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I am combining the layout for two PCBs, one with an RF output SMA jack, and the other with an input jack, into a single PCB.

We were originally connecting the separate boards with a ~3" segment of SMA coax cable.

In the combined layout, can I simply join the output and input together with a short where the SMA jacks were previously, or are there other considerations to make at this junction?

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  • \$\begingroup\$ The frequency isn't mentioned. Is it possible that the 3 inches of coax acted as a delay line? Phasing? Intentional attenuation? Assuming that both traces are 50 ohms means that a short wouldn't cause an impedance problem, but how will testing be affected? In other words, if board A is a local oscillator and board B is a mixer, how will you be able to test the mixer portion of the circuit independently of the LO? \$\endgroup\$ – Buck Calabro Feb 28 '14 at 16:40
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It would probably be ok. The loss in the connectors and the cable is probably negligible. I would make sure that the impedance of the PCB trace is the same as the connectors and cable to avoid mismatch between in- and output of the circuits.

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