8 way splitter for GPS to kiwi's and GPSDO needed


ON5KQ
 

Hi,
Can anyone recommend a 8way splitter to connect my kiwis and a GPSDO for my lab.
What technology I need to look for, to pass DC to the outside antenna but don't (DC-)connect all Kiwis together... I think the kiwis need to be (DC-)isolated to each other

I do not want to import from outside EU however, as current customs costs are horrendous...

Ulli, ON5KQ


Glenn Elmore
 

Ulli,

I think you are correct in stating your requirements.  I don't have a complete solution to recommend but I did build a DC isolating GPS board that serves to provide GPS to a single Kiwi without also adding a low frequency path.  For those running multiple Kiwi's from a single GPS source, probably an N-way version of that along with a single DC bias tee or connection to one of the GPS ports is what needs to be constructed. But then there's the question of "what is N?" and 2,4 8 way versions of the thing would need to be fab'd.

It's probably simpler to run dedicated GPS antennas on each Kiwi in situations where a good antenna location is close enough. For the general situation like you describe, an isolating filter is really what is desirable.

Glenn

On 6/19/21 4:59 AM, ON5KQ wrote:
Hi,
Can anyone recommend a 8way splitter to connect my kiwis and a GPSDO for my lab.
What technology I need to look for, to pass DC to the outside antenna but don't (DC-)connect all Kiwis together... I think the kiwis need to be (DC-)isolated to each other

I do not want to import from outside EU however, as current customs costs are horrendous...

Ulli, ON5KQ


WA2TP
 

Ulli,

I had this same request and brought it to the attention of Makis SV1AFN.

He advised he is working on an 8 port with filtering (an active splitter with 4 or 8 ports, with filters against cell-phones and towers and for all GNSS bands).

I have tied him in so he is aware of the growing need and interest.

Tom
WA2TP 

On Jun 19, 2021, at 11:48 AM, Glenn Elmore <n6gn@...> wrote:



Ulli,

I think you are correct in stating your requirements.  I don't have a complete solution to recommend but I did build a DC isolating GPS board that serves to provide GPS to a single Kiwi without also adding a low frequency path.  For those running multiple Kiwi's from a single GPS source, probably an N-way version of that along with a single DC bias tee or connection to one of the GPS ports is what needs to be constructed. But then there's the question of "what is N?" and 2,4 8 way versions of the thing would need to be fab'd.

It's probably simpler to run dedicated GPS antennas on each Kiwi in situations where a good antenna location is close enough. For the general situation like you describe, an isolating filter is really what is desirable.

Glenn

On 6/19/21 4:59 AM, ON5KQ wrote:
Hi,
Can anyone recommend a 8way splitter to connect my kiwis and a GPSDO for my lab.
What technology I need to look for, to pass DC to the outside antenna but don't (DC-)connect all Kiwis together... I think the kiwis need to be (DC-)isolated to each other

I do not want to import from outside EU however, as current customs costs are horrendous...

Ulli, ON5KQ


KD2OM
 

Ulli,
I don’t know if an 8 port splitter is available but I am using a 4 port TVRO splitter. The ones meant for satellite TV have one DC thru port and the rest DC blocked. I would imagine the same type is available in Europe. It is 75 ohms with F connectors.

73,
Steve KD2OM 


Glenn Elmore
 

Lots of splitters available but they all end up tieing grounds together which can make a bad situation worse and more complex.
Complete low frequency isolation is desireable but requires special effort.

On Jun 19, 2021 10:31 AM, KD2OM <steve@...> wrote:
Ulli,
I don’t know if an 8 port splitter is available but I am using a 4 port TVRO splitter. The ones meant for satellite TV have one DC thru port and the rest DC blocked. I would imagine the same type is available in Europe. It is 75 ohms with F connectors.

73,
Steve KD2OM 


Rob Robinett
 

Glen is of course right that it is desirable to not have a GPS splitter introduce ground loops between Kiwis.

However like Steve I have been very successful using simple satellite splitters like this one available from amamzon.fr for 16 euros:


At KPH and at AI6VN/KH6 I put the GPS antenna on the roof and ran 30M of RG-6 to the splitter, then directly connected the splitter output to the Kiwis and have run that way for years without problems.  The RF signal gain from having the antenna on the top of the roof more than makes up for the 12 dB signal loss in the RG-6 and the additional 10+ dB in the splitter.

I use no DC blocking.  Test the RFI level with and without the GPS connections to the Kiwis to see if introducing the splitter adds to your RFI.  If so, then a specialized splitter is of course justified.
   

On Sat, Jun 19, 2021 at 9:59 AM Glenn Elmore <n6gn@...> wrote:
Lots of splitters available but they all end up tieing grounds together which can make a bad situation worse and more complex.
Complete low frequency isolation is desireable but requires special effort.

On Jun 19, 2021 10:31 AM, KD2OM <steve@...> wrote:
Ulli,
I don’t know if an 8 port splitter is available but I am using a 4 port TVRO splitter. The ones meant for satellite TV have one DC thru port and the rest DC blocked. I would imagine the same type is available in Europe. It is 75 ohms with F connectors.

73,
Steve KD2OM 



--
Rob Robinett
AI6VN
mobile: +1 650 218 8896


Jim Lill
 

ground paths via GPS can be a real issue. I have found that the Time Machine stuff is very bad.

On 6/19/21 2:46 PM, Rob Robinett wrote:
Glen is of course right that it is desirable to not have a GPS splitter introduce ground loops between Kiwis.

However like Steve I have been very successful using simple satellite splitters like this one available from amamzon.fr for 16 euros:


At KPH and at AI6VN/KH6 I put the GPS antenna on the roof and ran 30M of RG-6 to the splitter, then directly connected the splitter output to the Kiwis and have run that way for years without problems.  The RF signal gain from having the antenna on the top of the roof more than makes up for the 12 dB signal loss in the RG-6 and the additional 10+ dB in the splitter.

I use no DC blocking.  Test the RFI level with and without the GPS connections to the Kiwis to see if introducing the splitter adds to your RFI.  If so, then a specialized splitter is of course justified.
   

On Sat, Jun 19, 2021 at 9:59 AM Glenn Elmore <n6gn@...> wrote:
Lots of splitters available but they all end up tieing grounds together which can make a bad situation worse and more complex.
Complete low frequency isolation is desireable but requires special effort.

On Jun 19, 2021 10:31 AM, KD2OM <steve@...> wrote:
Ulli,
I don’t know if an 8 port splitter is available but I am using a 4 port TVRO splitter. The ones meant for satellite TV have one DC thru port and the rest DC blocked. I would imagine the same type is available in Europe. It is 75 ohms with F connectors.

73,
Steve KD2OM 



--
Rob Robinett
AI6VN
mobile: +1 650 218 8896