Lol 
Weren’t they the same ones who used to call about not finding the ‘any’ key on the keyboard? 
Same gain setting on both ProSticks?
[quote=“BartJr”]
Yes, 42 dB on both systems before, during, and after the test
System 1:
Quick Spider + 12ft RG6 coax + FA Filter + ProStick + OrangePiPC + Armbian + dump1090-mutability
System 2:
FA 26" antenna + 4ft RG6 coax + FA Filter + ProStick + RPi model2 + Piaware img (SD card) 3.1.0
Both system at 0.5m horizontal and 1m vertical distance with each other, indoor, near a very large wall sized glass window.
Suggest you add the FA 1090 filter to the Pro Stick Plus.
It made for a big increase in aircraft positions for me.
The decision was made to put the filter after the built-in amp. I didn’t think there would be many cases where the built-in amp would be saturated.
Prostick
built-in amplifier —> receiver
Prostick Plus
built-in amplifier —> built-in Filter —> receiver
Adding a filter on the input of the prostick plus will prevent the built-in amplifier from be saturated.
Prostick Plus with external filter
external filter → built-in amplifier —> built-in Filter —> receiver
An external filter + prostick plus seem to be marginally better than an external filter + prostick.
A major point of the prostick plus was to not need an external filter but it looks like some people might need it to get max messages.
[quote=“david.baker”]The decision was made to put the filter after the built-in amp. I didn’t think there would be many cases where the built-in amp would be saturated.
Prostick
built-in amplifier —> receiver
Prostick Plus
built-in amplifier —> built-in Filter —> receiver
Adding a filter on the input of the prostick plus will prevent the built-in amplifier from be saturated.
Prostick Plus with external filter
external filter → built-in amplifier —> built-in Filter —> receiver
An external filter + prostick plus seem to be marginally better than an external filter + prostick.
A major point of the prostick plus was to not need an external filter but it looks like some people might need it to get max messages.
[/quote]
Thanks for the advise. Your reasoning is very logical. Will try ProStick Plus with FA external filter.
I’ve got a plus inbound and I have the FA antenna. Please let us know what you determine. Thanks.
Sure I will post the results when I conduct the trial of ProStick Plus with external Filter.
However, these results are specific to each site and may not be applicable to another site due to huge differences in air traffic and interfering signals (from cell phone towers or similar RF radiators) from site to site.
I understand. I do have the filter already, so if that works better, I am in good shape. Thanks for all your expertise, and your willingness to share.
I’m using the Blue dongle with the FA antenna (have run it with both FA antenna) no issues - something else is going on. Did reboot between tests? If so, don’t. Simply swap the dongle and restart dump1090. Can replicate those results?
Yes, I did shutdown briefly, every time I changed the dongle.
Ok, will repeat the test. This time no shutdown or reboot, simply change dongles in live condition, and restart dump1090-fa after every time the dongles are swaped.
Repeat test of ProStick PLUS, this time with FA Filter
System 2:
FA 26" antenna + 4ft RG6 coax + FA Filter + ProStick + RPi model2 + Piaware img (SD card) 3.1.0
Maybe try optimising the gain settings when using the pro stick plus(with and without a filter).
It really makes you wonder if your blue Pro Stick Plus has a bad filter. Do you see a big drop when you use the orange Pro Stick without the FA filter on each antenna? If it’s a bad filter in the blue Plus, then maybe the difference between antennas is due to reception bandwidth (quality factor) of the spider vs. the FA antenna. Amateur radio operators, correct me if I’m wrong, but doesn’t a shorter antenna generally have a higher Q factor and thus have a filtering effect?
Good suggestion.
Ok, I will test & compare ProStick (Orange) on both Spider & FA antennas, under two conditions (i.e. with and without FA filter) and post the results.
You seem to be right. Please see this post:
http://discussions.flightaware.com/post200621.html#p200621
The 1/4 wave ground plane (cantenna) was tested by brainroyal using a Vector Impedance Analyser, and he remarked:
“The best part about this antenna is it’s deafness to frequencies that are out of band for ADSB.”
After trying out the new USB plus stick (with my different systems) all which are running on a pi-3 v3.1, all with short run times 7 coax, … my conclusion is that if you have a home made antenna it does wonders. However, if using this with a FA antenna it actually has demonstrated a decreased in performance vs. using the original pro stick and filter. All pi’s are using default configurations, with full power restart between changes, with no tweaking of settings. So your mileage may vary for you location? So I am dumbfounded with the statement of percentage gain using the new Plus USB stick.
I use Piaware 3.1 img, and have changed the settings Receiver Gain to 42 dB by following method:.
#opened file "piaware-config.txt" in text editor nano by following command
cd ~
sudo nano /boot/piaware-config.txt
# in the open file, scrolled down to receiver options, and there found a line rtlsdr-gain -10
#changed -10 to 42
#saved the file
ctrl+o
#closed the editor
ctrl+x
#in order the changes to take effect, restarted dump1090-fa (alternatively reboot the Pi)
sudo systemctl restart dump1090-fa
#Then checked status, it showed dump1090-fa has restarted with new gain setting
sudo systemctl status dump1090-fa -l
.
Currently using abcd567’s soda can antenna at the house and at our office.
After I’ve collected a week’s worth of data at the house, will be removing the filter and letting it run for another week. Will post results after I’ve analyzed both runs.
Then I’ll be doing it again with specific gain settings instead of auto-gain.
I’m pretty sure the cantenna does NOT need a filter. It’s already got a pretty good bandpass characteristic, but we’ll let the data tell the story.
If I haven’t posted results by the 25th, someone poke me with a stick and remind me. 