[Elecraft] Microham Station Master Inhibit -> K3 ?
Joe Subich, W4TV
lists at subich.com
Thu Aug 20 16:13:59 EDT 2015
> According to the Microham manual this output is provided to be
> connected to Yaesu, TenTec and Elecraft transceivers; I was tempted
> to plug it directly into my K3, but I decided to measure the voltage
> on the Station Master's Inhibit out connector: it's 13V.
Measure the current on the SM Inhibit jack. Early units sourced +12V
across a 2K2 pull-down to inhibit in order to work with some early
Yaesu rigs. Later units have changed the output to a 4K7 pull-up
resistor to +12V and an NPN transistor that pulls the +12V to ground
to transmit. If you see more than 3 mA on the Inhibit line, you have
an early unit.
The K3 Inhibit input is a 220 Ohm resistor to a port on the controller.
The later versions of Station Master should be fine with it (3 mA max
current) but if you have an early Station Master, I'd use a voltage
divider or a series resistor and shunt 5.1V zener diode between the
Station Master and K3.
> Question 2: I assume Station Master's Inhibit is active when this
> signal goes to 0V, so K3's TX INH configuration shall be LO=INH.
> Anyone has experience ?
Just like Yaesu, SM Inhibit provides +12V to inhibit and pulls the
Inhibit line low to enable transmit (/Inhibit).
> Question 3: Station Master is controlling a SteppIR antenna: does
> Inhibit activate during the antenna tuning procedures ?
PA PTT is inhibited during antenna tuning. Low power is still possible
as is the case with SteppIR's own tuning relay.
73,
... Joe, W4TV
On 8/20/2015 7:23 AM, Marco HB9CAT wrote:
> Hello,
>
> I'm optimizing the shack setup and taking a more careful look at hot
> switching; Antenna switching is managed through a couple of Microham
> Station Masters, which provide an Inhibit Output as cinch connector.
> So Inhibit will be set during any Antenna transtition to protect the
> switches, the PA etc.
>
> According to the Microham manual this output is provided to be
> connected to Yaesu, TenTec and Elecraft transceivers; I was tempted
> to plug it directly into my K3, but I decided to measure the voltage
> on the Station Master's Inhibit out connector: it's 13V.
>
> Question 1: Is that voltage OK to be connected to the Inhibit pin in
> the K3's ACC connector ? I prefer to ask before doing it.
>
> Question 2: I assume Station Master's Inhibit is active when this
> signal goes to 0V, so K3's TX INH configuration shall be LO=INH.
> Anyone has experience ?
>
> Question 3: Station Master is controlling a SteppIR antenna: does
> Inhibit activate during the antenna tuning procedures ?
>
> Thanks
>
> Marco, HB9CAT
>
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