This is due to RFI on the PTT line going into the display/controller unit, and can be particularly annoying when working mobile with an antenna affixed to the front windshield (like PROCOM 'Glassfix' dualbander). While working on 2m band and high power, when the microphone is held too close to the antenna, the PTT 'hangs' in TX mode when going over to RX and/or there is sometimes no modulation during TX. Icom IC-2720H (IC 2720 H IC2720H) technical specifications Icom IC-2720H (IC 2720 H IC2720H) technical specifications : Icom IC-2720H (IC 2720 H IC2720H) repeater function Icom IC-2720H (IC 2720 H IC2720H) out of band mod Icom IC-2720H (IC 2720 H IC2720H) Reducing the RFI on microphone PTT line Icom IC-2720H (IC 2720 H IC2720H) Adjustment Method by CS-2720 Cloning Software Icom IC-2720H (IC 2720 H IC2720H) crossband repeater PDF Service Manual with schematics for Icom IC-2720H (IC 2720 H IC2720H) : PDF User Manual for Icom IC-2720H (IC 2720 H IC2720H) : Programming software for Icom IC-2720H (IC 2720 H IC2720H) :
Programming interface schematics for Icom:
