[Elecraft] Microham Station Master Inhibit -> K3 ?

[Marco HB9CAT]

Thanks a lot for your reply Joe, my Station Masters are pretty new
(2014/2015) so I shall be safe to connect Inhibit directly.

> Just like Yaesu, SM Inhibit provides +12V to inhibit and pulls the Inhibit
line low to enable transmit (/Inhibit).
Then why do I measure 12V in "rest state", when no switching occurs ? Isn't
it the other way around ? (I can't test it right now)

> PA PTT is inhibited during antenna tuning.  Low power is still possible as
is the case with SteppIR's own tuning relay.
PA PTT is currently given by an MK2R+ so SM PTT doesn't apply; but if SM
would set INH during tuning the K3 wouldn’t TX

Are we both the only ones using Station Masters with Elecraft ? Curious to
gather experiences

Marco HB9CAT

-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Joe
Subich, W4TV
Sent: giovedì, 20. agosto 2015 22:14
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Microham Station Master Inhibit -> K3 ?


 > 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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