Hi Keith / Ben, Thanks for the replies.
Yes using SMA, not RP-SMA connectors that include the pin (never any silly questions!).
Tried 2 antennas, I had it on a Diamond X50 collinear that is outside on a pole on the chimney most of the afternoon and gets me pretty good range Rx on 1090mhz for ADSB. This evening I have switched it over to the 868.3 9dbi collinear that I am 'looking after' for you Keith, but in the loft rather than outside. Obviously little to no FLARM traffic around this evening so will leave it on that antenna for tomorrow.
Stopping the software and doing a GSM scan now looks ok to my untrained eye:
Frequency = 920.000MHz..960.200MHz 2.000MHz step, 20 scans
Sampling rate = 2000000Hz = 2.000MHz
0.250sec per scan
FFT: 1024 bins, 1953.1Hz/bin, 0.256ms/slide
Found Rafael Micro R820T tuner
Exact sample rate is: 2000000.052982 Hz
RTLSDR::Open(0,940100000,2000000) => Generic RTL2832U OEM, 940.100 MHz, 2.000 Msps
RTLSDR::Gain[29] = +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 [dB]
Open(0, 940100000, 2000000) OK
Tuner crystal correction set to 0 ppm
Tuner gain set to 20.0 dB (device reports 20.0 dB)
935.200MHz: -0.8dB: +0.41 +0.17 [ppm]
935.400MHz: +3.2dB: +0.57 +0.54 +0.60 +0.54 +0.68 +0.57 [ppm]
935.800MHz: +6.1dB: +0.57 +0.72 +0.74 +0.60 +0.62 [ppm]
936.000MHz: +5.0dB: +0.41 +0.58 +0.57 +1.04 +0.51 [ppm]
936.200MHz: +3.3dB: -0.56 -0.41 -0.35 -0.41 -0.44 [ppm]
936.600MHz: +6.4dB: -0.34 -0.39 -0.36 -0.37 -0.40 [ppm]
937.000MHz: +18.6dB: -0.39 -0.36 -0.35 -0.36 -0.36 [ppm]
937.200MHz: +11.0dB: -0.39 -0.38 -0.41 -0.35 -0.43 [ppm]
937.600MHz: +16.4dB: -0.31 -0.34 -0.35 -0.27 -0.33 -0.33 [ppm]
938.000MHz: +0.1dB: +0.50 -0.30 -0.25 -0.47 [ppm]
938.600MHz: +10.1dB: -0.35 -0.39 -0.36 -0.34 -0.32 [ppm]
938.800MHz: +7.9dB: -0.27 -0.35 -0.39 -0.38 -0.30 -0.36 [ppm]
939.000MHz: +7.3dB: -0.31 -0.36 -0.36 -0.42 -0.44 [ppm]
939.400MHz: +0.3dB: -0.57 -0.37 -0.46 -0.14 -0.30 [ppm]
939.600MHz: +8.0dB: -0.26 -0.30 -0.25 -0.32 -0.27 -0.30 [ppm]
952.400MHz: +1.2dB: +0.38 +0.60 +0.33 +0.81 [ppm]
955.200MHz: +3.4dB: -0.29 -0.24 -0.35 -0.37 -0.37 -0.33 [ppm]
955.400MHz: +5.9dB: -0.30 -0.40 -0.34 -0.38 -0.29 [ppm]
955.600MHz: -1.4dB: -0.18 +0.07 [ppm]
955.800MHz: +1.5dB: -0.74 -0.47 [ppm]
956.000MHz: +13.8dB: -0.27 -0.27 -0.25 -0.24 -0.25 -0.25 [ppm]
956.400MHz: +7.4dB: -0.38 -0.52 -0.47 -0.38 -0.35 -0.40 [ppm]
956.800MHz: -0.5dB: -0.23 -0.22 -0.28 -0.36 -0.37 [ppm]
957.000MHz: +4.2dB: -0.55 -0.35 -0.35 -0.23 -0.38 [ppm]
957.400MHz: +0.8dB: -0.15 -0.28 -0.24 [ppm]
958.000MHz: +5.7dB: -0.25 -0.31 -0.30 -0.29 -0.30 -0.22 [ppm]
958.200MHz: +8.1dB: +0.55 +0.57 +0.52 +0.54 +0.54 [ppm]
958.400MHz: +1.2dB: +0.44 +0.90 +0.40 +0.48 [ppm]
958.600MHz: +5.3dB: +0.93 +0.63 +0.66 +0.62 +0.62 [ppm]
959.000MHz: +20.1dB: +0.63 +0.60 +0.58 +0.59 +0.61 +0.58 [ppm]
959.400MHz: +4.2dB: +0.62 +0.54 +0.73 +0.71 +0.74 [ppm]
