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

paul swed paulswedb at gmail.com
Fri May 20 12:25:20 UTC 2011


It may need a resistor to ground something that draws 5-10ma. Some GPS rcvrs
need the dc load to believe a antenna is attached.

On Fri, May 20, 2011 at 7:21 AM, Robert Watzlavick <rocket at watzlavick.com>wrote:

>
>
> 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
>
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