Trial Run Results for Three Types of Whip Antennas

AnirbanSen

Member
Actually it doesn't look like it's working fine. It should look like the third one here:

View attachment 2977
(https://forum.planefinder.net/attachments/1569786921780-png.2977/)
I think i made the spectrum with lower gain, maybe 15 instead of the 30 given in the command from the thread.
But still you get the idea, yours is offset and just doesn't look right.
Check if making a spectrum with gain of 15 changes anything.
rtlsdr2.png

Pretty weird. Set at 1080Mhz. I've emailed rtlsdr admin. Let's see what he suggests.
 

AnirbanSen

Member
A replacement ticket has been created. Hopefully the new one will arrive in 3-4 weeks.
In the meantime, a new problem has emerged:
It appears that around 2am everyday, the signal falls off. The gain in dump1090-fa settings changes from -10 to 49.6.
It remains that way till I change the gain back to AGC and do a reboot.

Any idea what could be affecting this?
 

ab cd

Senior Member
Available in Planefinder forum also since Oct 28, 2017:
(Reminds me of Oblivian's comment. ;) )

 

AnirbanSen

Member
I think that was it. Wonder how it suddenly kicked it. Was a month ago I was testing that.
I also wonder why there is a huge difference between 49.6 and AGC. Signal is almost 4 times the strength at AGC.
 

ab cd

Senior Member
I think that was it. Wonder how it suddenly kicked it. Was a month ago I was testing that.
I also wonder why there is a huge difference between 49.6 and AGC. Signal is almost 4 times the strength at AGC.
For ADS-B signals, AGC does not act as Automatic Gain Control, it sets gain to almost 55.6 dB, which is 6 dB greater than 49.6 dB.
Every 3 dB increase doubles the signal, so 6 dB increase will double the signal twice, i.e. make it 2 x 2 = 4 times :)
 

AnirbanSen

Member
Apparently after installing the amplifier last month, I've now hit the leaderboard on flightaware for both number of positions and aircrafts.
I wanted to put all the devices in a box and yet ensure that signal quality and noise were no affected.

After putting them in the box, the noise has increased. I've put shielded a cardboard box with aluminium foil and also made partitions with pieces of cardboard covered in foil. However, perhaps some of the foil is probably creating the noise by reflecting the radio waves.

Any suggestions how to improve the design?

To recap, I have 12V DC going in, which is converted to 5V DC through a buck convertor. (Left compartment) This DC is fed to both the RPi and laptop cooling fan (whose power I could not measure even with a Digital USB Monitor) (Center compartment). The 5V is further reduced to 4.5V through another buck converter. (Left compartment, blue LED) The 4.5 V exits the box travelling the length of the box under an aluminum strip and goes to the Bias T (Outside the box). The Tuner (Right compartment) is connected with an OTG cable. The MCX connector of the cable from the Bias T goes through a small hole in the box and connects to the Tuner inside.

Pics are below. Couldn't rotate the image on the phone though.



IMG-20191124-WA0020.jpeg
IMG-20191123-WA0001.jpg
 

wiedehopf

Member
A 10 Ohm resistor is much less noisy than a buck converter to reduce the 5V to 4.5V

Doesn't have to be exact anyway.
 

AnirbanSen

Member
A 10 Ohm resistor is much less noisy than a buck converter to reduce the 5V to 4.5V

Doesn't have to be exact anyway.
True. That was inserted when the input voltage was 14V to power the satellite amplifier. Will see if I can get a 10-30 ohm 1/2W resistor.
In the meantime, someone is offering to get me from US a Tuner stick, is it worth going for the Flightaware ProStickPlus or the RTLSDR v3 tuner, is it worth it? With the Pi0, I won't be using it to enable the internal Bias T.
 

wiedehopf

Member
the v3 is a solid receiver combined with a filtered LNA, not that useful without.

the prostickplus is a good receiver standalone or with some input filtering.
you can also make it work with an amplifier before it but it brings its own amplifier and that can lead to overloads when combined with more amplification.
 

AnirbanSen

Member
I'll be setting up a 2nd receiver at my parent's house about 1200Km away. I think the v3 will be better if paired with rtlsdr's own LNA which appears to have good filtering.

I also came across tar1090. I think it's amazing.
Is it worth updating Graphs1090? I personally prefer the 1 hour timeline as its better for diagnostics. I think you should enable Graphs1090 to be available on a specific port as well. This would allow services like remote.it to access it and which would help when testing all the values remotely.
 

wiedehopf

Member
You can just make port 80 available to use graphs1090.

The 2 hour graphs don't display any less information than the 1 hour graphs, you can still see every single value recorded.
 

AnirbanSen

Member
You can just make port 80 available to use graphs1090.

The 2 hour graphs don't display any less information than the 1 hour graphs, you can still see every single value recorded.
Any data loss in an upgrade?

I'm quite enjoying tar1090 on port 80. Perhaps on port 47274 (GRAPH) in the future build?
 

wiedehopf

Member
You can just go to /graphs1090, i'm not sure what your issue with requiring a separate port is.

I can't think of a reason why a graphs update would cause data loss.
Lots of people update the graphs without issue, no guarantees though!
 

AnirbanSen

Member
You can just go to /graphs1090, i'm not sure what your issue with requiring a separate port is.
When I access my device remotely on remote.it (https://app.remote.it/) , I cannot access a sub URL. However, I can access specific ports which are converted into "Services".
Each Service maps to a specific port. 2 services cannot be assigned to the same port.
See below:


1574978386165.png

I can connect to port 22 (ssh, android terminal app), 8080 (skyview, android chrome) and even 80 (tar1090, android chrome) and 30053 (port 30053, android chrome). The application at each of those ports are piped through remotely.

When I am checking the antenna and where there is no wifi, I have no access to the internal LAN. I can however remotely connect to ssh via remote.it to login to see the console, or skyview to see if few planes or many planes are being detected. However, to see graphs1090, I have to use remote desktop on my PC to see the browser window since sub-URLs can only be seen within the same LAN. (My ISP does not support port forwarding so I cannot login via the router). Hope this clarifies the issue.
 

wiedehopf

Member
well do proper port forwarding with dynamic dns then ...

I won't support an additional port at this time.
It's not that hard but i hate making a work around for some stupid software.

You can always add it yourself if you understand lighttpd configuration.
(which might sound harsh as i'm aware most people don't. but as i said i don't feel like doing workarounds for software with stupid limitations)
 

AnirbanSen

Member
well do proper port forwarding with dynamic dns then ...
The ISP has blocked ports and they comply with requests. As a result, I cannot even access the router remotely anymore unless by this method. All such access has now been reserved to their "elite" tier. :rolleyes: I'll look into the lighttpd over the vacations hopefully.

And of course, this is your software (and freeware to at that) and it should reflect what you want with it.

But thanks anyway, I think tar1090 is by far the best vivid interface. Owe you a (extra) beer for that one. :cool:
 
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