LTE-Products - no good quality (or I am unlucky)?

Hi, as backup for my main-DSL-connection, I have a LTE-fallback.

My first one was the LtAP mini

https://mikrotik.com/product/ltap_mini

It had never a good signal quality, but the signal quality degraded over the time until it was not useable anymore.

I replaced the LtAP mini with the WAP LTE kit:

https://mikrotik.com/product/wap_lte_kit

This device died after around 3 month. Totally dead, no LED, nothing…. I replaced this witht he newer WAP LTE kit 2024:

https://mikrotik.com/product/wap_lte_kit_2024

This one worked for around a half year and now only a few pages like google.com loaded. Everything else showed a white page, pings worked. I replaced this agin with the new KNOT.

With the KNOT every works again as expected. But it is my 4th LTE device. I hope the KNOT will not die in a half year. And I have to say all deviced are indoor, not outside in the rain or so.

You did buy new? MikroTik offers a warranty for end consumers. 24 months IIRC.

Have you tried using it with external antennas