Carrier aggregation not getting all bands RM520N-GL

Hi @meloserj, hope you are well! I have GL.inet X3000 with Rm520-GL and it does only 3x CA and I am considering to buy RM520-EU or RM521F as it can support 5X CA. what modem are you using? did you see any improvement with upload speed after RM520-EU. did you configure everything from scratch or just plug & play. please share your experience.

Kind regards, Mahe

Hi @Mahe
Actually I replaced my 520-GL with 520-EU as I am living in MEA and the GL was not doing the CA I wanted. The European version is fully compatible with my network, however the CA has one frequency less than what I used to have on Netgear M5.
But so far its stable and I received the latest firmware. Its on development board from aliexpress and connected 24/7 to network. Just 2 times I faced 5G-NSA dead cell, which I rebooted the modem.
Hope this helps
Cheers

I have the same bands plus B38 and N3. I have yet to buy the module and I’m wondering if this is a risk I could face. I prefer GL because has much more bands, but I’m trying to understand if such issues only involve specific service providers in some countries or everywhere. I don’t see many people in Europe using EU modules and I was going to buy GL like all the others until I had the luck to find this thread.
Also, is this module upgraded to the latest version capable to aggregate B38 and N3 bands in addition to the ones you posted above?

What this means in concrete terms? Reduced speed? Did you get the same performance of Netgear M5. Between all the plenty of reviews I had chance to see, the M5 was the faster one and would be amazing if we can get similar performance with RM520N.

Quectel is the worst when it comes to implementing CA combo. It can only do 2-3 bands combo while other modems in commercial routers can make 5-6 combos and the ironic thing is they charge much more money than complete routers with wifi and all. Many people bought RM521F-GL and they never released even a single firmware update to it and after they sold their inventory they said it is abandoned product even though it was being advertised on their official website and YouTube channel.They have no respect to their customers. Thats why I will never buy a modem made by Quectel again.

Semsem, what you are saying are the same reports I see all over the web and the reasons which forces me to be very careful.

Unfortunately I have to confirm such statement:


And yes, such routers are even cheaper. I honestly asked myself multiple times if I should buy one of such routers and just enable only the modem part.

And this is why in the thread I opened here, the firmware status is one of the things I asked. This behaviour is well known.

They keep CA combinations for RM520N-EU secret and hidden due to what they call “strategy”.
So, I’m wondering how a customer can choose between models when details needed for comparisons are not even exposed.
So, as of now, basically, the only solution I found is what people has done here: buy -GL and see if works. If not, send it to the trash and buy -EU.

This is what already does an old FM350-GL which costs 3 times less (and in any supported band, not just 1 3 7 20 N78).

I plan to place the modem outdoor and Quectel is the only one that works well in pcie mode allowing in this way an ethernet PoE connection. However, I feel like I could achieve the same results with a cheap module like that and save at least $150. Only difference is that the connection has to be made via USB and 3.0 maximum length without signal degradation is 3 meters while I probably need 5 meters and more. The good news is that exists active extension cables and they are cheap.

There’s another thing I have to understand. RM520 max bandwidth is 120Mhz, 200Mhz for the other module. Such combos exceeds 120Mhz, and this to me seems exactly what experienced the guy (although I have not yet understood what he means for “one frequency less”):

Does this translates in reduced speed? I have no idea.

What I’m trying to understand is if an expensive Quectel module can provide better performance, but from what I have read here and elsewhere, not only there are concrete risks that it will perform just like an old cheap module, it could perform even worse (if my assumption on bandwidth is correct).

These modules are advertised as “LTE 5CA + NR 1CA” or “LTE 3CA + NR 2CA” and I’m trying to understand if, RM520N upgraded to the latest firmware, can do this. And if it can, how 120Mhz bandwidth limitation can affect performance.

Semsem, what are you using now?

I am currently using RM521F-GL but due to the undercooked unupgradable firmware it has it only does 3 LTE plus 1 NR which is bad for SD X65 modem. My tower supports LTE plus n41+n78 but the module firmware doesn’t which reduces the speed significantly. You’re right about the PCiE to ethernet advantage of the Qualcomm modules(not limited to Quectel) and this is the only reason I am still using it instead of a router made by H or Z. The signal is not good inside the house and the PoE board is very useful in this situation. What pisses me off is it should be very easy thing for them to add these CA combos to the firmware but I guess they have no strategy or incentive to support certain regions of the world.

