External Supply Needed for GPS-21801 antenna?

GPS/GNSS Development Boards
1

I’m looking at ordering this antenna: GNSS Multi-Band L1/L2/L5 Surveying Antenna - TNC (SPK6618H) - GPS-21801 - SparkFun Electronics.

  1. Would this be suitable for use with this GPS/RTK receiver? SparkFun RTK Express - GPS-18442 - SparkFun Electronics

  2. Do I need to supply 5V separately or will the 18442 GPS receiver supply it?

  3. If I need to supply 5V separately, does the antenna come with a 5V supply?

  4. If I need to supply 5V separately and the antenna doesn’t come with a 5V supply, what kind of power jack does the antenna have?

2

Most, if not all active antennas are powered via the antenna connection on a single shared lead. It is easy to isolate the RF signals from the DC power component.

The schematic for the SparkFun RTK Express - GPS-18442 receiver that you asked about clearly shows the power connection and is stated to be compatible with this active antenna: https://www.sparkfun.com/products/17751

I think you can be confident that the antenna will work with the receiver of your choice, but it would be best if Sparkfun employees responded more promptly to a potential sale.

3

Hi KurtA,

The GPS-21801 antenna is an excellent choice for the RTK Express (GPS-18442). The Express outputs 3.3V via the SMA connector to power the antenna. You will need an SMA-TNC cable too: CAB-21739 (300mm) is useful if you are mounting both the antenna and Express on a survey pole; CAB-21740 (10m) is a better choice if the antenna will be outdoors and the Express indoors.

Best wishes,

Paul

4

Thanks for the clarity of the answers!

5

Indicates 3.0 to 5.5V

Should work on the majority of uBlox receiver designs which push a DC bias onto the RF Feed Line via a inductor and 10 R current limiting resistor.

Measure the DC at the far end of the cable, if really long, to check the DC bias is still adequate.

48mA on the higher side, but not excessive. Just eats in to over-all power budget. Can measure via a bench supply instead of plugging into receiver.