I'm using a external taoglas GPS/Glonass active antenna. It has a male SMA connector and I don't see where any voltage source hooks up to thing. So how is it active? Or does the power required for the internal active components come in on the signal line (center conductor of connector)?
The datasheet says "active" but I don't see anywhere in the datasheet it talks about it.
Best Answer
The antenna has a low noise amplifier inside so that the long cable will not add as much noise. You need to use a bias tee to power the amplifier via the signal wire. Basically, you need to add a DC blocking capacitor in series with the signal line and then hang an inductor off on the antenna connector side side of the cap. Feed the DC in through the inductor. You may want to add some filtering on the feed into the inductor to make sure you don't get RF leaking in or out. You can also buy a bias tee that has these components built in. I would only recommend buying a bias tee for testing purposes, it's much cheaper to build one in to your circuit.