I have a GEP-RC CinePro 4k With the F7 stack and R9MM running BF 4.0.5.  I am experiencing an odd issue where the quad is only receiving a signal every other second.  I'm not sure what is going on, has anyone ever seen anything like this? The same transmitter works fine on my other quad that has an R9MM.



The only change I have made on this quad was to get FPORT working properly, I was not receiving telemetry, discover new sensors (OPENTX) did nothing. I have another quad that I built from scratch, and got the R9MM+FPORT working properly on there. One thing I had to do was to use TX port instead of an RX.

I looked at the GEPRC-STABLE-PRO-F7-DUAL-MANUAL-V1_0 pdf, and noticed in the diagram for the cable pinout that it is RX4. So I snipped the wire and soldered it to the T4 pad on the FC. In BF the receiver protocol is set to FPORT on UART4, serialrx_inverted is off and serialrx_halfduplex is on.

set serialrx_inverted = ON

Also make sure telemetry feature is turned on.

Telemetry feature is turned on. I am using the 'uninverted' pad on the R9MM, inverting is not required. I tried it anyway, oddly I was able to discover sensors, but lost inputs. Turned inverted back off, still have sensors, but it still cycles as shown in image in my first post.

I wonder if I need to flash the FW on the R9MM. I got it as a package deal and figured they did that already as they had it setup to use FPORT originally.

F.port is not standard firmware out of the box. you want to flash with F.Port firmware.

I am aware FPORT is non standard. The quad was a ready to fly setup by geprc out of the box with a R9MM. First thing I did was plug it into BF and did a diff, which showed it configured for FPORT. So I assumed it had already been flashed. Though I don't know what version. I have flashed the latest to my R9M and R9MM (used on a different quad, a second receiver), and they work fine.

I started to take the gep apart to flash it with the latest just to be sure. That's when I noticed that the dipole antenna looks like a section of it has been squished, thinking the wire inside might be compromised. I have not had a chance to flash it, going to finish that up now. I also ordered more antennas just in case.

Your assumptions make sense.

Flashing to the latest has solved my issue. Still using the crimped antenna, guess it's ok for now. Still got the backups on order, always good to have spares.

Good.