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So I fixed a few more mistakes in the the V2 schematic for my "Ridiculously Over Engineered SWR Meter". Attached is the new schematic.
You can find the files for this, which will be released as open-source, here:
https://git.qoto.org/roes/roes-hardware/
#Ham #HamRadio #Radio #RF #EE #Electronics #ElectricalEngineering #Science #ROES
@freemo the dev board of the ad8302 has a 50 ohm shunt resistor at the inputs (R1 & R2). Is there a reason you haven't included these?
@freemo I can see you've got one on the reflected_SIG, but I can't see one on forward_SIG.
@comphys
The foward sig network winds up being at about 50 ohms equivelant.
Basically anytime you have a feedline coming in you need a resistor as a terminator that matches the feedline characteristic impedance. In the case of forward sig it is not a single resistor because i also pulled out the signal with a dc bias.
The 33 + 22 resistor gets me most of the way there in the forward sig. Then some parasitics from the forward phase shifter and envelope detector bring that down to 50ish.
@freemo ah fair enough, I was looking out for a single resistor. Yes that works.