External directional antenna for 5G-NSA on FWA510

bejb

I have a FWA510 that is currently using its internal aerial. The service connects to an O2 transmitter about 1.2 miles away, with clear line of sight - but through my double glazed window. I'm getting about 20-35Mb/s up and 15-20Mb/s down (much better than the alternative BT ADSL). The Air app says I'm connection with 5G-NSA with RSRP -97dBm, SINR 24dB, RSRQ -9dB.

I think I could probably get a better (faster & more reliable) signal & speed if I connected an external 5G antenna. I also live in Northumberland National Park, so there may be objections if I used a large external antenna - so I'm considering the Bluespot mini 5G. This is only 5G (3135MHz - 4038MHz, 2x2 MIMO) and so does not pick up 4G.

I'm anxious that 4G is needed for 5G-NSA.

However, I get the feeling that the FWA510 only accepts 5G frequencies through the external antennae connectors - not 4G. And also that, even if the switch is switched to External Antennae, the internal antennae are still used to pick up 4G. So it feels as though putting an external 5G-only directional antenna should work and improve my signal to the router.

Does anyone any any thoughts on this, and how best to fit an external antenna onto a FWA510 to improve the 5G-NSA connection?

I did find the post (below) that suggests this is right for the 5101, but there doesn't seem to be an documentation in the 510 manual on fitting an external antenna:-

'The external antenna ports are only for frequencies higher than 3500 MHz, and the internal antennas are used for other frequencies (lower than 3500 MHz e.g. 2600 MHz and below) when external antennas are connected and with the switch on EXT position; when the switch is on INT position, internal antennas are used for all the ranges of frequency.

When the switch is on EXT position without any external antenna connected, the router works only on 4G/3G/UMTS modes (5G signal could still be received but at a very low level by the external antenna circuit; they made tests: 5G signal with the switch on INT RSRP = -65 dBm, 5G signal with the switch on EXT no external antenna connected RSRP = -90 dBm).'

https://community.zyxel.com/en/discussion/11861/external-antenna-on-a-nr5101-router

bejb

OK, so I tested switching the Ext Ant switch, without any external antenna attached. My theory was that the router would lose the 5G connection but fall back to 4G, still using the internal antennae.

However, that's wrong. The router lost its connection entirely. So switching the Ext Ant switch appears to disable the internal antennae and rely entirely on the external.

So I guess an external antenna that works with 5G but not 4G would not be able to provide 5G-NSA.

To a degree this does help explain things bit. I was unsure when the previous post talked about 'external antenna ports are only for frequencies higher than 3500 MHz'. A lot of the providers use frequencies below 3500MHz for 5G (eg 3400MHz), and so this suggests the external antennae would not work with them.

I wish there was more documentation to support the use of the external antennae with the FWA510.