[Elecraft] KX3 ACC2 GPIO

[Chris Cox]

I’ve thought the problem through further and have decided to use a simple mosfet switch in the connector shell to invert the TXInh logic sense and configure the KX3 for -TXInh instead of +TXInh.

Hard switching the GPIO pin showed that to be a usable workaround.

73!  Chris Cox, N0UK
chrisc at chris.org or chrisc at BritishCarAndDriver.com


> On Aug 31, 2020, at 12:51, Chris Cox, N0UK <chrisc at chris.org> wrote:
> 
> I wish to interface my KX3 to my portable 10GHz transporter system.  I have the transporter’s PTT sequencer configured to output a +ve TX Inhibit signal which I have been using to prevent my current I/F rig from transmitting until all relays have changed over to transmit.  The current rig is a Yaesu FT-817. 
> 
> I want to be able to simply switchover the PTT/TXInh cable between the two rigs, so that I can continue using the ‘817 as a backup in the event of some problem with the KX3, and so was intending to us the KX3’s ACC2 GPIO TX Inh +ve input just as I do the 817.
> 
> However, it seems that the KX3 actually has some bias applied that requires to be pulled low to enable the transmitter, rather than looking for removal of the +ve signal.  This will mean that I need more than to simple switch over the physical connectors on the umbilical cable.  Although not insurmountable, it’s not exactly ideal.
> 
> Anyone else done this or similar and, if so, what was your solution?
> 
> 73 Chris
> 
> 
> Chris Cox, N0UK
> chrisc at chris.org
>