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Author Topic: Input impedance of RTL Dongle  (Read 1768 times)

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Offline jgalakTopic starter

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Input impedance of RTL Dongle
« on: January 05, 2018, 07:24:15 pm »
I have the NooElec Mini2 SDR dongle (this one: https://www.amazon.com/NooElec-NESDR-Mini-RTL2832-Antenna/dp/B00P2UOU72 ) and am trying to figure out its input impedance. 

I believe the original, TV-oriented dongles were 75 Ohm, but this one seems aimed more at experimenters and such, so maybe the changed it to 50?  Does anyone know?  Is there an easy way to check?
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Offline yl3akb

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Re: Input impedance of RTL Dongle
« Reply #1 on: January 05, 2018, 07:39:39 pm »
Hi!

By looking at board pictures of that dongle it has bare R820T tuner at frontend, with no external wideband matching components. Zin of R820 is 75 ohms. Although not explicitly shown, datasheet (https://www.rtl-sdr.com/wp-content/uploads/2013/04/R820T_datasheet-Non_R-20111130_unlocked1.pdf) has few clues that it is 75 ohm device
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Offline Yansi

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Re: Input impedance of RTL Dongle
« Reply #2 on: January 05, 2018, 09:01:25 pm »
Although not clearly specified, it is a 75ohm device.
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