Soho MK3 Wifi is running at half the speed of LAN1

I am getting half the rated speed when connected to the router via the routers Wifi AP as compared to the LAN1 connection. I am using a WIFI LAN connection to a local access point and have also tested the USB Modem connection using my mobile phones bandwith. When wired to the router on Lan1, I get the rated network speed. When I connect to the router via the Peplink Wifi AP, the speed drops 50%. This is consistently occurring on multiple devices. Laptop, Ipad, and mobile phone. The router is installed in my RV. If I connect my devices via wifi to the local access point (not the routers AP) I also get the rated network speed. The issue is definitely with the wireless output of the router.
I have tried different channels and settings and have now reverted back to default settings with the same results.

Any guidance would be much appreciated.


Define “rated speed” and “local access point”

That WiFi is slower than Ethernet is pretty much normal.

5GHz is faster than 2.4GHz, so you could try configuring an SSID to only use 5GHz. Channel width is also a factor - the wider the faster but the more interference with neighbors. Then too, you may have configured a max speed under Bandwidth control. You also need WPA2-AES for best performance. And, is the Surf SOHO configured to use its external antennas?