Identify Three 4G band and 4G+ sites on ComReg SiteViewer

Thumbnail of ComReg SiteViewer map

The ComReg SiteViewer is a great way of identifying nearby masts, making it a lot easier to tell which side of the house to position a router or antenna.  While the map does not show band #s, the site IDs give very good clues as to whether Three is using band 3 or 20 and has multiple carriers (4G+). 

This can be essential when choosing an outdoor antenna and also before one starts drilling holes.  Band 3 is particularly important on Three as it offers double the bandwidth of band 20.  Most band 3 masts operate on three sectors, compared to just one or two for rural band 20 masts.

Before Three bought out O2 (Telefonica Ireland), the Three network only had 4G spectrum on 1800MHz, LTE band 3.  Once they merged with O2, they made extensive use of the acquired 800MHz spectrum (band 20) in rural areas.  They also operate some masts on the acquired 1800MHz spectrum from O2, but mainly in dense urban areas. 

Three 4G band and 4G+ indication

First let’s look at the 800MHz and 1800MHz each mobile network purchased:

Ownership of 4G spectrum in Ireland

On ComReg’s SiteViewer, sites that operate on Three’s original 4G spectrum (1800MHz only) have a Site ID that start with “THREE_”.  Such sites that list ‘LTE’ in the ‘Services’ operate on band 3 (1800MHz):

ComReg site with Site ID THREE_DO0167and services GSM, UMTS and LTE

Sites that operate on 4G spectrum acquired from the O2 purchase have a site ID that start with “3_”.  Such sites that list ‘LTE’ under ‘Services’ mostly operate on band 20 (800MHz):

ComReg site with Site ID 3_DO0167 and services GSM, UMTS and LTE

If there are two Three sites with the same Site ID number and both list ‘LTE’ under ‘Services’, that is a 4G+ mast.  In the two above screenshots, we can see that both sites end in ‘0167’, so this is a 4G+ site as there are clearly two LTE carriers. These 4G+ sites usually have 3 sectors on both carriers.

On masts that have a “3_” site ID with LTE, but where there the matching “Three_” site does not list ‘LTE’, this Three mast generally operates on 800MHz only.  This is also true for “3_” side IDs that have no “Three_” site ID, such as the following example:

ComReg site with Site ID 3_DO0041 and Service LTE

Three 3G band indication

Both Three and the former O2 network have 900MHz spectrum with extensive use of this band in rural areas.  Like the 1800MHz 4G band, the 2100MHz 3G band offers greater capacity than the 900MHz 3G band.  This makes it a great alternative to 4G in areas that have high contention. 

As 2100MHz frequencies do not penetrate walls that easily, most people that use 3G end up on the 900MHz 3G band that tends to also be congested.  With a good outdoor antenna, the router will generally use the 2100MHz band (if available) in 3G only mode.  I know a few who manage to get 10-20Mbps peak time on 3G where they could barely get over 1Mbps on 4G. A good example near me is Barnesmore in Co. Donegal.

The majority of “Three_” side IDs that list “UMTS” operate 3G on 2100MHz (Band 1), such as the following example:

ComReg site with Site ID THREE_DO0165 and services GSM, and UMTS

Where a “Three_” side ID lists “GSM” only, the corresponding “3_” site usually operates 3G on 900MHz (Band 8) only:

ComReg site with Site ID 3_DO0194 and service GSM.

Identifying the band by EARFCN

In dense urban areas, Three may operate some sites on the former O2 1800MHz band.  Such sites offer greater carrier aggregation capacity.  However, there does not appear to be a way of identifying such sites on the ComReg SiteViewer.

If you are within range of such a mast and have a 4G+ capable Android phone on the Three network, you can use an App like CellMapper or Network Cell Info to check the current and neighbour cell list EARFCN numbers.  In CellMapper, the EARFCN is shown on the row “(EA/UA/A)RFCN”. 

These are the EARFCNs Three uses:

  • 1700 – Band 3 (20MHz bandwidth, 1855MHz)
  • 1275 – Band 3 (15MHz bandwidth, 1812.5MHz)
  • 6300 – Band 20 (10MHz bandwidth, 806MHz)

In the above example, my phone shows 4G+ and lists a mixture of 1700 and 6300 for the EARFCN in the cells list. This means it is using both bands 3 and 20 for carrier aggregation.  However, if it lists a mixture of 1700 and 1275 for the EARFCN, it is using two band 3 cells for carrier aggregation.  Where it lists multiple cells for a single EARFCN, it is using the first cell listed for that EARFCN.

New forum for discussions

As many of my articles are heavily cluttered with comments asking for advice and help, I have set up a discussion forum to discuss about routers, antennas and mobile broadband. I will also post short articles from time to time on the forum, such as how to check the 4G band a Huawei router is using.

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