[time-nuts] GPS antenna splitter

[Dan Rae]

On 6/29/2013 11:35 AM, Graham wrote:
> I find my self in need of either splitting a current GPS antenna feed 
> or putting up yet another antenna, I would prefer splitting the 
> current feed.
>
> There are a few options one of which is a Mini Circuits ZAPD-2DC+ 
> splitter/combiner whose data sheet specifically states DC pass through 
> from one port to the combined port. Fair enough, this should work very 
> well.
>
> However, there is another model, the ZAPD-2-N (having type N 
> connectors) whose data sheet states neither DC feed through or not, in 
> other words, it is does not say explicitly that it does or doesn't.
>
> I think the ZAPD-2-N splitter would work to split the antenna but I am 
> sure about being able to feed the antenna through this 
> splitter/combiner and was hoping someone could state yay or nay on 
> that point.
>
Graham, back in the past before I got the 8 way -hp- splitter I now use, 
I used an MCL ZAPD-2 (SMA connectors) for feeding two GPS receivers, and 
it worked very well.  I left one port intact to feed DC to the antenna 
from that receiver, and put a small cap in series with the other to 
block that one.  As the second gps connected to that port then 
complained I added a 220 Ohm R in series with a small choke to ground 
which lets that receiver think it is powering an antenna.

Unmodified, there is a DC connection between all three ports which I 
think would not be a good idea for two receivers both looking for a 
powered antenna.

If you can find one of these splitters cheaply, it's a very good way to 
go, but I wouldn't want to pay the new price for one :^)

Dan