FlightAware Discussions

Please analyze my ADS-B signal level

Please analyze my ADS-B signal level

I recently installed the Graph1090

Figure 1
photo_2020-10-06_16-25-40
p1

The configuration is as follows:
piaware4.0 - FlightAware Pro Stick Plus - FA filter (blue) - 2m cable - 5.5dbi antenna
*Located in the countryside with very little frequency noise.
**The height of the antenna is 20 meters from the ground.
*** gain = max

Figure 2
dump1090-localhost-signal-2h (1)
p2

The configuration is as follows:
piaware4.0 - FlightAware Pro Stick Plus - 1m cable - uputronics preamp (1090mhz) - FA filter (Light Blue) - 9dbi antenna
*Frequency noise is located in the heart of a very large metropolis.
**Antena is the top floor of the building (in-house) about 130 meters from the ground.
*** gain = 22.4

The two pictures are the signal level of the high-volume time zone, from PM1 to PM5.

I’m looking for the proper gain for the Figure 2 antenna.
Which of the two is the better signal?
Is there anything to be improved?

Sometimes they catch planes over 240 nm (mainly at night).
On some days, on average, 180nm is the maximum coverage.

I’ll be waiting for your advice.

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IMO Figure 2, on a FA Stick Pro (Blue) the weakest signals can be approx -30/-40 dBFS
Take a look at this post

[quote].
Is there anything to be improved?
[/quote]

Situation 1 (countryside):

  1. Get an LNA, i.e. the RTL-SDR ADS-B Triple Filtered LNA which has an excellent performance (matches the Uputronics and even outperform it in busy areas). You won’t need an additional filter. Take notice that it has to powered via Bias-T, so you will need another dongle with build in Bias-T (i.e. NESDR SmarTee, RTL-SDR V3) OR (preferably) a biaser with USB. The LNAs’ power requirements are: 3.3-5V, 150 mA.
  2. Replace the antenna with a better performing one. Mind you: A good antenna doesn’t have to be expensive.

For situation 2 (and 1):

  1. Get an Airspy mini ($99) or R2 ($169) dongle. However, if you want maximum performance, these dongles require more computing power and the law of diminishing returns is in effect.

For situation 1 and 2:

  1. Place the antenna outdoor, as high as possible with a free view
  2. Optimize the gain: see this post and this post. @wiedehopf has written an automatic gain optimization script.

In fact, reading the entire Thoughts on optimizing gain-thread will teach you everything you need to know about gain optimization.

edit: typo

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