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RX difference between SDR and a hardware XCVR

Discussion in 'Software Defined Radio (SDR)' started by N4RNR, Mar 27, 2019.

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  1. N4RNR

    N4RNR Ham Member QRZ Page

    In theory, if you were to plug the same antenna into a hardware XCVR or an SDR, should the reception be of approximately the same quality? IOW, all of the power that the XCVR is used for TX I'm assuming, so does it have any RX advantages over the SDR?
  2. WA7ARK

    WA7ARK Ham Member QRZ Page

    The SDR-based radio I have now (IC7300) runs circles around any analog radio I previously owned (Various Heathkits, R-390, Drake2B, TS-50, TS-120, 130, 430, 440, TS-850, FT-950)
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Even SDRs have linear stages doing a lot of the actual heavy lifting.

    The mike preamp is linear; the transmitter RF output stages are linear. The bandswitched power amplifier filtering designs should all be the same, etc.

    Rigs using DSP as many do for the past 20 years (and it's become better and better over time) have a lot of flexibility that has eliminated the need for some hardware, and enhanced the way the hardware works. SDRs can be even more flexible as software updates can add features, enhance operation, or fix bugs without having to lift a screwdriver, let alone a soldering iron!:)
  4. SM0AOM

    SM0AOM Ham Member QRZ Page

    The SDR has a somewhat different strong-signal behaviour compared to the analogue receiver

    An SDR has a quite well-defined overload threshold,while the analogue RX has a more gradual degradation.

    This does however come at a price, the first and second adjacent channel rejection in the SDR can be made much better due to the much lower influence of oscillator noise, and the possibility of creating near ideal filter shapes.

    It is however seldom that this superior adjacent channel performance of the SDR can be used in practice.

  5. W1VT

    W1VT Ham Member QRZ Page

    Radios with good crystal filters and high dynamic range mixers may still be superior if you have to share the ham bands with other amateur stations.
    I live 2 miles or 3km from W1AW--their signals can make it hard to hear DX stations, such as XX9D on 3580 kHz.
    Fortunately I was able to adjust the filter on my radio just in time to hear the FT8 F/H come back to me! And I got lucky with a gray line propagation peak.
  6. SM0AOM

    SM0AOM Ham Member QRZ Page

    If you have to share the bands with many other amateur stations in close vicinity having "average" or worse in-band spectral properties, no receiving technology in the world can save you...

  7. KS2G

    KS2G Subscriber QRZ Page

    I don't know about theory, but in practice the SDRplay RSP-1a that I uses as a "second receiver bandscope" with my Kenwood TS-590S are pretty much the same in "casual" operating, but the '590 performs a bit better under contest conditions.
  8. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    Hey man!

    Don't forget that Radios usually have bandpass filters, which remove other potentially strong signals that could overwhelm your SDR.

    Putting under perspective the ubiquitous RTL SDRs, the radio is something that was actually built for a purpose: Listening and transmitting voice or signals on a given frequency/band.
    Realtek SDRs chips were projected originally as Digital TV receivers, and someone just out of curiosity found that it could tune other signals with that chipset.

    If you are talking about speciality hardware, like USRP, HackRF, KiwiSDR, etc, your mileage may vary.

    73s de PY2RAF.
  9. N5SMO

    N5SMO Premium Subscriber QRZ Page

  10. KF5NAJ

    KF5NAJ Ham Member QRZ Page

    What do the Sherwood spec mean to the average Ham, which spec determines the ability to hear a weak signal

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