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  • #11498 Reply

    Hello, can anyone advise me how to shortwave with this USB SDR receiver? [url]https://www.ebay.com/itm/RTL-SDR-Blog-V3-RTL2832U-1PPM-TCXO-HF-BiasT-SMA-Software-Defined-Radio/272411458376?epid = 1649791159&hash=item3f6cfcfb48:g:H1cAAOSwLMFb~9Qy:rk:2:pf:0
    Unlike the FT897, it is deaf for the same HF antenna.
    This is acceptable at VHF VHF.
    Some adjustments are needed?

    Leo OM2ALB

    #15070 Reply

    He looked at the band in which SDR works?

    #15071 Reply

    Additional equipment needs to be purchased, so-called up-converter, which will also allow the reception of radio signals in the HF band. Most such SDR receivers operate from 24 MHz higher …. For example, try the page https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/ see paragraph Recommended accessories from other sellers / Upconverters

    #15072 Reply

    The key in question from OM2ALB is rtl-sdr.com V3.

    In normal mode, the R820T2 input filter ends “chip tuner” at the lower limit around 25MHz, although 3MHz reception can also be set, but the input filter here attenuates a few tens of dB, therefore “hluchota”.

    This particular keychain rtl-sdr V3 has been modified by the manufacturer, among other “HF Direct Sampling Mode” the input connector is switched via adaptation directly to the input of the RTL2832U chip and can be listened to 0-14MHz in the I-branch for direct sampling and 14-28MHz in the Q-branch. For reception below 25MHz it is necessary in “drivers” set the correct band.
    Details: https://www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/

    There are several problems, This keychain has a very limited dynamic range, 48dB is indicated, in HF Direct Sampling Mode the whole band 0-14MHz is processed without any filter and only one strong signal is enough and it is necessary to set the gain for this signal, sw decimation will help a bit, but without a proper preselector, this boy is sometimes at the level of a toy. Example, listening in the band 40m in the evening, AM radio led them in power 9+40, then at the reception in the hamband we leave 8dB under S9, therefore, we will count stations stronger than S8… AM stations below 1.5MHz will also work.
    Another problem is parasitic signals when used in the 14-28MHz band in the Q-branch, where you can hear strong signals from the 0-14MHz band (alias).

    During the day and when using a bandpass filter, it can also be used in HF Direct Sampling Mode for medium-strong signals. I've tried it since 80 after 30m using a simple coax filter (quarter stump for 80m) on multiband deltaloope and sw spyserver for sdr sharp.
    For this particular SDR guy is the best very “spicy” antena typu magnetic loop, which is itself a preselector 😉

    Using the upconverter will improve the situation, the boy is better for me “selectivity” thanks to the input filter, but miracles do not have to wait, this filter is ratan on wide DAB and DVBT signals, not on the strand of the strand, but on the key “evil” even a very strong 5MHz signal led (if the upconverter can handle it). But instead of paying for an upconverter (on rtl-sdr for 50USD) and $ 20 per keychain, it's better to look for something better, like a toy (suitable for SDR), for example https://www.sdrplay.com/rsp1a/ for approx. 110USD, ktora to ma BPF, displays the 10MHz band, ma 14b translator (rtl ma 8b)…
    The ratio is the best possible reception / price in this segment of USB receivers for HF + 2m has current https://airspy.com/airspy-hf-plus/ . (No 6m, 4m 70cm pasmo)

    But so that I don't just chase the RTL-SDR boyfriend, SDR is sufficient to play and get acquainted, after the addition of BPF, usable reception is also possible, if one knows, what can be expected from 50dB dynamics within the bandwidth bandwidth and how to play with profit. An example of such a solution can be tried out using SDR sharp (SDR #) at sdr:// List here https://sites.google.com/site/om1aeg/websdr

    #15073 Reply

    Thank you all for your advice and Tone for explaining the issue in detail.
    I'm starting with SDR and that's why I bought something cheaper to touch. Right with the magnetic loop antenna on 3,5 – 7,5 MHz I tried and compared it on HF. So I will follow your advice, I just have to study it when I have time 😉
    Leo OM2ALB

    #15074 Reply

    So I finally had time to study this issue a bit.
    And it worked. I finally used HDSDR software, because SDR # could not find my keychain even after installing the drivers.
    After switching to the Q branch (you must first press the stopwatch) my keychain
    listens to KV even without BPF and preselector.
    Antenna homemade MLA diameter 80cm and range 3 – 7,8MHz.

    #15075 Reply

    So the lone MLA is BPF and the preselector 🙂 80cm smycka be “normal” listen to 80m par tens of kHz.
    And use mas “driver” installed and it works for you under HDSDR, so for “separation” RTLSDR in SDR # must use the files contained in “zipe” SDR#, after unpacking to the directory, where windows does not need to be accessed as “admin” should be clicked on “install-rtlsdr.bat” (run as administrator) and it should work (SDR # will download the necessary files for the RTLSDR keychain to “of his” address book). The procedure is listed here: https://www.rtl-sdr.com/rtl-sdr-quick-start-guide/

    #15076 Reply

    Right now, I've tried it on “cyst” Win 8.1 installation, manual driver installation from https://zadig.akeo.ie/, then click on “”install-rtlsdr.bat” in the directory with SDR # and works at first 🙂

    #15077 Reply

    well thank you, I try.

    PS: On android – SDR Touch – me “keychain” went without problems from the beginning, I just had to buy a key to show me the spectrum, and this control is not as convenient as via a laptop. And I didn't know before, that the I-branch and Q-branch must be switched to KV. However, SDR Touch also includes this function.

    #18736 Reply

    Repair of RTL SDR receiver BA5SBA

    If you bought someone from AliExpress or other online stores, the receiver: 100KHz-1.7GHz RTL-SDR Upconverter USB Receiver N300U and KV range does not work for you on my website at the link: https://www.qsl.net/om3cug/ba5sba/rtl_sdr_rx_ba5sba.htm you will find instructions on how to fix it. This is a HW factory error probably with a large series of these receivers!


    73 Igor OM3CUG

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