2) Reflection because of a not-resonant antenna or defective cable. If the power of the transmitter is not clear transmitted through the easySPLIT to the end of the antenna, that means it is reflected at the antenna contact, a standing wave in the device and cable to the sender will occur. Because of this overlay effects of the back and forth wave on the conductor board will appear, which can reduce the level for the detector and cause the jittering. In most cases this happens at low power but is also possible to happen at high power. Please check: Are the contacts of the antenna connector correct soldered and is the groundground of the coaxial cable correct separated from the inner wire? Please check this again at the connector which goes into the easySPLIT, at the connector which goes into the radio transceiver and at the radio transceiver itself.