KN0CK Miniature HF Upconverter Rev. 4 Now for Sale

Update: KN0CKs products are now available at

The fourth revision of the miniature HF upconverter for the RTL-SDR by KN0CK is up for sale, now that revision three has just sold out. Revision four has a 120 MHz oscillator, and is capable of receiving the 6m band.

Check out the release post over at KF7LZE’s blog, and the product sales page at the Easy-Kits store.

Receiver Opened Up


  1. phcoder

    Which tuning chip and SDR chip is it? I’m thinking of fitting an externally-accessible micro-switch on it in order to switch between 0-54 MHz and 54-1700MHz and depending on chip it would influence exact tuning range, bandwidth and linux support.

    • admin

      These are based on the RTL2832 SDR chips, and i’m not 100% sure but it looks like Rev4 uses the R820T tuner. You can always email Marty ‘KN0CK’ at martywittrock_AT_gmail_DOT_com to double check. He’s also got an upconverter DIY kit which should work with any RTL2832 device, might be easier to mod a switch with that.

    • admin

      For your first antenna as a beginner i’d recommend just making a ‘random wire’ antenna, which is literally just a random length of long wire strung up horizontally as high as you can get it (e.g. in your attic). Connect the ground to a cold water pipe or other earth (don’t use an electrical outlet though). With more experience i’d start thinking about making a magnetic loop.

      • Deric Eric

        Thanks for your response. Are there any cheap commercial magnetic loop antennas? If not, how difficult is it, to build one as a beginner?

        • admin

          I’m not sure about commercial loop antennas, but i’m guessing they would be a few hundred dollars at least.

          For building, there are a bunch of instructions on Google. If you have basic electrical and construction experience it shouldn’t be too difficult. Most tutorial use heavy duty high voltage tuning capacitors, but you won’t need a high voltage one for receive only. Here is a nice tutorial of one using a tuning cap from an old radio

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