[time-nuts] Trimble GPS Antenna's

[Roy Phillips]

A question please . . . . .

In all the considerable exchange of useful information regarding the Trimble GPS units, I cannot recall any mention of the actual specification of the antenna system for these units. My old Odetics used an "Active" antenna which required 12 volts DC to be supplied from the unit and returned the signal in the intermediate frequency range of 40 something MHz. I am aware that the Trimble units also have "Active" antenna systems, which are supplied with +5 volts DC, but what is returned from the antenna  - - is this also an intermediate frequency?

I now have two antenna's awaiting better weather to install them on a single storey building, including a 26dB gain Lucent, which are currently stuck on temporary poles at approximately 15 feet/5 mts. I am surprised at the relatively good performance in this temporary position. In fact I have had the Trimble/NortelGPS unit working with GPS lock, with the Lucent antenna standing in a glass jar in a north facing window (4 feet from ground level !) . Propagation is certainly a very complex matter.
Roy Phillips