Operating f9p base and rover with long distance antennas

Hi, I have a f9p base and rover communicating through two RFD 900+ modems as shown in the attached photo. This setup works for short distances. But I need to use my base and rover 10km apart, in a scenario similar to this https://electronics.drotek.com/?p=6785. These are my questions.
(1) What antennas I need to buy for this new requirement?
(2) Please explain how to connect the new antennas.

Appreciate your help. Thanks.

Hi there, I have never tried the RTK setup with RFD 900+modems.
However, if you can manage to configure the radio kit via 3DR Radio Config software, you will be able to communicate from the base to the rover.

Additionally, it is best to review the RFD radio modem software manual:

Maybe, you are using the telemetry antennas in the wrong way. You can probably change the small antennas and purchase the same antenna for the second connector.

Best Regards,

You could use the small antennas on one telemetry kit and the bigger antennas on the other telemetry.

Thanks Anthony. I replaced the small antennas with bigger ones and it helped. I am using the rovers with ground robots and there is no line of sight (several buildings and many trees). I receive a weak RTCM stream to the rover operating at 1-2km away. I am thinking to upgrade the Base telemetry antenna to a higher gain antenna but still not sure which antenna to buy.