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RTL_SDR missing components?

Posted: Fri Jun 17, 2016 7:02 pm
by DamianL
I recently bought the RTL_SDR from Amazon and while performing the Bias Tee mod I saw that there were some components missing.

Missing: C6, R3, R6, C27, C28

Special Case: C23


The list of components above was missing, for the special case (C23) it is the pad closest to the 2 pads needed for the bias tee mod so I can see accidentally knocking that off.

Attached is my unit.

The unit was functionally decoding FM, with GNURadio, before I performed the Bias tee mod.

Are units being shipped without these components? are they needed?

Does anyone have schematics that have the various resistor and capacitor values on it?

Thanks

Re: RTL_SDR missing components?

Posted: Mon Jun 20, 2016 8:45 am
by rtlsdrblog
Those components were for the IR LED and LED light, but we've removed them on ours as they are not needed, and have no purpose especially since we use a metal case.

C23 can be 10nF or larger. I wouldn't operate the dongle as you have, with C23 missing. The purpose of C23 is to block the 5V bias tee DC entering the ESD protection diode. If you run the dongle like this the BAV99 ESD diode could get damaged, or the bias tee might not work properly as a lot of voltage might be getting shorted to ground.