I noticed something unusual appear in my MikroTik network cell monitor on Three, seeing a second 4G band 3 carrier operating on EARFCN 1275 which I have not seen here in a few years as the carrier was refarmed for 5G on band n3. The only places Three continued operating the second 4G band 3 carrier was in urban areas where they operate 5G on the high capacity band n78.
In the following example, I cell locked my Chateau LTE12 on band 20 PCI 127 which previously would have aggregated a very weak 4G band 1 carrier on EARCN 100. Now it aggregates a very weak 4G band 3 carrier instead on EARFCN 1275:
As the Chateau LTE12 only supports 3 Carrier Aggregation, I tried disabling band 3 temporarily and to my surprise it did not aggregate even the very weak band 1 carrier like it used to with that cell lock.
While I am out of the sync range for my other MikroTik Chateau 5G router to connect on any 5G cell, it has no problem listing 5G cells including on other networks when set to 5G only mode. Initially it displayed a few distant Eir band n3 cells and then displayed n1 cells on an ARFCN 423130 which I haven't seen before:
Using a 5G NR ARFCN calculator gives 2115.65MHz which is a frequency in Three's 20MHz of band 1 spectrum.
Changing 5G to band n1 provides 20MHz of bandwidth for those with a 5G router within range, 5MHz more than the former band n3 carrier they were using. Three is also unlikely to switch off the 5G band for energy saving particularly with it being the only 5G band carrier available in rural areas.
Unfortunately for those with a 4G only router or outside the 5G range limit, this means less 5MHz less bandwidth available from the second 4G carrier. Worse still, there are many 4G routers incapable of aggregating two band 3 carriers with non contiguous spectrum that were able to aggregate 4G bands 1 and 3. For example, the Huawei B535 router Three has been providing on 4G broadband contracts does not support band 3+3 CA, but was able to aggregate 4G bands 1+3.
In the following example, I cell locked my Chateau LTE12 on band 20 PCI 127 which previously would have aggregated a very weak 4G band 1 carrier on EARCN 100. Now it aggregates a very weak 4G band 3 carrier instead on EARFCN 1275:
As the Chateau LTE12 only supports 3 Carrier Aggregation, I tried disabling band 3 temporarily and to my surprise it did not aggregate even the very weak band 1 carrier like it used to with that cell lock.
While I am out of the sync range for my other MikroTik Chateau 5G router to connect on any 5G cell, it has no problem listing 5G cells including on other networks when set to 5G only mode. Initially it displayed a few distant Eir band n3 cells and then displayed n1 cells on an ARFCN 423130 which I haven't seen before:
Using a 5G NR ARFCN calculator gives 2115.65MHz which is a frequency in Three's 20MHz of band 1 spectrum.
Changing 5G to band n1 provides 20MHz of bandwidth for those with a 5G router within range, 5MHz more than the former band n3 carrier they were using. Three is also unlikely to switch off the 5G band for energy saving particularly with it being the only 5G band carrier available in rural areas.
Unfortunately for those with a 4G only router or outside the 5G range limit, this means less 5MHz less bandwidth available from the second 4G carrier. Worse still, there are many 4G routers incapable of aggregating two band 3 carriers with non contiguous spectrum that were able to aggregate 4G bands 1 and 3. For example, the Huawei B535 router Three has been providing on 4G broadband contracts does not support band 3+3 CA, but was able to aggregate 4G bands 1+3.
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