Oh my God! This is Snapdragon SDX65 and you even get one band less than an old Mediatek T700 (FM350). I understand your frustration!

Same for me, except N3 instead of N41. The above user reported the EU version able to aggregate 1 3 7 20 N78, but I would prefer B38 rather than B20 because provides more bandwidth and there’s no way to know if such combo is supported because CA combinations are kept hidden. And for the same reason I don’t know if can do N3 + N78 + XX LTE.

Well, I’m not sure it’s an advantage. USB3 adapters are much cheaper and through the same USB cable you provide power and data transmission. So, just one cable like PoE ethernet. With $5-10 dollars more you can extend the cable length from 3 to 5-6 meters (and more) without signal degradation through active USB extenders and this is enough for most people.

Apart from this, had you ever chance to compare speed between pcie mode and usb mode? I have read that USB mode requires more processing power to get fast speed and my CPU has plenty of power. I can only find good reasons for expensive pcie mode modules if, compared to USB mode handled by high power CPU, pcie mode is still faster.
I saw FM350-GL going at 1.2Gbit download speed (and more) in USB mode and is very hard for me to believe that pcie mode can do better. Do you have more info on how these connection modes compare? Because honestly, if I end up with the same speed in boths the modes, then all the extra money needed to build a pcie connection would be a waste of money.

Yes, I agree and in the specific case of RM521F-GL, given that it’s an abandoned product, why not open sourcing the firmware like does many companies when they don’t care anymore about a product?

I actually have a 20 meter USB 3.0 cable I originally bought before the PCIe to ethernet kit became available. My intention was similar to what you’re suggesting. It didn’t however work good for me but it wasn’t entirely the fault of the USB cable. Because I didn’t fixate my M.2 to usb kit properly the heavy weight of the USB 3.0 cable dragged the whole thing with it and the cable ended often disconnected from the kit. Additionally also my openwrt running Netgear r7800 router to which the USB 3.0 was connected was not stable enough because the modem would disappear every other day or so and would required me to go all the way to the top of the house to power cycle it. When it worked the speed was the same of the ethernet wired connection. However I was only getting 200-300 mbps from the tower so I can’t be sure what is the max speed an USB 3.0 connected to my openwrt router could possibly gets. I am limited to the amount of testing I could do because I have a huge number of family members all leeching from my internet subscription and will be dissatisfied if the internet goes down for any appreciable amount of time.

Sem, the sharing of your experiences is much more useful than all the comments of the customer support put together.

I suppose this was an active USB3 cable because a 20m regular cable should not have worked at all. I can’t find active usb cable of such length (max 10 meters). One important thing to note is that I read that the non-active cable and active cable must be of the same length in order to work properly (not sure how can negatively affect functioning when this rule is not followed). In your specific case, 10m of regular cable + 10m active cable. Problem is that regular USB3 cable starts signal degradation after 3 meters and I suppose the active cable can’t rebuild anymore degraded data. It will probably need a different configuration?

Yes, this is normal, if the end points of the cable are not firm. This has more to do with the lack of some fixing strips than else.

I think may have to do with power drop. 20 meters is really a lot, but active cable also handle power. From what I read here it may have to do with the quality of usb active cable or USB ports going into sleep mode (on modem or router side). Did you tried to connect directly to a Windows computer where you can at least exclude one side of the communication by disabling sleep mode?

This completely surprises me especially at a distance of 20m. USB3 can handle 5Gbps, but in reality even a 2.5Gbit ethernet port is much more than enough for 5G NSA. So, there is no bottleneck in the 2 connections (as long as the CPU has the required power to handle USB data transmission). If you was getting the same speed, then this gives me really good hopes, but are you sure it was not USB2.0 (200-300 mbps sounds more 2.0 than 3.0) and are you sure the ethernet cable was of the right cat? If you still get 200-300 mbps with a cat6, then it must be related to how you connect to the tower and signal. Even if you’re RM521F-GL only aggregates 3 LTE, the real high bandwidth comes from NR. I saw with my eyes n78 alone going at more than 500Mbps. I think you should investigate more on the possible issues, if the tower is good and your settings are optimal, you should get nearly 1Gbit with N78 and 3 LTE. The one LTE you miss due to unupgradable firmware should not make big difference. I would also check if there are transfer rate limitation on your subscription plan.

