I need some help with determining the best placement of my on-board electronics for my plane. For some context, I am planning on using my FMS SkyTrainer 182 as the airframe.

The following equipment are going to be integrated into the aircraft (already purchased):
- Pixhawk 4 (Holybro) as Flight controller
- Pixhawk 4 Power Management Board
- GPS: ublox Neo-M8N GPS/GLONASS receiver
- Sensirion SDP33 Airspeed Sensor Kit
- 3DR Telemetry Kit V2 (500mw, 433mhz)
- FrSky TFR8SB receiver

Video (not yet purchased):
- Not sure but Runcam Micro Swift 3 looks really good
- MinimOSD to blend the telemetry with the camera feed
- Compatible vTx/Rx

Where and how should they (example: all the transmitters/receivers/antennas) be placed? Why?

I just want to avoid a setup that results in a lot of noise/interference. Please feel free to share your thoughts and any resources you can link me to.

- Pixhawk 4 (Holybro) as Flight controller

at center of gravity, both medial and laterally

- Pixhawk 4 Power Management Board

Wherever strikes your fancy

- GPS: ublox Neo-M8N GPS/GLONASS receiver

wherever you want, just keep it a centimeter or two away from anything that might interfere with GPS signal. Mine usually neighbors the receiver

- Sensirion SDP33 Airspeed Sensor Kit

People usually x-acto these into their foam wings.

- 3DR Telemetry Kit V2 (500mw, 433mhz)

away from anything that has to listen for a signal like the receiver or the GPS (probably the nose)

- FrSky TFR8SB receiver

Away from all the noisy stuff like the camera, any BECs, the video transmitter, and not too close to servos. I find that 30 centimeters from the video transmitter is about the "diminishing returns" point as measured in DbM through a spektrum analyzer and if you absolutely must 10 to 20cm isn't all that bad but sub 10cm and it's huge drop in performance.

Where and how should they (example: all the transmitters/receivers/antennas) be placed? Why?

I like to pile all the noisy stuff in the nose and all the listening stuff in the tail because the noisy stuff doesn't seem to effect each other much and the listening stuff drops RSSI or if you are measuring with a spektrum analyzer DbM. I tried using shielded wire such as an old USB cable or CAT6 but just boring old servo wire that is twisted works just as well.

Another option is to have the rx antenna on one wing and the tx antenna on the other wing which works because those are the two objects that are the most sensitive but I don't like this method personally because it causes asymmetry both in unequal weight and unequal aerodynamic drag. If your components are on the fuselage then everything is midline.

Thanks, parajared!