[time-nuts] WTB: GPS Antenna Splitter

Dave M dgminala at mediacombb.net
Wed Oct 8 11:40:04 EDT 2014

Bob, Thanks for that.  My intent was to mount the antennas on yardarms on a 
mast.  Both antennas will be at the same elevation, just separated 
horizontally by a couple feet (not 10ft).
My concern (and I think you answered it) was how far apart could I place the 
antennas without having to do another survey when I switch them around.
As an alternative, I could enter the antenna coordinated manually into each 
GPS when I switch antennas.  That should avoid a new survey each time. 
Then, the distance between the antennas shouldn't matter.

Thanks for the info!!
Dave M

Bob Camp wrote:
> Hi
> Missed the survey question…
> If a ns in free air is about 1 foot (30 cm), then you probably want a
> survey that is better than 6” to keep the error down. You do not want
> to have the antennas on top of each other, so yes, the GPS will need
> a survey / location each time you change antennas. If you go with the
> 10’ spacing, then you will get some pretty big jumps without
> switching the location.
> Bob
> On Oct 6, 2014, at 4:01 PM, Dave M <dgminala at mediacombb.net> wrote:
>> Does anyone in the group have, or can point me to, a low-cost (but
>> not cheap) 2-port splitter for a GPS antenna?  Those on Ebay are
>> rather expensive.
>> I have two GPSDO units, and have both an older timing antenna and a
>> new choke ring antenna (Thanks, Pete L).  I already have one 2-port
>> splitter (working well), but my intent is to connect both antennas
>> through the splitters and a couple coaxial relays so that I can,
>> with the twist of a switch, allow me to run each GPS from a
>> different antenna, or both from the same antenna.  I would like to
>> gather some data as to the differences between the two antennas.  I
>> know I could switch the connections manually, but I like the idea of
>> a switch to sort of automate the connections, and I'd need another
>> splitter anyway.
>> Before I go to the trouble and expense of building upon this idea,
>> are there any comments as to the value of the project?
>> Some questions come to mind:
>> I'm thinking about mounting both antennas on the same mast, at the
>> same elevation, just separated by a couple feet.  Any problems that
>> I should be aware of by putting both antennas so close together?
>> Will that small distance have a noticeable effect when switching a
>> receiver from one antenna to the other?  Will the GPS notice the
>> difference and want to do another survey?
>> Thanks for your comments.
>> Dave M

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