Assembling the Chinese RTL-SDR Direct Sampling Kit
A few months ago we posted about a Chinese individual (BA5SBA) who had begun selling RTL-SDR dongle kits for receiving HF frequencies. Back then it wasn’t entirely clear what these kits were or where they came from. Now over on Reddit, poster SidJenkins has bought one of these kits and assembled it. He has uploaded images of the construction which can be found here and the Reddit discussion can be found here. The kit is essentially an RTL-SDR extension PCB board that aids in building a direct sampling RTL-SDR with good performance by including filters and impedance matching.
SidJenkins notes that the kit came with no instructions, so he used this thread in Chinese (use Google translate) to help put the kit together.
I am at the assembly stage of making the RF Impedance transformer. The Amazon.de seller included wire, but without differing colors. I am so glad I found this website.
… It’s because no one noticed, that’s the 22μF connected anywhere on the coil side in any existing description on the Internet? I can at least at any point and in any description of what to read or seen in pictures …
BA5SBA’s original instructions for the 2015.01.29 version, in “english” PDF.
https://yo2mab.wordpress.com/2015/03/24/kits-100khz-1-7ghz-uv-hf-rtl-sdr-usb-tuner-receiver-r820t8232-cw-fm/
What is the Jumper A and P for?
In the A position, it is supposed to provide 5V power for an active antenna amplifier.
I received assembled version from China. But I’m not sure if it works correctly. Can some one tell what is that jumper in top-right corner? I have mine connected from center to “P”. I could not receive shortwave, I think 🙂
I put together a summary from information collected here and there on the internet – including this blog.
Hopefully it will save some folks a bit of time when they get started on this kit
https://docs.google.com/document/d/1P0H1-DmGuAe7MbtWZBZ_gjzIg6b_midW5xSMiw8QXd4/pub
I notice on mine there is also a SMD mounted LED as well as an original LED.
Is this SMD LED Polarity dependant like a normal LED is? or does it not matter? the thing is so small and even at 500X magnification I cant see any + or – markings
This is just a open letter to the people that are relaying out the pc board for the RTL-SDR radio .
Why not just make a dongle that goes from 0 hz to 30 mhz going through the t820 turner , and I don’t mean by putting a up converter on the same broad like I see when I am surfing the net . I would think it would be better to just put in the right Crystal Clock Oscillator for the lower hz .
I would think that you would still need a RF amp and preselect the HF part of it .