An apparatus (100; 200) comprising: impedance-matching circuitry (120; 210) configured and arranged to match an impedance of a radio frequency, RF, antenna , and to communicate signals between the RF antenna and receiver circuitry (113; 222) that processes RF signals received via the RF antenna ; a transmitter (111; 220), including a combinatorial test controller, configured and arranged to transmit signals to remote devices via the RF antenna (130; 212), and to carry out a test-signal sweep of the impedance-matching circuitry (120; 210) by communicating a plurality of test signals to the impedance-matching circuitry (120; 210); sensor circuitry (114; 224, 226) configured and arranged to detect a characteristic of each of the test signals as passed through the impedance-matching circuitry (120; 210); and testing circuitry configured and arranged with the sensor circuitry to indicate compliance of the impedance-matching circuitry (120; 210) with a design specification by: for each of the test signals generated for the carrying out of a test-signal sweep, comparing the detected characteristic of the test signal to an expected characteristic for the test signal, in response to the comparisons, assessing compliance of the impedance-matching circuity (120; 210) with a design specification, and generating and transmitting an output indicative of compliance of the impedance-matching circuitry (120; 210) with the design specification. impedance-matching circuitry (120; 210) configured and arranged to match an impedance of a radio frequency, RF, antenna , and to communicate signals between the RF antenna and receiver circuitry (113; 222) that processes RF signals received via the RF antenna ; a transmitter (111; 220), including a combinatorial test controller, configured and arranged to transmit signals to remote devices via the RF antenna (130; 212), and to carry out a test-signal sweep of the impedance-matching circuitry (120; 210) by communicating a plurality of test signals to the impedance-matching circuitry (120; 210); sensor circuitry (114; 224, 226) configured and arranged to detect a characteristic of each of the test signals as passed through the impedance-matching circuitry (120; 210); and testing circuitry configured and arranged with the sensor circuitry to indicate compliance of the impedance-matching circuitry (120; 210) with a design specification by: for each of the test signals generated for the carrying out of a test-signal sweep, comparing the detected characteristic of the test signal to an expected characteristic for the test signal, in response to the comparisons, assessing compliance of the impedance-matching circuity (120; 210) with a design specification, and generating and transmitting an output indicative of compliance of the impedance-matching circuitry (120; 210) with the design specification. for each of the test signals generated for the carrying out of a test-signal sweep, comparing the detected characteristic of the test signal to an expected characteristic for the test signal, in response to the comparisons, assessing compliance of the impedance-matching circuity (120; 210) with a design specification, and generating and transmitting an output indicative of compliance of the impedance-matching circuitry (120; 210) with the design specification. <EOS>