Powerline Adapter speed erratic

[#1]

Having spoken to Plusnet recently about a blackspot in my flat, it was suggested I try a Powerline adapter to boost the wifi signal in the bedroom.

Having purchased a TP Link kit i wa amazed and was getting pretty decent speeds from it.

However it seems to randomly drop to almost non existent. From up to 40mbps down to 0.11 at times.

Anyone have any ideas on how I can stabilise it? I originally used the adapter to copy my SSID and thought my devices might still be connecting to the router instead of the adapter in the room (if that’s possible?) so tried it with a separate SSID and WiFi name, but still seem to be having the erratic speed.

Any thoughts at all?

[#2]

Powerline isn't really fixable, since it transmits over your power cables.

If you could get a ethernet wired connection, no power lines you would have an absolutely stable connection.

Using Wifi over short distances won't cause too much variability...

[#3]

@DirtyBertie 

The most likely cause is some other appliance that is inducing noise on to your mains wiring. This could be within your property or coming from a neighbour.

Have you noticed whether the speed drop is coincident wuth a domestic appliance being used?

[#4]

Do you have anything connected to mains that has a filter in it, chokes and capacitors in filters can be OK at 50Hz but capacitors in filters can appear as a short circuit at high frequency and severely degrade the signal between the homeplugs.   Some extension leads have filters in them, and a coiled up extension lead is like an air cored choke and at higher frequencies blocks the signal.