Perhaps we should have an SDR forum on QRZ.com?

Discussion in 'Ham Radio Discussions' started by W4RAV, May 13, 2014.

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  1. KA9MOT

    KA9MOT Ham Member QRZ Page


    A little touch (and I mean little!) of solder on the center pin and a .125 octagon crimp for the barrel with some heat shrink for strain relief. I use Amphenol MCX connectors. Amphenol specifies .001 crimp for the center pin, but that is unobtainium so I solder it instead.
     
  2. W6RZ

    W6RZ Ham Member QRZ Page

    bladeRF (http://nuand.com) 24 MHz waterfall showing electricity and water smart meters.

    [​IMG]
     
  3. W4RAV

    W4RAV Ham Member QRZ Page

    $(KGrHqN,!ncFBZ0+euhNBRrDtWJo5Q~~60_57[1].JPG

    Finally got around to it. Sorta. Haven't found a male MCX to male PL259 "Y" splitter. I think that's right. Looking for something like the above image, but to go between two dongles and a PL259 A/B switch. Which I plan on changing out some day to something like the Diamond CX210 N-Type DC-3000MHz switch.

    My antenna is an "N" type connector, which on VHF+ will make a difference, but haven't got around to changing out the coax, switch, etc. yet. Using N-to-PL259 adapters, which introduces even more loss. 8/
     
  4. KB1YFD

    KB1YFD Ham Member QRZ Page

    [​IMG]Here is a little project I've been working on. I use the dongle in direct mode. Great RX from DC to 15 MHz.

    Hardware:
    http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

    Hardware mods: (I removed the caps and connected to the RTL2832U Pins 1 & 2, works better)
    http://www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/

    Here is the pic of my hardware mod. It's very small smt stuff. Maybe 10X glasses or a young fella to do the soldering.

    1) Pull cover with fingernails, it will pull apart and snap together when done.

    2) Remove 3 small SMT capacitors
    A) C13 near antenna connector and D6
    B) C33 & C34 near pin 1 of the RTL2832U chip

    3) connect a pair of small wires (AWG 30) to the cap pads that connect to pins 1 & 2 of the RTL2832U chip.

    4) Run the wires over to the antenna connector. One for the shell and the other connects to D6 (See pic)

    5) I use a MCX to BNC adaptor cable to connect to my antenna: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

    Go to http://sdrsharp.com/downloads/sdr-install.zip
    Download the code and unzip it.

    A step by step installation instructions can be found in the community website:
    http://rtlsdr.org/softwarewindows
    http://rtlsdr.org/softwarelinux
    To get started with SDR# you may be interested by the excellent document from Henry (N2VFL) :
    http://www.atouk.com/wordpress/?p=153



    Plug the dongle into a USB port and wait for windows to say "Found new hardware" when it fails to find a driver, cancel it!

    Follow the instructions located here: http://rtlsdr.org/softwarewindows

    Have fun and enjoy. It works best at 15 MHz and below. I got WWVB at 60 KHz the other night.

    Best, John KB1YFD
     
  5. W4RAV

    W4RAV Ham Member QRZ Page

    I considered a bladeRF, a very fine SDR, but I'd miss everything below 300mhz with it. Unless I spend another $200 for the converter. And of course, $400+ is a lot more than what an RTL-SDR costs.

    Granted, it's a better SDR, but I can't imagine it's 20x (per the price) better. But at least you can transmit with it!

    blade_new[1].png
     
  6. W4RAV

    W4RAV Ham Member QRZ Page

    You pretty much lost me there. No interest in working on gear, 'specially since my time is more valuable than the cost of buying a $40 converter.

    Another thread on the mod, for those more inclined:
    http://www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/

    Me, I'm a pure "appliance operator". A good one mind you, but no desire to see inside what I operate. I'd rather do what I do best and leave those projects to those more skilled than I! ;)
     
  7. W6RZ

    W6RZ Ham Member QRZ Page

    It's not for everyone, but I've had a a lot of fun with it for transmitting digital amateur televison (DATV). We (meaning the bladeRF community) have four digital TV formats working on bladeRF, ATSC, DVB-T, DVB-S and cable TV 64-QAM.
     
  8. W4RAV

    W4RAV Ham Member QRZ Page

  9. W4RAV

    W4RAV Ham Member QRZ Page

  10. KA9MOT

    KA9MOT Ham Member QRZ Page

    You might want to consider using a transformer (roll your own, it's easy), to tame that puppy and keep the unwanted crap out (It won't overload as much as it does).
     
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