GQRX configuration, RTLSDR and ADS-B Tuning.....

Hi All
I’m testing a new setup (well new antenna) for receiving ADS-B signals, but not really a radio guru thought I could pick the brains of Forum members in the radio field to offer insight into best way to setup GQRX for testing and equipment order (Software and Hardware)…

At present my running setup [Outside] (In order of connection);


1. Nooelec 6" 1090MHz antenna outside just above roofline
2. 15ft - RG174 cable
3. Nooelec - Ultra Low-Noise Amplifier (LNA) Module for RF & Software Defined Radio (SDR).
   Wideband and Linear 20MHz-4000MHz Frequency Capability with Bias Tee & USB Power Options,
   (Using USB powered option).
4. 8" RG58 SMA Male/Male.
5. Flightaware ADS-B Dual 978 MHz + 1090 MHz Band-Pass SMA Filter.
6. 8" RG58 SMA Male/Male.
7. Nooelec SMA DC Block in-Line 50 Ohm 50kHz-8GHz Connector Blocks DC Voltage from Your Radio
   or RF Test Equipment. Ultra-Low Insertion Loss (<0.3dB to 6GHz) and 2 Watts Maximum Power.
8. Nooelec - Premium RTL-SDR w/Aluminum Enclosure, 0.5PPM TCXO, SMA Input, RTL2832U & R820T2-Based Software Defined Radio. 

Current summary;
Coverage: ~160K-200K square Km
Range: ~400Km
Number of Aircraft: ~1700 per day

Current test setup [Inside]


1. Flightaware - 26" 1090 MHz ADS-B Antenna.
2. 4ft RG58.
3. Nooelec - Ultra Low-Noise Amplifier (LNA) Module for RF & Software Defined Radio (SDR).
   Wideband and Linear 20MHz-4000MHz Frequency Capability with Bias Tee & USB Power Options,
   (Using USB powered option).
4. Flightaware ADS-B Dual 978 MHz + 1090 MHz Band-Pass SMA Filter.
5. SMA Male/Male Adaptor.
6. Nooelec SMA DC Block in-Line 50 Ohm 50kHz-8GHz Connector Blocks DC Voltage from Your Radio
   or RF Test Equipment. Ultra-Low Insertion Loss (<0.3dB to 6GHz) and 2 Watts Maximum Power.
7. Nooelec - Premium RTL-SDR w/Aluminum Enclosure, 0.5PPM TCXO, SMA Input, RTL2832U & R820T2-Based Software Defined Radio.


Current summary;
Coverage: ~80K square Km
Range: ~300Km
Number of Aircraft: ~1000 per day

With the above setup I see the following from gqrx (On Tumbleweed), test system running Leap 15.2 (no desktop, just cli), dump1090-fa running, feed daemon running is to opensky network.

https://thumbs2.imagebam.com/14/41/22/b91bca1371437417.jpg](http://www.imagebam.com/image/b91bca1371437417)

If I remove the cable and connect direct to the antenna, I see (To my eye more interference/radio signals?)

https://thumbs2.imagebam.com/51/76/e5/04aa321371437419.jpg](http://www.imagebam.com/image/04aa321371437419)

Online reference for test system: https://opensky-network.org/receiver-profile?s=-1408233121

So my questions are;

  1. What settings should I configure on gqrx for 1090Mhz ADS-B to test properly?
  2. Hardware connection order, should the bandpass filter be before the amplifier or after?
  3. Ideally I would like to have the electronics inside and just a cable running to the antenna (yes/no?).
  4. Should I use RG174 or RG58?