959.600MHz: +7.9dB: +0.66 +0.57 +0.62 +0.58 +0.66 [ppm]
Receiver Xtal correction = 0-0.150 = -0.150 (0.299) ppm [79]
Note: when the receiver warms up the Xtal may drift 5-10ppm
Turning the gain right down still picks up some signals:
Frequency = 920.000MHz..960.200MHz 2.000MHz step, 20 scans
Sampling rate = 2000000Hz = 2.000MHz
0.250sec per scan
FFT: 1024 bins, 1953.1Hz/bin, 0.256ms/slide
Found Rafael Micro R820T tuner
Exact sample rate is: 2000000.052982 Hz
RTLSDR::Open(0,940100000,2000000) => Generic RTL2832U OEM, 940.100 MHz, 2.000 Msps
RTLSDR::Gain[29] = +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 [dB]
Open(0, 940100000, 2000000) OK
Tuner crystal correction set to 0 ppm
Tuner gain set to 20.0 dB (device reports 20.0 dB)
935.200MHz: -0.8dB: +0.41 +0.17 [ppm]
935.400MHz: +3.2dB: +0.57 +0.54 +0.60 +0.54 +0.68 +0.57 [ppm]
935.800MHz: +6.1dB: +0.57 +0.72 +0.74 +0.60 +0.62 [ppm]
936.000MHz: +5.0dB: +0.41 +0.58 +0.57 +1.04 +0.51 [ppm]
936.200MHz: +3.3dB: -0.56 -0.41 -0.35 -0.41 -0.44 [ppm]
936.600MHz: +6.4dB: -0.34 -0.39 -0.36 -0.37 -0.40 [ppm]
937.000MHz: +18.6dB: -0.39 -0.36 -0.35 -0.36 -0.36 [ppm]
937.200MHz: +11.0dB: -0.39 -0.38 -0.41 -0.35 -0.43 [ppm]
937.600MHz: +16.4dB: -0.31 -0.34 -0.35 -0.27 -0.33 -0.33 [ppm]
938.000MHz: +0.1dB: +0.50 -0.30 -0.25 -0.47 [ppm]
938.600MHz: +10.1dB: -0.35 -0.39 -0.36 -0.34 -0.32 [ppm]
938.800MHz: +7.9dB: -0.27 -0.35 -0.39 -0.38 -0.30 -0.36 [ppm]
939.000MHz: +7.3dB: -0.31 -0.36 -0.36 -0.42 -0.44 [ppm]
939.400MHz: +0.3dB: -0.57 -0.37 -0.46 -0.14 -0.30 [ppm]
939.600MHz: +8.0dB: -0.26 -0.30 -0.25 -0.32 -0.27 -0.30 [ppm]
952.400MHz: +1.2dB: +0.38 +0.60 +0.33 +0.81 [ppm]
955.200MHz: +3.4dB: -0.29 -0.24 -0.35 -0.37 -0.37 -0.33 [ppm]
955.400MHz: +5.9dB: -0.30 -0.40 -0.34 -0.38 -0.29 [ppm]
955.600MHz: -1.4dB: -0.18 +0.07 [ppm]
955.800MHz: +1.5dB: -0.74 -0.47 [ppm]
956.000MHz: +13.8dB: -0.27 -0.27 -0.25 -0.24 -0.25 -0.25 [ppm]
956.400MHz: +7.4dB: -0.38 -0.52 -0.47 -0.38 -0.35 -0.40 [ppm]
956.800MHz: -0.5dB: -0.23 -0.22 -0.28 -0.36 -0.37 [ppm]
957.000MHz: +4.2dB: -0.55 -0.35 -0.35 -0.23 -0.38 [ppm]
957.400MHz: +0.8dB: -0.15 -0.28 -0.24 [ppm]
958.000MHz: +5.7dB: -0.25 -0.31 -0.30 -0.29 -0.30 -0.22 [ppm]
958.200MHz: +8.1dB: +0.55 +0.57 +0.52 +0.54 +0.54 [ppm]
958.400MHz: +1.2dB: +0.44 +0.90 +0.40 +0.48 [ppm]
958.600MHz: +5.3dB: +0.93 +0.63 +0.66 +0.62 +0.62 [ppm]
959.000MHz: +20.1dB: +0.63 +0.60 +0.58 +0.59 +0.61 +0.58 [ppm]
959.400MHz: +4.2dB: +0.62 +0.54 +0.73 +0.71 +0.74 [ppm]
959.600MHz: +7.9dB: +0.66 +0.57 +0.62 +0.58 +0.66 [ppm]
Receiver Xtal correction = 0-0.150 = -0.150 (0.299) ppm [79]
Note: when the receiver warms up the Xtal may drift 5-10ppm
Turning the gain up does give the odd inconsistency:
939.800MHz: +12.8dB: +157.07 +164.81 [ppm]
958.800MHz: +21.4dB: -15.26 -12.18 -12.31 -16.32 [ppm]
Frequency = 920.000MHz..960.200MHz 2.000MHz step, 20 scans
Sampling rate = 2000000Hz = 2.000MHz
0.250sec per scan
