Chinese RTL-SDR Receiver Kit

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SKD-Kit SDR-ReadytoGo

Cost: $26

Kit Contents:

Bag of parts, RTL SB Stick, Enclosure.

No instructions were included, however, the seller gave a link to a download area for the instructions which included a copy of SDR#.


  • The Assembly instructions were in terrible English, the detailed pictures made up for it.  Hint: Magnify the word document 500x to see the little wires!
  • Be prepared to use magnifiers, microscopes, extra small soldering tips, etc.  I used a USB microscope and still had problems!
  • The first step wants to cut and drill all the enclosure holes but the enclosure received had them already done.
  • Before starting I used HDSDR to Test Dongle First – just to make sure it was good before continuing.
  • The USB connector on the RTL-USB board was destroying during removal.  For some reason getting the solder off without damaging nearby parts seemed to be a challenge.  So the solution was to open the shield along the botton slit, peel back the shield and carefully remove one end of the ground at a time.  After this the shield and plastic interior slides off leaving 4 long wires which are then easily removed and cleaned out.  Tip: I use a quilting needle to clean the holes.
  • Solder the USB dongle board into the carrier board BEFORE attaching the toroid, this allowed putting the board into a PCB vise and avoid damaging the small components near the edge of the RTL-USB board.  This also made it easier to measure and trim the toroid wires.
  • Not included were wires to attach the RTL-USB board onto the carrier board.  I used excess resistor/capacitor lead clippings for the 6 connections along with bridging the ground connections.  Getting the leads on the 2 SMD components was a challenge but not nearly as tough as the toroid wires.  You do save the clippings, dont’ you?
  • Toroid:
    • The Trifilar Wires and toroid itself is extremely small but fortunately each wire had it’s own color which made it easier to identify.  Tip: Print the last page of the manual which shows the toroid schematic.  Then holding the toroid horizontally identify write down each color on the schematic such as Blue-Top, Blue-Bottom, Red-Top…….
    • Attaching the wires onto to SMD IC was a brutaly painfull process.  Out of the 6 hours build time, 4 was spent dealing with the toroid and soldering wires.  What was worse is that my finest soldering tip was still a too big to fit between the IC and the capacitors next to them.  I ended up using some silver SMT  solder paste and my SMD reflow gun to finally get the darned things on.
  • The remaining assembly of the final parts went as planned.
SDR-Small-Wires1RTL-SDR Construction SDR-Small-Wires2Closeup of Toroid Wires

This was my smallest Soldering tip!!

Operation & Comments:

  • HPSDR:
    • Worked straight out of the box  but had issues……
    • Remember to change the RTL USB setting to Direct Sampling Q input or it won’t work on the HF area.
    • Low  sensitivity, what I was receiving on my IC-725 as S9+20 was coming out about S3 on the SDR software.
    • CHU Canada can be heard over a 3MHZ tuning region.
    • USB mode seemed even less sensitive than LSB.  CW had a constant tone which could not be removed.  AM had a heterodyne and needed to be zero beat.
    • Could no longer make VHF (FM Radio) work.
  • Challenge getting SDR# to work but found I forgot to run install-rtlsdr.bat.  Once that ran it worked great.  Use the RTL-SDR (USB) for the source and again make sure you are using the Q direct sampling setting.
    • Sensitivy is much better but still a little low compared to the IC-725.  But what do you want with a $26 radio?
    • Heard SSB voice and shortwave broadcasts in the 21.0xx area as well as a USB weather station on 28.446MHz.  I have heard comments of images above 14MHz.   Heard signals up to 12M and down to 80M.  10 (11) & 160M signals were not heard and most AM radio stations were barely heard.
    • VHF works but you need to stop the radio, change from Q back to Quadriture sampling, then re-start the radio.  Also change from the HF to the VHF antenna connection.
  • Moved the toroid wires to the I side (pins 1&2) of the SMD IC which did not impact sensitivity or performance.  Still a challenge to solder but MUCH easier than pins 4&5 behind those other parts!
  • Tried to use sdr-radio software using the rcp_tcp service (rtl_tcp direct_samp=1), I could see the software changing the frequency, etc via the rtl_tcp monitor windows and received noise.  Eventually I found the 40M band around 6.7-6.8MHz but could not find any place for an offset.  Signals were also barely audible.  FM Broadcast (rtl_tcp – no switches) seemed to work OK.
  • The winner for best signals was SDR#.
  • Final Comments:  For $26 it’s hard to beat for a cheap HF SDR radio.  Would I build it again and play with those little wires on the SMD IC?  Heck NO!  Once was enough.
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