Main forum to discuss RTL-SDR related topics.
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Curious to know whether there is any use for the I branch in the direct sampling mode - as far as I can tell there are no usable HF signals to be had from it...I assume because it would be behind the diplexer that splits HF away from VHF/UHF signals detected via the quadrature mode. If that is true, then I wonder if it might be possible to attach a second HF antenna after the diplexer, to be sampled via the I branch? In other words, sacrifice the VHF/UHF quadrature mode, and dedicate the dongle to direct sampling from either of two HF antennas.
What I am wondering is whether there might be a pad on the board where a second HF antenna could be attached to that connection somewhere between the tuner and the ADC chips Might need to cut the connection to the tuner, of course.
There are two test pads next to C33 and L5 (to the left of the LDO) which connect to the I-branch. But you will indeed need to disconnect the tuner by removing the two resistors next to the pads R13 and R12.