Domoticz

Since few days all z-wave devices on the same side of the house are marked dead and won't connect. This affects not only the battery operated like SpiritZ heating valves, as also wall plug adapters and wired FRGBW controllers. In my country LTE is in extension buildup in favor to 5G and the problematic devices are on the side of the house to the next cellphone tower (500m). So to understand let's have a look for the conflicting frequency.

LTE Band 20

LTE Band 20 is a part of the FDD (Frequency Division Duplex) LTE spectrum that has different uplink and downlink frequencies. The separate uplink and downlink bands allow for simultaneous transmission on two frequencies. The bands have a separation between them which is called the band gap.

Uplink Frequency: 832-862 MHz
Downlink Frequency: 791-821 MHz
Width of Band: 30 MHz
Duplex Spacing: -41 MHz
Band Gap: 71 MHz

Here LTE 20 uplink can operate at 862Mhz + 30Mhz hub and so inside the z-wave signals. While LTE devices can send with 2 watts, our z-wave devices do loose. My final question is: Is z-wave in near future a reliable technology or end now with new cellphone frequencies and are 2.4Ghz devices a better solution?

Solderbro

If that's uplink... means the problem does not come from the base station but your own mobile phones + they may have some filtering issues? Try to switch them off!

Okay it took some time.

I glued aluminium coated insulation behind my heating valves to limit the signal from the outside. Nearby i placed plugs from everspring and hank to have mesh repeaters. The Pi 3b+ seems to spread frequency distortion, even in a metal case like here, so i took a 30cm USB extender cable. The Aeotec stick is now at a distance to the pi and the signal has become more stable.
In the Aeotec setup i increased the wait time from 3000 to 4000 to have more change for node answers.

But the LTE 20 band is a problem, if you have it nearby it can crush the signal.

Solderbro
(Question solved)