Raspberry Pi and Noise

Raspberry Pis make a lot of noise. I have a stack of 3 x 3Bs. 2 of them are 3B+ RPis
The old 3B drives my dump1090 receiver with green fake rtl-sdr v3. It barely raises the S meter on my nearby FT-817 tune to 2m band.
When I turn on the power to my genuine V3 ID-568 receiver, it raises the noise by 6dbm measured with SDRPlay. 2 dbm from the rtl-sdr. When I turn on my ID-724 an old blu rtl-sdr the noise goes up to S8 on the FT-817 S meter. I have all the RPis in aluminium cases I found on fleebay. The cases are connected to the shack ground. All the power-cords have clamp on torroids. Some of the cheap fleebay rtl-sdrs don’t have their metal case grounded. I fixed that. the antennas are QFH antennas so they are grounded too. I don’t know where else to go. What have I missed? Has anyone else similar noise problems? How did you fix it?
73 Bob vk2byf

I have a similar problem with mine and can only echo that they are noisy. The only thing that made any difference for me was to use wifi over the Ethernet. Everything was fine for 2 out of my 3 but the last one drowned everything out. Back to wifi.