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I'm looking for a way to measure noise signals (probably MCU harmonics) that affect the performance of my GPS receiver (Ubox sam-m8q-0-10.) Can anyone point me to the right direction?

I own a spectrum analyzer up to 3 GHz, a set of magnetic field + electric field probes. Can anyone suggest documentation on how to use my hardware in order to find the noise?

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  • \$\begingroup\$ do you have a RF signal generator? if you have one, you can measure a higher power level signal (-130 or -100 dB) and observe the final output of your circuit till the LNA. -170 dB is challenging i feel. \$\endgroup\$
    – User323693
    Commented Feb 24, 2020 at 7:53
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    \$\begingroup\$ Is the -170 dB with reference to watts or milli watts or volts or amps or sub variants? "dB" without some extra information is meaningless as an absolute level. \$\endgroup\$
    – Andy aka
    Commented Feb 24, 2020 at 9:22
  • \$\begingroup\$ Hello @User323693 . I don't have an RF generator. I have some LNAs though. I have thought of amplifying the signal in order to be able to see it with my spectrum but because I'm kind of inexperienced I have to study before using the HW in order to avoid destroying something. \$\endgroup\$
    – k.ifantidis
    Commented Feb 24, 2020 at 12:05
  • \$\begingroup\$ Hello @Andyaka . I would like to measure the electric and magnetic field with my spectrum analyzer. My analyzer is in dBuV if I'm not mistaken. I would like to find which is the "noisy" part and then find a way to reduce it's electromagnetic radiation. \$\endgroup\$
    – k.ifantidis
    Commented Feb 24, 2020 at 12:09
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    \$\begingroup\$ -174dBm is the thermal noise floor for a 1Hz bandwidth at 300K (27C). Although there are ways to measure signals below that, I doubt your spectrum analyser can do so. \$\endgroup\$
    – Peter Smith
    Commented Mar 19, 2023 at 15:43

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I think -130 dBm is the level received on the Earth's surface and it is very low level. Moreover, the GPS signal is DSSS which cannot be display on the spectrum analyzer directly because it is always below the noise floor.

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    \$\begingroup\$ It is true that the GNSS signal is spread spectrum and below the noise floor, but the questioner is looking to measure the noise signal not the GNSS signal. \$\endgroup\$
    – colintd
    Commented Aug 26, 2023 at 8:12
  • \$\begingroup\$ Is it always below the thermal noise floor, or just on weak signal conditions we can not see that>? \$\endgroup\$
    – mohammadsdtmnd
    Commented Nov 6 at 15:10

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