[time-nuts] 58536A splitter and 9390-6000 GPS

[Robert Watzlavick]

On 05/19/2011 10:35 PM, WB6BNQ wrote:
> Robert,
>
> Two questions.
>
> First, what is the voltage at the 9390 antenna connector with nothing attached
> besides your DVM ?
>
It shows 5V open circuit.

> Second, what happens if you just attach the antenna straight to the 9390 ?  By
> this i mean if voltage is on the antenna connector and while you are observing it
> and then attach the antenna what happens ?
>
I found something interesting here - with it connected straight to the 
antenna, I measured 4.6V.  I connected and disconnected it several times 
and didn't see any drops.  But, after the 5th connection or so, I 
finally got the 9390 to show the same behavior as with the splitter and 
shut off its antenna supply.  So it seems it's not exclusive to the 
splitter but just that it occurs more often.  The antenna is connected 
directly to the little GPS daughterboard module and I don't have 
schematics for it.

This isn't a showstopper, just interesting behavior.  One of the things 
I like about the 58536A is that it will continue to power the antenna if 
you remove other receivers from the ports (for troubleshooting etc.)  I 
guess with this particular receiver, it is a little more sensitive to 
antenna disconnects while it is powered on.
> I suspect there is some protection process with the 9390 and the load or reverse
> voltage present from the splitter is causing it to activate.  However, I am not
> familiar with that unit.  Just asking general troubleshooting questions.
>
> Bill....WB6BNQ
>
Agree - thanks.

-Bob