FFT: 1024 bins, 1953.1Hz/bin, 0.256ms/slide
Found Rafael Micro R820T tuner
Exact sample rate is: 2000000.052982 Hz
RTLSDR::Open(0,940100000,2000000) => Generic RTL2832U OEM, 940.100 MHz, 2.000 Msps
RTLSDR::Gain[29] = +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 [dB]
Open(0, 940100000, 2000000) OK
Tuner crystal correction set to 0 ppm
Tuner gain set to 50.0 dB (device reports 50.0 dB)
923.800MHz: +14.1dB: +0.73 +0.65 +0.67 +0.69 +0.79 [ppm]
935.200MHz: +18.5dB: +0.49 +0.46 +0.54 +0.51 +0.47 [ppm]
935.400MHz: +24.9dB: +0.64 +0.63 +0.62 +0.62 +0.64 +0.62 [ppm]
935.600MHz: +17.5dB: +0.71 +0.73 +0.77 +0.81 +0.68 +0.73 [ppm]
935.800MHz: +27.4dB: +0.68 +0.69 +0.65 +0.63 +0.67 [ppm]
936.000MHz: +27.2dB: +0.63 +0.82 +0.57 +0.62 +0.69 [ppm]
936.200MHz: +24.5dB: -0.40 -0.37 -0.36 -0.34 -0.34 [ppm]
936.600MHz: +28.3dB: -0.31 -0.32 -0.31 -0.34 -0.35 [ppm]
937.000MHz: +41.0dB: -0.33 -0.34 -0.35 -0.33 -0.34 -0.34 [ppm]
937.200MHz: +33.2dB: -0.27 -0.28 -0.28 -0.25 -0.26 [ppm]
937.600MHz: +38.7dB: -0.28 -0.28 -0.28 -0.27 -0.28 [ppm]
938.000MHz: +21.0dB: -0.17 -0.38 [ppm]
938.400MHz: +15.9dB: +0.26 -0.85 [ppm]
938.600MHz: +32.2dB: -0.39 -0.36 -0.32 -0.37 -0.37 [ppm]
938.800MHz: +31.0dB: -0.31 -0.32 -0.30 -0.32 -0.31 [ppm]
939.000MHz: +28.6dB: -0.32 -0.33 -0.33 -0.24 -0.28 [ppm]
939.400MHz: +20.6dB: -0.39 -0.26 -0.51 -0.46 -0.31 -0.42 [ppm]
939.600MHz: +30.9dB: -0.26 -0.29 -0.27 -0.28 -0.27 [ppm]
939.800MHz: +12.8dB: +157.07 +164.81 [ppm]
952.400MHz: +18.5dB: +0.55 +0.58 +0.58 +0.53 +0.50 +0.55 [ppm]
955.200MHz: +23.2dB: -0.29 -0.26 -0.31 -0.29 -0.24 [ppm]
955.400MHz: +26.9dB: -0.29 -0.23 -0.24 -0.30 -0.27 [ppm]
955.600MHz: +15.3dB: -0.32 -0.64 -0.44 -0.33 -0.12 [ppm]
955.800MHz: +20.7dB: -0.76 -0.75 -0.92 -0.55 [ppm]
956.000MHz: +35.2dB: -0.28 -0.24 -0.24 -0.25 -0.24 [ppm]
956.400MHz: +28.2dB: -0.26 -0.21 -0.33 -0.31 -0.27 [ppm]
956.800MHz: +17.7dB: -0.44 -0.32 -0.28 -0.26 -0.32 [ppm]
957.000MHz: +24.8dB: -0.28 -0.31 -0.25 -0.24 -0.31 -0.27 [ppm]
957.400MHz: +19.4dB: -0.21 -0.41 -0.30 -0.26 -0.08 -0.27 [ppm]
957.600MHz: +14.3dB: -0.12 -0.17 [ppm]
957.800MHz: +14.1dB: -0.72 -0.09 [ppm]
958.000MHz: +26.4dB: -0.18 -0.25 -0.25 -0.23 -0.21 [ppm]
958.200MHz: +28.8dB: +0.57 +0.59 +0.58 +0.57 +0.59 [ppm]
958.400MHz: +21.0dB: +0.61 +0.63 +0.40 +0.57 +0.70 [ppm]
958.600MHz: +26.1dB: +0.56 +0.59 +0.66 +0.66 +0.64 +0.59 [ppm]
958.800MHz: +21.4dB: -15.26 -12.18 -12.31 -16.32 [ppm]
959.000MHz: +41.6dB: +0.67 +0.64 +0.64 +0.65 +0.64 [ppm]
959.400MHz: +25.5dB: +0.71 +0.70 +0.68 +0.69 +0.79 +0.63 [ppm]
959.600MHz: +29.2dB: +0.68 +0.67 +0.70 +0.67 +0.70 [ppm]
959.800MHz: +16.4dB: +0.79 +0.52 +0.55 [ppm]
Receiver Xtal correction = 0-0.015 = -0.015 (0.372) ppm [96]
Warning: measurements appear inconsistent:
please retry with better initial estimate or with lower gain to reduce distortions
Note: when the receiver warms up the Xtal may drift 5-10ppm