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 Post subject: Re: Gain Adjustment...
PostPosted: Sat Oct 08, 2016 11:30 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
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Location: Toronto CYYZ
@Boeings
Image cannot be seen.

You have posted image from local IP of your Pi, hence it can only be seen from within your LAN.

[ img]http://192.168.0.15/graphs/dump1090-localhost-signal-24h.png?time=1475986399.57[/img ]

You have to first upload the image to an image hosting service, and use the sharing url provided by the hosting service for your uploaded image.


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 Post subject: Re: Gain Adjustment...
PostPosted: Sat Oct 08, 2016 11:57 pm 
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Boeings - FlightAware user avatar

Joined: Sun May 29, 2016 2:09 am
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Location: Sydney
I put in a link, thanks.


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 Post subject: Re: Noise
PostPosted: Sun Oct 09, 2016 3:50 am 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
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Boeings wrote:
Hello, my noise level drops from -20dB to -30dB, in line with local curfew (GMT +11). Does that mean that some positions are being treated as noise?

Thanks, B

http://imgur.com/E7GhmGY


May be the very weak ones, or the very strong ones, are treated as noise.
As long as the noise is below -20 dBFS, it should be ok otherwise.
Compare your's with mine, pattern is same.


Yours: Off Peak 12:00 to 19:00 UTC (23:00 to 06:00 Local Time)
Image


Mine: Off Peak = 00:00 to 06:00 Local Time
Image


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 Post subject: Re: Gain Adjustment...
PostPosted: Sun Oct 09, 2016 4:18 am 
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Boeings - FlightAware user avatar

Joined: Sun May 29, 2016 2:09 am
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Location: Sydney
abcd, thanks, I am trying to figure out what other noise goes down at night? Maybe cell phone traffic?

B


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 Post subject: Re: Gain Adjustment...
PostPosted: Sun Oct 09, 2016 4:41 am 
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abcd567 - FlightAware user avatar

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Boeings wrote:
abcd, thanks, I am trying to figure out what other noise goes down at night? Maybe cell phone traffic?

B

Yes, sure. The air traffic off-peak hours are same as hours when people sleep. The cell phone usage is sure minimum during this period.


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 Post subject: Re: Gain Adjustment...
PostPosted: Sun Oct 09, 2016 7:12 am 
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obj - FlightAware user avatar

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Probably more significant is that when there are fewer aircraft around, there is less chance of collisions between messages producing an undecodable garbled message, and there is less chance of receiving distant messages that are slightly too weak to be decoded. Both are counted as "noise" (it's not the noise floor that is measured, it is just the total power of everything that was not a successfully decoded message).


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 Post subject: Re: Gain Adjustment...
PostPosted: Sun Oct 09, 2016 1:50 pm 
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NWGM - FlightAware user avatar

Joined: Fri Jul 01, 2016 9:16 am
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I took another way.

1. Find out where are my physical borders. Heywhats = 400 km max distance (for a plane at 13000 meters)

2. Find out my gain setting where close planes block my receiver. At gain settings higher than 45 at 1 km .

3. Find out at what gain setting can the maximum distance of 400 km (13000m) be reached. Gain setting between 39 and 41.

4. Find out at what hight I should see a landing plane at an airport 90 km away. 500m . Gain Setting also between 39 and 41.

5. Took 41, because you cant do tricks with physics. (Except weather or other conditions.)

I can see planes landing at 350 meters and planes up to a distance of 435 km. That is more, than physics will allow.

I should be happy with that.


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 Post subject: Re: Gain Adjustment...
PostPosted: Sun Oct 09, 2016 4:39 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
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@NWGM
Sie sind intelligent.


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 10, 2016 12:59 am 
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NWGM - FlightAware user avatar

Joined: Fri Jul 01, 2016 9:16 am
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@abcd567 thanks back,l I only did, what you described before.

And this way seems to be the only one to come to an end, hunting for better statistics like others.

If there are no more planes in my region, I can't change it. I can only try to get the best
out of physics, and thats it.


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 10, 2016 2:54 am 
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Joined: Fri Apr 01, 2016 3:29 am
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Location: Fort Lauderdale
Nitr0 wrote:

Possible gain values for RTL based devices:
0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 -10 agc

Any gain number maybe used, but dump1090 will calculate and use the closest value from above.



Interesting.

I didn't know that.


