MC7455 Carrier Aggregation

[Catfish]

Using the MC7455 inside of a Cradlepoint CBA850LP6. Connected to AT&T wireless. The Cradlepoint is able to connect to bands 12 & 2 with the standard paddle antennas. I get the strongest signal from band 12 and also the fastest speed. Band 2 is really slow and the signal is not as strong as Band 12. The problem I’m having is the modem wants to use band 2 as the primary band with band 12 as the secondary or aggregation band. In this mode I only get 6-8 mbps down and less than 1 up. If I reboot the modem it will temporarily use band 12 as the primary band and 2 as the aggregation. With this configuration I get 20-30 mbps down and 5-10 up. Unfortunately after a about 5 minutes the modem reverts back to band 2 primary and 12 aggregate with the slower speeds again. If I lock the modem to just band 12 I get 8-10 down and 2-3 up with no carrier aggregation.

Question is how do I get the modem to always connect to band 12 and still use band 2 as the aggregation band? I have identified the two bands by using the AT! Commands and set them to run together. I have also set the modem WAN interface set to AT!Band=0F

[gscheb]

Hello,

First disclaimer that I am still new to allot of this.

Recently went thru this my self. Have T-Mobile where I wanted band 2 as my primary and band 12 as my secondary. Had same issues as you did. When it was the other way around with 12 as primary and 2 as secondary speed went way down.
How I got mine to to stay with the CA that I wanted was using outside antenna. Can only describe as a sweet spot that was found. Can literally go outside and move my antennas up or down two feet and the carrier aggregation will go back to where I don't want it. Honestly stumbled on to this by mistake. By just simple moving the antennas relentlessly over and over trying to find the best speeds. At the end of the day, think we have to remember this stuff wasn't designed for home internet use. Was made to keep a phone connected driving down the road. And for what ever reason at that height mine does what I want it to do.
The antennas used in this set up are two log periodic antennas. They sell some on this site (698-2700MHz Yagi Radome 9dBi-11dBi 4G LTE Directional Antenna)
If you don't want to install an outside antenna yet maybe try some other inside external antenna. Antennas have really helped my set up allot.
Hope maybe this can be helpful to you.

If anyone wants to help explain this sweet spot effect of the CA would like to hear it myself.

[Catfish]

Thank you! I will try moving the modem/router to different locations in the house. If that doesn’t work I’ll purchase an external antenna and try that.

If anyone else has a different idea or suggestion please let me know!

[swwifty]

What gscheb said is exactly what I'd recommend. If you put outdoor antennas up, you'll get band 2 much stronger, and then likely get the speeds you want to achieve. It's also likely that band 2 is much less congested than band 12, so once you have outdoor external antennas you'll see much better performance on band 2.

LTE is very complicated, and yes it was designed as a mobile network first and for most, although it is being used in a lot of places as a technology for fixed wireless applications (home internet like from a wireless ISP).

I can't always explain why the modem will pick one band over another as a primary, I originally thought it was soley on signal strength, but there is a lot of other factors that are impacting the choices it makes. A lot of that logic is hidden from end users as they tend to not ever care, unless us

[Catfish]

What gscheb said is exactly what I'd recommend. If you put outdoor antennas up, you'll get band 2 much stronger, and then likely get the speeds you want to achieve. It's also likely that band 2 is much less congested than band 12, so once you have outdoor external antennas you'll see much better performance on band 2.

LTE is very complicated, and yes it was designed as a mobile network first and for most, although it is being used in a lot of places as a technology for fixed wireless applications (home internet like from a wireless ISP).

I can't always explain why the modem will pick one band over another as a primary, I originally thought it was soley on signal strength, but there is a lot of other factors that are impacting the choices it makes. A lot of that logic is hidden from end users as they tend to not ever care, unless us

Can you recommend an external antenna?

[swwifty]

Can you recommend an external antenna?

It really depends on your circumstances for space and location you have, but i'm currently running these and they work pretty well:

https://thewirelesshaven.com/shop/anten ... l-antenna/

You'll need two of them naturally. Alternatively there is some companies that make MIMO antennas for LTE which are essentially two antennas in one physical enclosure if you are space limited.

[swwifty]

Also here is a antenna review I did a while ago, but is still very relevant. viewtopic.php?f=24&t=251

[BillA]

Hello,

If anyone wants to help explain this sweet spot effect of the CA would like to hear it myself.

The term "Sweet spot" means finding an ideal location for your router where the main and diversity antennas get the proper polarization in relation to the each other, so that when the waves arrive at a slight time delay to each antenna, it allows the radio to take advantage of the MIMO effect (Multiple In Multiple Out). When all's aligned properly, you will notice a considerable speed increase. Moving the router even a few centimeters around can have a drastic effect on the speeds, so try to move it just a little then do a speed test after each adjustment. Sometimes tilting the two mobile antennas slightly at an angle (as much as 45 degrees) can also help. That's in a nutshell, but if you want to learn more about it just search for "MIMO" on YouTube.