Is my Internet connection worsened by having multiple separate powerline adapters?
I have 2 separate powerline adapters. The Internet connection appears to have deteriorated once I set up the second adapter. Does having a number of adapters have an impact on the connection?
Solution 1:
Most likely yes.
Powerline is very similar to Wifi (it essentially sends Wifi via the power-circuitry in stead of via a radio-link).
Like Wifi it uses channels. Each set of Powerline adapters selects a channel to work on.
And, same as with Wifi, if 2 sets select the same channel or (partially) overlapping channels you will get interference which degrades both throughput and latency.
In some PowerLine setups you can manually assign the channels via the web-interface of the adapters. If that is not possible best you can do is unplug one of the adapters and plug it back in, in the hope it will re-establish it connection to the other side on a different channel.
Another thing:
If both sets are from the same brand it is possible that all 4 adapters go onto the same channel in a 4-device setup. (The 2nd set extends the 1 set. It doesn't act as a separate set.)
In that case performance is also impacted as that means that all 4 devices share the same channel and have to wait until it is their turn to send. (There can only be 1 active sender at any time on each channel.)
You can easily verify if this is the case by unplugging 1 Powerline adapter and see if the other 3 keep working. If that is the case you have this 4-device setup.
If this happens to you the only way around it will be by re-configuring the adapters in their web-interfaces (if they have those).
Last but not least:
You may have a 3-device setup with a PowerLine end-point in your router and 2 separate adapters.
In that case the 2nd adapter will always have to be on the same channel so it will degrade performance for equipment connected to EACH PowerLine adapter.
To conclude:
PowerLine works best in pairs. Each additional adapter added to a pair will degrade performance to some extend.