The area between a transceiver's output contacts and the resonating antenna is usually specified to be fifty ohm impedence. The variety of active and passive parts (inductors, capacitors, switches) tune the circuits to a target frequency. Sendcomm targets users of approximately 900 MHz ISM bands, and testing the radio path on three frequencies (868, 915, 923) results in good radio accuracy.
Radio Path Calibration
The Sendcomm radio path is calibrated to transmit and receive on several (approximately) 900 MHz bands.