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 Post subject: Re: Gain Adjustment...
PostPosted: Fri Oct 14, 2016 3:40 am 
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Boeings - FlightAware user avatar

Joined: Sun May 29, 2016 2:09 am
Posts: 27
Location: Sydney
Hello, I have reduced gain from -10 to 40, but dump1090 graph 'ADS-B Message Rate' shows more red grass, legend = Messages > -3 dBFS/hr.

Does this mean there are more strong messages, or more weak ones?

Thanks, B


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 10:10 am 
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jcinnb - FlightAware user avatar

Joined: Wed Sep 14, 2016 4:40 pm
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Just do it:

Here is dump view after gain adjustment. For same time period I am getting twice the planes, and three times the messages after adjusting gain. Really surprised at the extent of improvement!

Image


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 10:32 am 
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jonhawkes2030 - FlightAware user avatar

Joined: Tue Jan 05, 2016 4:15 pm
Posts: 1064
Location: NYC
How high is your antenna?
You get about the same range as my indoor, 2nd floor, FA antenna (maybe 60ft AMSL, 15ft AGL)
http://flightaware.com/adsb/stats/user/ ... tats-17065

Gain adjustments significantly improved my setup. With a good external antenna,LMR400 coax, cavity filter and FA 1.0 dongle, I had to reduce the gain to 38db for my location(every location is different).
FYI, removing the filter and I go from 200 to 2 aircraft(lots of noise).


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 11:17 am 
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My antenna is not really mounted yet, I guess I should have mentioned that. It is on the front porch, still waiting to get it on roof, but nevertheless, the increase after adjusting gain was dramatic.


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 12:01 pm 
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jonhawkes2030 - FlightAware user avatar

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jcinnb wrote:
My antenna is not really mounted yet, I guess I should have mentioned that. It is on the front porch, still waiting to get it on roof, but nevertheless, the increase after adjusting gain was dramatic.


You should see a huge difference when the antenna is mounted nice and high.
Even at <100ft amsl, I can get 100 hits a day over 200NM.


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 12:07 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
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Location: Toronto CYYZ
@jcinnb
How did you get maximum range plot on dump1090-fa, similar to what we get on VRS?


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 12:17 pm 
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abcd567 wrote:
@jcinnb
How did you get maximum range plot on dump1090-fa, similar to what we get on VRS?


I am not trying to be a smart azz, but I followed your instructions, I think! I have configured so many times I honestly don't remember the specific post I used, but I rely on your instructions so much you are probably the suspect!!!


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 12:23 pm 
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jcinnb - FlightAware user avatar

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jonhawkes2030 wrote:
jcinnb wrote:
My antenna is not really mounted yet, I guess I should have mentioned that. It is on the front porch, still waiting to get it on roof, but nevertheless, the increase after adjusting gain was dramatic.


You should see a huge difference when the antenna is mounted nice and high.
Even at <100ft amsl, I can get 100 hits a day over 200NM.


Right now I am totally obstructed to west and south. The antenna is under porchroof, but with clear view north and east.

I am going to be almost 25 feet higher, and pretty much unobstructed. Unfortunately, with first the hurricane and then flooding, my "roof" guy has been tied up. It will be up there soon, I hope.


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 1:28 pm 
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abcd567 - FlightAware user avatar

Joined: Sat Feb 15, 2014 3:08 am
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jcinnb wrote:
abcd567 wrote:
@jcinnb
How did you get maximum range plot on dump1090-fa, similar to what we get on VRS?


I am not trying to be a smart azz, but I followed your instructions, I think! I have configured so many times I honestly don't remember the specific post I used, but I rely on your instructions so much you are probably the suspect!!!

No, It is not me. I never posted anything about dynamically plotting maximum range like the way it is done by VRS.
See this post by lignumaqua: post186780.html#p186780
Have you installed lignumaqua's fork of dump1090 (https://github.com/lignumaqua/dump1090)?


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 Post subject: Re: Gain Adjustment...
PostPosted: Mon Oct 17, 2016 6:30 pm 
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jcinnb - FlightAware user avatar

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OK, I got it now, I was riding with my daughter and was not real focused.

Those are not range rings, but the altitude rings from the HeyWhatsThat site. You had me scared there for a minute.
:x


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 Post subject: Re: Gain Adjustment...
PostPosted: Tue Oct 18, 2016 4:08 am 
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Well I have successfully been running the scripts from this thread and getting some good data from my 2 units. My question is, using the 3 data sources from such script testing, messages, positions and aircraft, which specific data source do you aim to use, to get the best db setting for optimum detection settings??

