Wifi connection is really bad

I’m using a MT300A as a WISP repeater. It isn’t much far from the main AP, and in Luci I can see that the main AP’s wifi signal strength is about -70dBm (which would be enough for a good connection) but sometimes it suddenly goes to about -80dBm for few seconds and later returns to about -70dBm.

The worst problem is that the wifi connection is almost completely unusable because I can’t load web pages the most of time.

If the MT300A is really near to the AP (in the same room) connection is really good. Even if I connect my phone to the main AP, the connection is good. So, the problem could be the MT300A.

How can I get a good connection in repeater mode?

How far is it from the main router?

It is far 4,5 meters (about 15 feet) away from the main AP and there is only a wall between them.

How about you have a test like this: what is the distance wifi if you use MT300A as a normal router, connecting a cable to the WAN?

If MT300A’s own wifi still has a good performance, repeater should not be that bad.

Are you using an external antenna version without antenna stick?

I have a MT300A-ext, and its antennae are connected.

If I connect an ethernet cable into wan, the router works good.

nice you said you have Ext version. This is important.

Can you try changing channel?

If Tx is good I don’t see there is a reason repeater is that bad. I think you need to try to test the real speed using your phone when testing as ap. If you only test the signal strength that may not give a correct information.

For external antenna version we have experience that people attach and detach antenna when the devices is powered on and this damaged the radio rx.

All wifi channels are free. So, if I change channel, it’s the same.
If MT300A-ext is really near the main AP, i have a really stable connection and the speed test (on my phone or computer) is excellent.
Me too, I have attached and detached antennae when the device was powered on, it was only once. How can I verify if I had made a damage?

It’s strange: the reapeter works really good with some models of routers, but it works really bad with other models of routers.

It seems that my repeater is not damaged. Thanks for your support!