@David-TP 

Thank you for your response.

I went ahead and purchased the Deco BE65 (single unit), set it up as the main unit, and connected my existing Deco X20 DSL as a satellite unit using Ethernet backhaul. However, the satellite unit only delivers speeds of up to 60 Mbps—and that’s when I’m standing close to it. If I move to the bathroom, which is just about 8 meters away, the speed drops dramatically to just a few kbps.

I’ve run the network optimization option available in the deco app and clicked on "Improve Optimization," but unfortunately, this had no effect.

The main unit provides full speed—around 102 Mbps—consistent with my 100/20 Mbps plan. Interestingly, when the Deco X20 DSL was functioning as the main and only unit, it provided excellent speeds even from 30 meters away.

What can I do to improve the speed when I’m a bit farther from the satellite unit?

  @David-TP 

Hi Dave,

Please refer to the screenshots below — all suggested actions have been followed, and everything appears to be in order. However, the issue persists.

I tested both Ethernet cables by connecting my laptop directly to the main Deco unit, and the speed aligns perfectly with the unit's performance. I also tried linking both Deco units using different ports, but that didn’t resolve the issue. At this point, it seems the problem may lie with the Deco X20 DSL when used as a satellite

  @David-TP 

Hi,

Please see my reply as below:

I see there is no "Connected Clients" under the satellite Deco X20-DSL.

Yes there was no one connected through satellite Deco Unit at that time, but usually there are some devices connected to it. You will see them in images below.

Have you checked on the Deco APP whether the devices are connected to the Deco x20-DSL during the speed test? I wonder whether they might connect to the main Deco BE65 far away?

 

Even I thought the exact same thing initially but no, there are devices connected to Deco x20 DSL, below screenshots proove that. 

 

And is it a very long Ethernet cable between the main Deco BE65 and satellite Deco X20-DSL?

Are you able to unplug the satellite X20-DSL and connect the laptop to this cable to see how much of the network speed? 

 

Yes the cable is long but maximum length would be 23meters, not more than that. and I have checked the speed through that cable, it exactly matches to that of main Deco BE65 when connected to it with the Ethernet cable. So it seems that cable is not the problem. I even checked it through the satellite deco's port and the speed was higher than that of the main Deco BE65, to my surprise!

This is the wireless speed when connected to the Main Deco:

This is the wireless speed when connected to the satellite Deco X20 DSL and standing just in front of it:

And this is the speed in question (when I am in the corner hardly 8 meters away from the Deco x20 DSL and connected through it): it took almost 20 seconds for the speedtest app to connect to its server and start the speed testing here at this location

These are the settings if they can help any bit further:

So I guess the issue is with Deco X20 DSL's wireless network coverage, or I might be in a total blind spot. But I am unable to digest the fact that when this Deco X20 DSL was working as the main unit before arrival of new Deco BE65, it was having excellent coverage even at the last bedroom of the house. It was just at the border of the house in a corner, where I was having the issue of coverage for which I thought that having another added to form the mesh network will expand the coverage, cover the blind spot and resolve the issue, and that is why I decided to get the new Deco and use the existing one as a coverage expander, but looks like it is not doing the exact same thing as it was supposed to do, or I wanted it to do.

So,

How should I check, prove, and conclude that the corner I am referring to is the actual real blind spot for my mesh network?

And why is the wireless speed on the satellite Deco (when standing just next to it) so low when compared with the main Deco, whereas the actual wired speed matches that of the main Deco?

And how should I resolve this without needing to buy or pay for another Deco unit?

 Thanks to you in Advance for considering this!