I was near to the decision to buy RM520N-EU, but after I saw your experience I really have doubts that could be a waste (a big waste) of money. Let see in my other thread what customer support will tell me about the supported combinations.

Such a bummer only see the discussion after I bought and set up rm520n-gl

Anyone know why the modem only wants to connect to 5G band with 2ca though if I set it to LTE only it does register and connect with 3ca getting 150 Mbps DL.

Btw with 5G n41 2ca it can reach 500 Mbps DL, it’s good enough however I’d image its even better it could also aggregate one or two LTE bands

This is the most diffused module and most people are not even aware of the european version. They just think this is how is supposed to work.

I’m afraid the only workaround is switching to the EU version (or a cheap $40 FM350-GL if you don’t need pcie mode).

With the 2 missing bands, the right bands, the right configuration etc, I saw more than 1Gbit.

Thanks for the quick response.

I played around a bit and was able to make it aggregate LTE and 5G bands

  • change network mode from auto to NR5G:LTE
  • disable 5G SA so only uses 5G NSA

That way, I can see the modem get 3CA with B2 and 2x n41, or sometimes B2 B66 and n41. DL doesn’t improve however UL is better.

Unless quectecl releases new firmware to fix the CA, I guess that’s pretty much it…

What the speed you achieved after the changes?

Not sure I have understood well. Can you list the whole combo (band by band) ?

DL stayed the same, max around 500Mbps, UL is better at 50-70 Mbps

AT+QCAINFO

+QCAINFO: “PCC”,850,100,“LTE BAND 2”,1,477,-105,-14,-68,0
+QCAINFO: “SCC”,520110,12,“NR5G BAND 41”,450,-103,-11,874
+QCAINFO: “SCC”,502110,3,“NR5G BAND 41”,1,450,0,-,-,-103,-11,874

OK

Hi sorry for the late response

Yes it was an active USB 3.0 purchased from AliExpress and it seems like well made. It has micro usb ports for power supply because like you said the transmission can be degraded because of the length. However I didn’t connect any power to it and it worked fine on my computer there was no issue of disconnections. I suspect the culprit is my openwrt router either the USB ports or the Openwrt system.

The speed I mentioned above was few months ago and were on n41 before n78 became available in my area. These days on n78 plus lte 1 and 20 I get about 500 mbps. I haven’t tried again the USB 3.0 cable because my family don’t like downtime at all haha.

The aggregation of 2 NR bands is something I still have to understand and Semsem may correct me If I’m wrong, but due to LTE rebranding, when in NSA, “N41 + N41 + B1” is like “B41 + B41 + B1”. You miss two bands in the combo.

Do not worry. This is a very good news!

Yes, it could. This was a commercial router or a DIY one where you have more control on hardware? Did you tried “adapter > regular short USB3 cable > router” ? You should experience the same disconnections. If not, then it must be the router not able to provide enough power.

I forgot that part. 200-300mbps? qliten should feel lucky with its 500mbps, but we are still very far from NSA capability.
N78 alone should provide at least 500Mbps (I saw with my eyes). You may want to check why you don’t get full speed after having excluded is not related to the tower side for which you have no control. I would first try with high gain antennas.

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Nope I have a great signal with 4 external antennas connected to the modem but my ISP is not great in my area but 500 mbps is enough for the time being especially since the RM521F-GL has been crippled by Quectel. Never again Quectel. Fool me once shame on you, fool me twice shame on me.

I wonder if MTK 5g modules like the T830 support M.2 to ethernet boards. it would be a great alternative to the Qualcomm SD.

If I were you, I would try to sell your RM521F-GL. You should be able to aggregate the missing bands with something cheaper without extra money.

I have not yet entered into this area, but I certainly want to replace the cheap ones that comes with the adapters. Do you have something to recommend?

I asked myself the same multiple times. Fibocom, with their FM190W-GL, switched to SDX75 and I’ve not been able to find anything in the middle (something newer than the old FM350, but not even so much like FM190).
But exist T830 based modules?

I don’t think anyone would be interested in a module with unupgradable garbage firmware that can’t even support 5G CA in my country. I am not as crooked as Quectel to sell others unfinished terrible product.

Regarding the external antenna I don’t use anything fancy or branded. Just 4 separate directional antennas pointed to the cellular tower.

I found FG370-EAU T830-based 5g module on Alibaba which is an LGA module with an M.2 pins. It’s quite interesting if it can be deployed on M.2 based routers.