@delong91 Thank you for your reply.

First of all, no adapters came with my Deco box! Please see the photo showing the included items! (I only got an ethernet cable).

Secondly I will try to get the same antenna as you did, since you tried it and it works.

But now, I am mainly concerned that maybe the adapters I got are not correct, and this is why the antennas I have don't work.

Can you please show me a photo of the contents of your Deco included items? Can you also show me a photo of the adapters that came with your deco? Are they the same as the ones I purchased or are they different?

@David-TP Can you please explain why I did not get adapters with my Deco X50-5G?

  @delong91 

Thanks for your reply.

So ok at least the adapters I got are the same as yours.

Imagine that without external antennas the x50-5g connects automatically to N78 bands. The signal is low but it still connects and I have the best speeds.

So I bought the external antennas to strengthen the signal, and as soon as I connect them and enable them, the X50-5g cannot connect to N78 and reverts to n1 or n28 and the signal SNR fluctuates.

It is like the internal antennas are stronger and can pickup the low n78 signal, whilst the big external ones can't. Or it's like the external ones are not connected...

As soon as I revert to the internal ones, I get N78 and the signal is much more stable.

  @delong91 

I don't want to cell lock because the pci of N78 changes during the day(s). I sometimes get connected to n78 with pci 406 and others with pci 73.

If I cell lock, some times per day I lose 5G signal completely.

So I just want to lock the band to n78.

The internal antenna handles this just fine. 

The external antennas (even if supposedly are stronger) they lose the signal of n78...

  @delong91 

Fyi, I ordered the same antenna (Poynting XPOL 2 V3). As soon as I get it I will run some tests and let you know.

Again, many thanks for your help.

  @madvinegar I experienced the same issue with the Bluespot antenna, which is similar to the Poynting antenna. It seems like a software problem where it can’t consistently select the fastest band.

As a developer myself, I find it frustrating not being able to fix or debug some of these bugs. I really wish TP-Link’s firmware was open source so the community could help address these issues.

  @Bader-bsn Thank you for your reply.

I can understand that the system may choose the band that has stronger signal. But this should be done only when it is in auto mode.

When I select and lock the band I prefer (because it is faster), I want the system to stick to this band, even if the signal of this band is weaker. 

I really hope this relatively easy problem is fixed.

The only way to achieve the band lock is only if I also Cell lock. Which is not ideal because bands change PCI during the day.

Fyi I have not received my poynting antenna yet. I will keep you advised. Hopefully there is some software update till then to correct this issue.

  @madvinegar can you share a link where you bought this antenna? 

  @Bader-bsn 

This is the antenna: https://poynting.tech/antennas/xpol-2-5g/

I got it from a local shop. Make sure you get the "v3". It is the latest and most advanced version of it.