SDR Dongle - Assistance Requested

Discussion in 'General Technical Questions and Answers' started by WB4IME, Dec 30, 2017.

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  1. WB4IME

    WB4IME Ham Member QRZ Page

    Received a RTL-SDR v3 for Christmas.

    I am running WIN 10. Software and drivers installed/loaded without incident.
    Software runs great on my system - no hangs, no crashes, nothing ... all good to go.

    Situation :
    Tried listening to 40 mtrs today around 2 pm (EST - I am located in western NC). Nothing to hear. As far
    as SDR was concerned the band was dead. Later in the day ( 6 pm ) lots of signals but not very strong.

    #1 Presently using a 75 meter long wire dipole for antenna. Product recommends using a Discone Antenna. They also sell a small extendable whip type antenna configured in a V Configuration that can be mounted inside/outside. How much improvement would I experience using one of these other antennas ?

    #2 Researching the internet I learn there are "upconverters" that allow HF frequencies to be 'converted over' to the VHF spectrum so the SDR dongle can better process them ? (Hope I have that correct). How much improvement would I see in the signals, volume, sensitivity, etc if I obtained an up converter ? Does it make that much of a difference ?

    #3 I am running a Kenwood TS-450S. Have not been able to locate any websites that describe how this specific
    SDR dongle and software can be utilized in conjunction with the 450. Do you know of any websites or have any experience in this regard ?

    Any assistance you may provide is deeply appreciated. Tnx !

  2. W5DXP

    W5DXP Ham Member QRZ Page

    You will get more responses on the "Working Different Modes" forum. Your dongle is probably a receive only device covering 24MHz-1+GHz and doesn't require the TS-450S. I bought an upconverter for mine that covers LF and HF. Here's the best book and web page of which I am aware.

    The Hobbyist's Guide to the RTL-SDR: Really Cheap Software Defined Radio
  3. WB4IME

    WB4IME Ham Member QRZ Page

    It is receive only ... yes. Thank you for the tip "Working Different Modes" forum.
  4. VA3VF

    VA3VF Guest

    Sounds like you are using direct sampling (Q branch), bad idea. Some people claim it works fine, but my experience is different. The manufacturer itself is careful to call it an experimental mode. The upconverter is a must for decent performance. That said, I can say with experience, that once you add the upconverter, then a BCB and/or FM filters, pigtail adapters, etc. you'll have spent a lot more than the new RSP1A SDR, a much better SDR.

    I played with RTL dongles of many types, still have at least 5 or 6. Two upconverters, the NooElec and Spyverter. Finally decided to buy the RSP1A. The RTL dongles will be used for VHF+, but below that, the RSP1A rules. I'm now thinking about getting the new AirSpy HF+ SDR, which appear to be not only better than the RSP1A, but some other high priced SDRs as well.

    Regarding antennas. The one you use, longwire, requires a 9:1 impedance matching transformer. I use this one:

    The discone and whip type antennas are useless for HF.

    Regarding the TS-450S, I guess you want to add waterfall capabilities to it. That can be as easy as connecting the dongle to an IF port, if available, and as difficult as requiring internal mods. Search the web for you particular model, and see how it can be done.

    The RTL dongles are an incredible SDR learning platform, and can be used in a lot of situations very satisfactorily. Unfortunately, HF is not one of them, if taken seriously.
  5. KS2G

    KS2G Subscriber QRZ Page


    You don't say which software you're using.
    If you used the RTL-SDR quick start instructions, probably SDR# (pronounced SDR-sharp).
    If that's the case, check the Configure panel to see if you've increased the RF Gain -- which is set to zero by default.

    Not withstanding the above post by VA3VF, I'm using direct sampling to receive HF on the RTL-SDR just fine.
    Using my trap dipole on 40 and 80 meters, it pulls in pretty much everything I hear on my Kenwood TS-590S.

    You can set-up the RTL-SDR as a "band scope" for your TS-450S but it requires some pricey external hardware to have the rig and the dongle share the same antenna. For example a DX Engineering RTR-2 Modular Receive-Transmit Interface along with a DXE-RSC-2 antenna splitter/combiner and a DXE-RG-5000 RF limiter.
  6. G0GSR

    G0GSR Ham Member QRZ Page

    My RTL dongle is EXTREMELY insensitive in direct sampling mode. (Below 24MHz)
    Only good for monitoring your local transmission.
  7. NC4AB

    NC4AB XML Subscriber QRZ Page

    I also have the RTL-SDR v3, and I assume you are running SDR# software. Mine works great for monitoring above 30 MHz, but is very deaf below 30 MHz . I have played around with it on HF and tried it in normal "Quadrature Sampling" mode and also in "Direct sampling Q branch" mode without much success.

    The antenna recommendations being made are more for 30 mhz and upwards where the dongle is designed to operate, and would not be any better than your long wire.

    No experience with the frequency converters.

    Good luck with the SDR dongle, the DSD software works great for decoding digital transmissions.
  8. WB4IME

    WB4IME Ham Member QRZ Page

    Thank all for answering. Any additional suggestions are welcomed.
    The unit does operate fairly well at night, when the conditions seem a little better. I've adjusted the the different sampling modes but the mfg recommended settings seem to work best.

    Any other suggestions for use with my TS-450 would be great. I'll look into those suggestions by KS2G.
  9. WB4IME

    WB4IME Ham Member QRZ Page

    This website : sells kits or completed boards for installation in the TS-450.
    However the owner recently passed and business has been suspended.

    Do you know of any other resource that provides similar/same service ?

    Any assistance you may provide is deeply appreciated. Tnx !

  10. W5DXP

    W5DXP Ham Member QRZ Page

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