Periodic interruptions on waterfall

SatNOGS
,
1

Good Day Everyone,

I’ve gotten my station up and running, however, I seem to be encountering an issue with my recordings. There is a periodic and consistent bar where there’s almost no received signal coming into the radio every ~60 seconds. The surrounding frequencies have been checked, but there appears to be no strong signal that corresponds to the ~60 second period. Is there an internal setting that could be causing the RTL-SDR Blog V4 to shut down or reduce gain drastically? Station 3581 near me has also experienced this same issue, but is running an RTL-SDR Blog V3.

Thank you so much for your assistance. Below is an example w/ metadata:

Waterfall - Obs 9812988
Waterfall - Obs 9812988823×1603 88.3 KB

radio: {
    name: "gr-satnogs",
    version: "v2.3-compat-xxx-v2.3.5.0",
    parameters: {
        soapy-rx-device: "driver=rtlsdr",
        samp-rate-rx: "2.048e6",
        rx-freq: "137620000",
        file-path: "/tmp/.satnogs/data/receiving_satnogs_9812988_2024-07-08T23-37-04.out",
        waterfall-file-path: "/tmp/.satnogs/data/receiving_waterfall_9812988_2024-07-08T23-37-04.dat",
        decoded-data-file-path: "/tmp/.satnogs/data/receiving_data_9812988_2024-07-08T23-37-04.png",
        doppler-correction-per-sec: null,
        lo-offset: null,
        ppm: null,
        rigctl-port: "4532",
        gain-mode: "Overall",
        gain: "49.6",
        antenna: "RX",
        dev-args: null,
        stream-args: null,
        tune-args: null,
        other-settings: null,
        dc-removal: null,
        bb-freq: null,
        bw: null,
        enable-iq-dump: "0",
        iq-file-path: null,
        udp-dump-host: null,
        udp-dump-port: 57356,
        wpm: null,
        baudrate: null,
        framing: null
    }
},
latitude: 45.96299067991878,
longitude: -66.62266471226759,
elevation: 12,
frequency: 137620000
2

A bit hard to tell. If you schedule a satellite in the 145 MHz amateur range does that also show the same interruptions ? Does the “nearby station” with the same problem have that on the same satellite observation or does this happen on all frequencies ?

Can you disable the groundstation and run something like SDR software on the same hardware (rtl-tcp, spyserver ?) to live view the results of your SDR / antenna setup ? Is there an (powered) LNA active ?

Ben

3

Possibly desense from a strong nearby emitter?

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