VK2RK
Active member
(This is a concept design as such is theoretical, final design will include any other solutions as required)
When you have two radios and wish to use one microphone.
I decided to design such a device, in my limited desk space this will allow me to use my studio microphone and PTT control on the selected radio.
The design uses a CD4066 this device consists of four independently controlled switches that will handle both a DC voltage and AC signals. The PTT current from an ICOM radio I measured to be 1.5 mA the CD4066 will sink 10 mA so this is well within the ability of the device to handle the PTT current.
The device is powered from the radio 8 Volt source present on the microphone socket, note that two diodes are used to source from either or both radios isolating one radio from the other. This in case one of the radios is not turned on, the switcher will still operate.
The CD4066 operation is straightforward, when a high is applied to the Control the switch is closed so if Ctrl A is high switch A is closed and so on.
with this I can steer the Audio and PTT signal from one radio to the other.
The diodes on the PTT lines are there to protect the CD4066 in case of switching inductive loads on the PTT
I may need to apply some RF suppression to stop any RF getting into the circuit.
This circuit will work on other brand radios as long as the PTT current is less that 10 mA.
When you have two radios and wish to use one microphone.
I decided to design such a device, in my limited desk space this will allow me to use my studio microphone and PTT control on the selected radio.
The design uses a CD4066 this device consists of four independently controlled switches that will handle both a DC voltage and AC signals. The PTT current from an ICOM radio I measured to be 1.5 mA the CD4066 will sink 10 mA so this is well within the ability of the device to handle the PTT current.
The device is powered from the radio 8 Volt source present on the microphone socket, note that two diodes are used to source from either or both radios isolating one radio from the other. This in case one of the radios is not turned on, the switcher will still operate.
The CD4066 operation is straightforward, when a high is applied to the Control the switch is closed so if Ctrl A is high switch A is closed and so on.
with this I can steer the Audio and PTT signal from one radio to the other.
The diodes on the PTT lines are there to protect the CD4066 in case of switching inductive loads on the PTT
I may need to apply some RF suppression to stop any RF getting into the circuit.
This circuit will work on other brand radios as long as the PTT current is less that 10 mA.