Now what I have been doing, is running various tests, at different times of the day or night, at different lengths of time say from 5 mins to 90 mins and getting the averages, as produced by the script report, putting that data together per type and gaining an overall average. Now I know that such data will change in relation to how busy the airspace is that your are scanning etc. But I am thinking if you use data from all times and different traffic levels, you should get a good overall average across each data field. Sometimes the different averages for messages, positions and aircraft will be fairly obvious, a certain db level will stand out as the optimum setting, however other times, as more data is added to the overall averages, there may be a difference at what db setting is the best between positions, messages and aircraft.

So what should be the data source, in such a situation of discrepancy of ideal or best db setting , should you pick, the messages, positions or aircraft. Which is the most relevant for good detection??

Jeff


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 Post subject: Re: Gain Adjustment...
PostPosted: Sat Nov 05, 2016 4:05 pm 
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jcinnb - FlightAware user avatar

Joined: Wed Sep 14, 2016 4:40 pm
Posts: 136
Post power spike meltdown:

Had everything working great and then had a power spike on Tuesday or Wednesday. Ended up having to copy a backed up image, since Piaware started running erratically.

I am using the Piaware 3.1 image.

Well,
I am having trouble now, running the Gain Analysis script. Everything else is fine.

Using Bart's script, I get the following error, kind of randomly:
pi@raspberrypi:~ $ sudo ./optimize-gain-piaware3.py
test 1 of 3
gain= 49.6 messages= 3721 positions= 137 planes= 23
gain= 48.0 messages= 3296 positions= 133 planes= 23
gain= 44.5 messages= 4700 positions= 266 planes= 32
gain= 43.9 messages= 4372 positions= 237 planes= 35
Traceback (most recent call last):
  File "./optimize-gain-piaware3.py", line 24, in <module>
    s.connect(('localhost',30003))
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
socket.error: [Errno 111] Connection refused


Sometimes the script would run, sometimes, like above, it would run a couple of trials, sometimes it would just freeze. "Appeared" really random. I changed the wait time from 2, to 3 to 4, still "kinda worked"

I then went with ignumaqua's script. It runs, but I get a Restarting dump1090-mutability message before each trial. The final table, summary, is fine, however!

Back in May, RadioAstronomy reported a similar issue. He apparently fixed it, but was advised he had used "bad code," so he deleted his code.

Can anyone tell me what is going on? Appreciate it. I am not wed to anything or any script, I am happy to change scripts, I just want the script to work like it used to.


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 Post subject: Re: Gain Adjustment...
PostPosted: Sat Nov 05, 2016 8:53 pm 
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BartJr - FlightAware user avatar

Joined: Sat Jan 16, 2016 9:11 am
Posts: 142
Location: Austin, TX
jcinnb wrote:
Traceback (most recent call last):
  File "./optimize-gain-piaware3.py", line 24, in <module>
    s.connect(('localhost',30003))
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
socket.error: [Errno 111] Connection refused[/color]


This just means the gain script couldn't connect to dump1090 port 30003. Either dump1090 didn't start correctly, or dump1090 started slowly and wasn't ready when the script tried to connect. Hard to say why it would be failing sporadically for you even after upping the wait time.

(really i should make the script smarter to wait until dump1090 is ready rather than just waiting N seconds)


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 Post subject: Re: Gain Adjustment...
PostPosted: Sat Nov 19, 2016 12:52 am 
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myalias - FlightAware user avatar

Joined: Thu Mar 24, 2016 9:15 pm
Posts: 31
I graphed the output of the various amplification settings of the, and changed my gain from -10 to 44.5. The result? In the first 24 hours, I've gone from about 400k positions to about 500k, and from 2700 airplanes to 3100. That's not bad for having an open horizon for only 1/4th the sky. My hottest sector is in the 320-400km range. Equipment consists of a Pro Stick, filter, and FA antenna situated on the balcony.


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 Post subject: Re: Gain Adjustment...
PostPosted: Tue Nov 22, 2016 1:09 am 
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WarrnamboolCity - FlightAware user avatar

Joined: Wed Apr 06, 2016 6:23 pm
Posts: 29
Location: Warrnambool, Victoria, Australia
I have piaware3 working with dump 1090 fa on my OPi now. It is running on Armbian Jessie Server. I can't just edit the configure file by putting the sd card in the reader and editing the txt file. So, where is the file located so I can access via SSH? Currently, the antenna is a passive system so I am interested to see what affect changing gain has on reception.


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