Slow wifi connection after OpenWRT install on TP-LINK CPE710


I've just installed OWRT on a TP-Link CPE710 v1.0 Install etc went fine and I have it set up and configured as a client to an access point to get the internet. I'm about 100 metres from the AP.

I was using the standard tp-link firmware before this, but installed OWRT to be able to get more of the channels as sometimes the AP reboots and comes back on a channel that is below 100 so the standard TP-Link firmware cannot connect.

With the standard firmware I was getting about 100Mbps download speeds and now after the OWRT firmware install I'm seeing less than half that, more often around a third , so somewhere between 30Mbps and 50Mbps.

The connection to the AP doesn't seem anywhere near as strong as the TP-Link firmware, -68/-90 (sig/noise) SNR 40db quality 70% before and now its -76/-105 SNR 28 and quality 48%. The antenna hasn't moved, all I've done is installed OWRT.

I'm hoping there's something simple that I've neglected to set/do and would appreciate any pointers and advice.

thanks in advance

having spent a few days trying different drivers and builds nothing is making a difference, I've had to go back to the tp-link firmware. Shame really as OWRT using all channels was a perfect solution for my issue.

I was getting 2.55Mbps down and 7.68Mbps up with a -79sig and -100 noise on the OWRT firmware, I switched back to the tp-link firmware and I'm getting 52.77 and 38.19 with -69sig and -90 noise. Antenna not moved, nothing but the firmware changed.

Have ordered Ubiquity's similar looking device - only 450Mbps but that's way more than I need anyway.