Hi,

I have a Vigor2866Lac with a Vodafone 4g SIM. The cell tower is located 150m away in direct line of sight which connects on Band 1 at 2100MHz. There are no other Vodafone cells in this location which is a small rural town. The router is connected directly to the PC with the DrayTek 1m LAN cable, there is no switch or other devices. The router firmware is the latest version.

The maximum downstream performance achievable with this setup 130Mbps. But when I put the same SIM in a Google Pixel 6 phone it achieves 200Mbps.

The speeds quoted above are with both the stock LTE Aerials and a Poynting XPOL2-v3-5g (which is a Directional aerial and covers the 2100Mhz used by Band 1). Mounting the Poynting in an elevated position facing the cell makes no difference, it's the same speed as when the aerial is on the floor of the house facing the ceiling.


The LTE > Status of the router dashboard reports
Signal Strength(RSSI) is -42 dBm and Signal Quality(CINR) is 58dB (99%).

I understand the Pixel has a different modem however the Vigor2866Lac has a Cat 6 LTE that is theoretically capable of 300Mbps downstream, and as far as I can tell is in a near perfect environment to achieve high downstream speeds.

Can anyone advise why the Vigor2866Lac can't achieve a downstream speed closer to the 200Mbps of the Pixel 6?

DrayTek technical support reviewed the router configuration which was stock and recommended enabling Hardware Acceleration - this made no difference.

I saw a Draytek forum post advising to match the MTU setting on both the router and Windows - I checked and mine are both 1500.

I understand from the posts linked below that Carrier Aggregation can combine multiple bands to acheve higher speeds and that the cat6 modem in the Vigor2866Lac is capable of aggregation. According to cellmapper.net the cell tower I'm connected to has Band 1 and Band 20 but Dashboard > LTE > Status indicates the router is connected to Band 1 only.

How do I confirm Carrier Aggregation is enabled on both the cell tower and my router?

https://forum.draytek.co.uk/viewtopic.php?p=99495&hilit=lte#p99495
https://forum.draytek.co.uk/viewtopic.php?p=97774&hilit=lte#p97774

Has anyone seen a DreyTek cat6 LTE achieve more than 130Mbps or is this the maximum real world speed achievable?

Should I look at a different external aerial or even a different router like the Teltonika RUTX14
4G LTE CAT12 (https://teltonika-networks.com/product/rutx14/)?

Can anyone suggest anything that's not been covered above?

Thanks,

Chris

I think 130mbps is pretty good to start with - the best I've seen is around 80 with most 4G+ connections. The antenna you're using looks good, it has both antennas so MIMO will still work.
Cat 12 would most likely be a bit quicker, but you should also check whether your 5G capable Pixel 6 is definitely using 4G in that instance. It should show the 4G logo for regular single carrier 4G, 4G+ for LTE-Advanced which has carrier aggregation, or 5G.
Personally I've only seen 200mbps and above on 5G so far.

You can check the band usage by entering in these two special modem AT commands in the router's Web Console .
From my checking, it seems that these commands are ONLY for the CAT6 modem models:

> wan modem AT+QCAINFO
> wan modem AT+QNWINFO

You can try entering those while idling and when doing a speed test, it should generally only use the extra bands when it needs to so might only show CA on large downloads and things.

I think 130mbps is pretty good to start with - the best I've seen is around 80 with most 4G+ connections.

I agree, it's the fortunate location of the cell tower that allows the Pixel to achieve 200Mbps. I still want to figure what's involved in achieving as close to the same via the DrayTek, or if there is a bottleneck that is insurmountable. At the moment I think it might be the DrayTek's Cat6 Modem but don't listen to me, I'm here as I don't know what I'm talking about.

The antenna you're using looks good, it has both antennas so MIMO will still work.

Again the fortunate location seems to produce the same result from the stock DrayTek aerials (direct to the router, not the 1m extension).

Cat 12 would most likely be a bit quicker, but you should also check whether your 5G capable Pixel 6 is definitely using 4G in that instance. It should show the 4G logo for regular single carrier 4G, 4G+ for LTE-Advanced which has carrier aggregation, or 5G.

5G is not available in my location from any provider including Vodafone (the one I use). I've never seen any logo other than 4G on screen or any of the apps that provide detailed information eg. Network Cell Info Lite.

I am tempted to try to get hold of a Teltonika RUTX14 to test. Or potentially a smaller (cheaper) unit that I can piggy back the DrayTek with and swap it out for a 5G capable alternative once something is available and 5G becomes available on the cell tower I use.

Personally I've only seen 200mbps and above on 5G so far.

Here you go. Interestingly the speedtest.net screenshot shows LTE greyed out just in front of VODAFONE right below the Ping speed. The phone itself shows 4G on the toolbar.

You can check the band usage by entering in these two special modem AT commands, which from my checking are ONLY for the CAT6 modem models:

> wan modem AT+QCAINFO
> wan modem AT+QNWINFO

You can try entering those while idling and when doing a speed test, it should generally only use the extra bands when it needs to so might only show CA on large downloads and things.

I did this from the web console - was that the correct thing to do? The output wasn't what I expected - see below.

```
> wan modem AT+QCAINFO


OK
> wan modem AT+QNWINFO

AT
OK
```

Edit - this was on idle.

Hmm, that does suggest it's just using 4G - In that case it's possible that LTE Category 6 is limiting the max potential throughput.

For those commands, those used to work but it's possible that was just with a specific test firmware or older LTE modem driver, that's a shame it doesn't output anything useful now. I'm not sure how else to check the carrier aggregation status.For 130mb real throughput, that would have to be using carrier aggregation.

I think I'm starting to understand, almost.

It looks like LTE Cat6 can aggregate up to 3x20Mhz component carriers. So the 130Mbps downstream I achieve is likely to be 1x20Mhz carrier + 1x10Mhz carrier?

The calculator at cellmapper.net shows at 64QAM this would be 150 + 75 Mbps = 225Mbps theoretical - which may work out to 130Mbps real world? This would be almost 60% efficient - but is starting to involve a lot of unfounded guesswork.
https://www.cellmapper.net/4G-speed

Plus I don't know how to identify the Downlink Modulation xQAM to narrow this down. I can't see this indicated anywhere on the DrayTek Dashboard.

So I could call it good at 130Mbps and be content it's above average. But I'm struggling to ignore that nearer 200Mbps is achievable with the right equipment, especially when I need to shift fairly large files around the internet several times a day.

I still think it's the Cat6 Modem, really because I can't see there being that much loss in the Poynting aerial. So unless anyone can advise on a configuration setting that's been missed it looks like the only option is another router (piggy backed off of WAN2) or an external LTE modem?