVision stick with the FlightAware Pro Stick?

I'm currently getting about 225nm range, which if I plot on a map...

Flightradar Range.JPG

..seems pretty close to the theoretical maximum distance for aircraft between 10,000 and 45,000 feet based on my location:

Flightradar Theoretical Range.JPG

Would I see any benefits from changing to the FlightAware Pro stick?

Secondly, if I did change, is it a simple hardware swap and reboot of the Pi, or do I also need to make some configuration changes?

[abcd567]

1. Which antenna are you using? A better antenna may improve max range / number of aircrafts.

2. There are two USB Dongles offered at Jetvison site. Which one of these you are using?

https://shop.jetvision.de/ADS-B-USB-Dongles/en

53199_1.jpg . RTL-SDR-R820T2-RTL1090_m.png

[Burton_Ped]

I bought the ADS-B USB Dongle + "SCO-1090-MCX" Antenna (1090 MHz) bundle which came with:

1 x ADS-B USB Dongle (R820T2) without Indoor Antenna (the black one in your picture above)
1 x "SCO-1090-MCX" Antenna, incl. Cable for ADS-B Dongle

The antenna is 28ft (8.5m) above ground level

[abcd567]

You have a good antenna with good cable, and good antenna height. Great!

Your jetvision's black dongle is a basic dongle. It does not have an amplifier (LNA) or Filter chip.

The Flightaware ProStic (orange) has an amplifier (LNA) chip, but no filter chip.

The Flightaware ProStic Plus (blue) has an amplifier (LNA) chip and a filter chip (SAW) also.

If you replace jetvision's black dongle with Flightaware ProStick Plus (blue), your reception is very likely to improve.

[Burton_Ped]

As I have the Blue Filter, could I just go for the Orange Stick and put the filter inline or is there less noise having the whole lot on one stick?

Would I need to make any config changes or is it just a hardware swap?

Sorry for all the questions!

[abcd567]

As you alrwady have a filter, orange ProStick will be ok.

No you dont have to make any config changes. However it will be beneficial to try different gain values.

[Burton_Ped]

Thank you for the advice. I've put an orange one on order so will swap it over and update the post with the impact

[abcd567]

Install performance graphs now.
These will make comparison between performance of two dongles very easy.
It will also help you in trying to tweak the gain value after you install the Orange ProStick.

Command to install graphs:

sudo bash -c "$(wget -q -O - https://raw.githubusercontent.com/wiedehopf/graphs1090/master/install.sh)"

To see the graphs, open your browser and type following address:

IP-of-Pi/graphs1090/


If you check the graphs immediately after installing, you will see blank graphs.
After installation, wait for at least 20 minutes for graphs to collect enough data to start plotting.

THe graphs keep on updating their data every 10 minutes or so. However if you want to manually update the graph data, issue the following command, and the graphs will start updating data:

Command to update data:

sudo /usr/share/graphs1090/graphs1090.sh 24h

[Burton_Ped]

I installed Graphs last week actually after starting my investiagtions into what I could do to improve coverage. I'm currently getting 0.0% of Messages > -3dBFS

Capture.JPG

You may be able to interpret the signal level graph better then I can

Capture2.JPG

[Burton_Ped]

The FlightAware USB stick arrived yesterday morning, thanks to quick shipping by The Pi Hut. After installing it and quickly rebooting, the impact was immediately noticeable. Over the subsequent 24 hours I was able to see -

Maximum Range: Up 29% to 290 Nautical Miles
Message Rate: Up 30% to 650 Messages per Second
Position Rate: Up 52% to 32 Positions per Second
ADS-B Aircraft Tracked: Up 33% to a maximum of 173

I am still seeing 0.0% of messages > -3dBFS, so I'm assuming the existing gain settings are fine (-10).

It's obvious that this was a worthwhile upgrade. Thanks abcd567 for your help and support in answering questions

[abcd567]

Great! Well done

[Burton_Ped]

An interesting development

I upgraded dump1090 from the v1.14 that comes with the FR24 PI Image to v1.15 to take advantage of the improved mapping now that the range had increased. I used the instructions in this post :

https://forum.flightradar24.com/forum/radar-forums/flightradar24-feeding-data-to-flightradar24/12429-pi24-replace-dump1090-v1-14-pre-build-package-of-dump1090-v1-15

I used the automated Option 1. No issues.

After reboot, I noticed that the percentage of messages > -3dBFS jumped from 0.0% to more than 20%. You can see the sudden change here:

Capture.JPG

It seems odd because:

1. I shutdown the PI to install the FlightAware stick and then powered on (so a reboot)
2. I didn't change any settings before installing the FlightAware stick and upgrading dump1090 to v1.15
3. I've double checked and the gain in /etc/default/dump1090-mutability GAIN is set to MAX and procargs in /etc/fr24feed.ini is set to -10 i.e. the same as before the dump 1090 upgrade

I obviously need to now reduce the gain, but am just wondering why the upgrade to v1.15 and subsequent reboot seemed to cause the sudden increase in strong messages rather than the boot after the FlightAware stick was installed when the settings haven't been changed?

[abcd567]

We need to see your fr24feed settings. What is output of following command?
(Remove fr24key value from the post)

cat /etc/fr24feed.ini.

[Burton_Ped]

Here are the results:

receiver="dvbt"
fr24key="nnnnnnnnnnnnnnnn"
bs="yes"
raw="yes"
logmode="2"
procargs="--gain -10 --lat nn.nnnn --lon -n.nnnnnn"
windowmode="0"
mpx="no"
mlat="yes"
mlat-without-gps="yes"
bind-interface="0.0.0.0"

In case this is useful, you can see what happened to the signal level after the reboot last night:

Capture2.JPG

[abcd567]

(1) With setting receiver="dvbt", the gain and other setting in IP-of-Pi:8754/settings.html (same as in file /etc/fr24feed.ini) over-ride settings in file /etc/default/dump1090-mutability. Therefore do NOT bother to change settings in file /etc/default/dump1090-mutability


(2) In file /etc/fr24feed.ini (or in page ip-of-pi:8754/settings.html), reduce gain setting from -10 to say 49, wait for few hours, then observe the result. Most likely situation will improve. Again reduce gain to say 45, wait for few hours, and then observe the results. This is the trial-and-error method to find best gain setting.