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Input impedance at UFL-R connector.

Posted: Wed Aug 03, 2016 1:20 am
by snovotill
I request to know the design spec for input impedance expected at the U.FL connector on the circuit board.
The datasheets say that AMPORT2 impedance on the radio chip is 75 ohms, but no spec is given for the MGA-68563 LNA chip.
...and so then:
(1) I'm thinking therefore that the answer is 75 ohms but perhaps it's transformed to 50 by or is different for each input filter?
(2) The input filters would have had to be designed with a specific source impedance in mind and I wonder what that is for each band?


Re: Input impedance at UFL-R connector.

Posted: Thu Feb 02, 2017 8:27 pm
by n1kgy
Good question. Because the characteristic/design input impedance needs to be reasonably well matched between the antenna and the filter, in order for the filter to do it's job with any degree of success.