[time-nuts] GPS Antenna

[Charles P. Steinmetz]

Chris wrote:

>1) I read the Thunderbolt user manual and did not find any meaningful
>spec on the antenna except that it is amplified and uses DC power in
>the coax.  What signal level is the Thunderbolt expecting?   oes it
>want a 24dB antenna or more or much less?

The antenna Trimble specifies has 35 dB of gain.  Tbolts work with 26 
dB antennas, but like 35 better.

>2) I want to feed two GPS units with one roof mounted antenna.  I
>figure that splitters are just a transformers and will not pass DC to
>power the antenna.  There must be an easy way around this.

HP and Symmetricom supply 2- and 4-way splitters specifically for GPS 
applications (see, for example, the Symmetricom 58535A at 
http://www.symmetricom.com/media/files/support/productmanual/097-58535-01-iss-1.pdf). 
They typically have low-gain amplifiers and pass DC to the 
antenna.  Readily available on eBay and (at least in the past) from a 
listmember at attractive prices.

Best regards,

Charles