Hello
My ISP is Zain SA, does this module fully supports this ISP carrier aggregation combinations? I don’t want to spend another $300 and end up with a module like the RM521F-GL which couldn’t do any 5G Carrier Aggregation with my ISP.
Hi, I am using this on mobily KSA, the network is NSA so. The bands it connects to are: band 1,band 3, band 20, band 77. With this NSA the speed is slow during peak hours. So I have disabled 5g and only use lte, with lte I get at same time 5 bands= band 1, band 3, band 41, band 41, band 41. I have disabled band 20 because it slows down my connection. I hope this helps.
Hi Safwan, Thanks for your sharing your feedback. You’re talking about the RM551E-GL right? Have you tried to use an external directional or omnidirectional antennas, depending on whether you have a line of sight to the cellular tower? I am saying this because 5G is great when it’s optimized. The reason you’re getting slow speeds on NSA 5G is most likely due to the SINR value being too poor. With external directional antennas pointed directly to the cellular tower you will get super high speeds that LTE alone can’t match.
For my case with the SD X65 module and crippled engineering firmware unfortunately LTE is completely garbage in my area. If it wasn’t for the NSA 5G, I would only get 20-30 mbps download and 1-10 mbps upload, but with either band n41 or band n78 I can get 400-700 mbps download and 50-80 mbps upload depending on the time of the day.
Yes I have a router with this exact module. RM551E-GL, it is engineering sample by the way, because there has not been any official release version yet, word is that this sample may stop receiving updates starting from 03 version. The latest firmware is 03. The features in this module are not applicable yet to networks in KSA as far as I know. SD X65 may be still viable option. The problem is usually not with these modules it is the quality of network by the ISP. I learned this because I tried all 3 networks , stc, Zain, mobily, only network which worked well for me was mobily and the reason is good signal quality. The external antenna is different discussion, anything longer then 2 feet and using non lmr cable and you would lose signal quality, e.g if you use simple coax cable and put antenna in roof and bring it down to router then actually the signal loss in the cable will be more then gain. I would suggest you stick with sdx 65 and check stc and mobily in exact same location. Something may be more useful. Also remember if you are using IMEI to use your own router then you have to switch off isp provided router because isp do not allow two devices with same IMEI at same time.
Thank you so much for sharing your insights—especially the note about RM551E-GL engineering samples not receiving future updates. That’s a critical point for anyone considering a purchase.
That said, there are a few points where I disagree. You mentioned that the issue isn’t with these modules. While it’s true that 5G quality in the kingdom leaves a lot to be desired, 5G NSA carrier aggregation is supported, depending on location. The real limitation lies in Quectel’s SD X65 and SD X75 modules, which fail to implement many of the carrier combinations used here. This is a major drawback. For instance, n78+n41 NSA 5G CA isn’t supported by any Quectel module as far as I know, while even a relatively inexpensive Zyxel NR5103E—powered by a 2021 Mediatek modem—handles it without issue.
As for antenna cables, I think the concern is exaggerated. A short length of RG58—whether 2 m or even 5 m— would not be that bad. In my own setup, I use both 2 m and 5 m runs and still achieve strong performance. To keep the RF cabling short, I rely on an M.2-to-USB 3.0 adapter with a long USB 3.0 cable. With Zain, this configuration consistently delivers over 400 Mbps, sometimes higher, and that’s with just a single 5G band. If my modules supported n78+n41 aggregation, I’d likely be seeing close to 1 Gbps. And in case anyone wonders why I’d even need more speed: it’s because I share the connection with my family. With more than 30 devices online at once, the demand can get pretty intense.
RM551E-GL works perfectly fine with all carriers on Saudi Arabia. I’m using it on Zain and it is connected to all supported bands.
regarding the updates, it recently received an update which worked very well specially on optimizing the upload speed, firmware A04.
so i would recommend the upgrade 
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Thank you very much for sharing your experience, Talaquf. May I ask you please how much download/Upload speed you’re currently getting? I know it’s different depending on your towers conditions but because some people were complaining about upload speed in the past I would love to know the current status
Also can you please tell me the name of this openwrt package that’s in your screenshot? Thank you!
currently around 1200 down 130 up on the best scenarios, that’s with latest firmware update A04, previously i was having troubles with the upload, i was getting 30 mpbs max with firmware A03.
package on screenshot is custom package called 3ginfo-lite by 4iceG:
it is not fully compatible with RM551E-GL though 
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