microphone switching

[Flump]

i have two ham radio trancievers and want to use one microphone
for both of them so i need to make a switch up to switch the
wires from the mic to one or the other radio but not both at the same time.

radio a
screen
audio
tx
rx

radio b
screen
audio
tx

on "radio a" rx and screen need to be linked in recieve mode
or there is no speaker audio, this is normally done with a
push to talk switch in the microphone.

the mic i am going to use has a ptt switch that does rx/screen switching
so that is fine if the selector switch is set for the mic to go to "radio a"
but i would like that radio to also recieve when the mic is switched to "radio b"


been trying to workout a way of doing all this at the same time and not really
getting anywhere

can anyone sugest any ideas for this ?

[David_AVD]

Do you want "radio a" to be in receive mode, even when "radio b" is transmitting (and visa versa) ?

[Flump]

yes David i do

they are on different bands which i monitor at the same time

[David_AVD]

You should be able do that with either a multi-pole switch or some relays.

Arrange it so the Rx contact for "radio a" is shorted to the screen when the selector switch is in the "radio b" position and visa versa.

The switching for the tx and mic wiring will be straightforward.

[Flump]

how about one of these
http://www.ebay.co.uk/itm/5V-8-Channel-Electronic-Relay-Module-for-Arduino-PIC-PLC-AVR-MCU-DSP-ARM-/290915538588?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item43bbead69c

wires from mic go to center of four of the relays (tx rx audio screen)
then NO and NC goes to the 2 different radios,
so no voltage on relay coils = radio a
voltage on coils = radio b

and 4 spare relays means i can add up to 2 more radios later on.

will this work ?

[David_AVD]

You'll also need to arrange for the shorting of rx to screen on the radio that's not selected.