What type of antenna should be used with EM7455 for GPS? This modem came with Onlogic K300 with two identical antennas for LTE (Main & Aux). I reconnected the Aux connector on the board to the GPS terminal and the GPS is working. Is it a recommended solution? Can I use 3 antennas with the board at the same time? Main & Aux for LTE and an additional antenna for GPS?
Yes, you can use Main and Aux antenna for LTE and a separate GNSS antenna. Using different antennas will work the best. You can get the antenna specifications from section B of the EM7455 Technical Specifications document, https://source.sierrawireless.com/resources/airprime/minicard/74xx/airprime_em7455_product_technical_specification
Thank you. Is https://techship.com/products/external-active-gps-antenna-3m-cable/ is a compatible one? Sorry, I don’t know much about checking the compatibility.
I’m not that comfortable with RF, sorry. You can reach out to your SWI support person. The antenna vendor should be able to let you know quite quickly. Thanks.
Depending on the cable loss attached to this antenna, the gain is a little high at 26dBm. For the EM7455 the recommended net gain of an active GNSS Antenna is between 10 to 15dB. You need to make sure that the net gain of an active GNSS antenna including the cable loss is no more than 20dB so you don’t over load the GNSS receiver. When connecting an Active GNSS antenna to the GNSS port on the EM7455 you also need to make sure that the voltage bias is turned on.
@PDH Thank you. I suppose turning “voltage bias” on is by enabling GPS port, right? Found the following commands
AT!RESET (then wait for the module to be ready again)
Anything else needed to turn on voltage bias? And, EM7455 provides the voltage needed for active antenna, correct?
@PDH actually I got it working. I had to send the following command to enable power to the GPS antenna.