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.

4 thoughts on “Identify Three 4G band and 4G+ sites on ComReg SiteViewer”

  1. Hi Sean,
    Great website.
    I wanted to post my own findings having recently installed an external directional 4G antenna (with Three sim in a router) at my holiday home in Donegal.
    My antenna posts directly at a Three mast with clear line of sight. The mast is probably 1 or 2 miles away.
    I get a 100% 4G signal showing on the router. Most of the time my download speeds are between 1-2 Mbps and sometimes going up to 8-9 meg in non peak times. My upload is consistently between 10-20 Mbps all of the time.
    If I change to 3G I might get slightly better download speeds of 6-7 Mbps but then poor Uploads of 1-2 Mbps.

    Am I right in thinking that the good upload speeds on 4g confirm I have everything aligned pretty well and I am just at the mercy of mast congestion and probable overloading causing my comparatively poor download speeds?

    1. It is quite likely either high contention on the mast or with the backhaul to it. Even on the Kilcar mast I’m connected to (also in Co. Donegal), the speed was dipping to 1-2Mbps this evening. The off-peak speed seems low however (I’d expect 20+Mbps for a strong signal), but there could be more people connected to it than the one here. If your router shows the SINR reading, that would be a good indication of how clean the signal is, i.e. it should be as positive as possible, preferably above 10.

      I wouldn’t worry about the upload speed on 3G unless you are uploading a lot of data. 6-7Mbps should have no problem streaming even in HD, assuming it’s a steady speed. Most people leave their router and phones connected in 4G, so this usually results in better 3G speed as most people would not think of trying 3G mode.

  2. Thanks for the reply.
    Unfortunately my router interface is very basic, it just gives my signal strength as a percentage and nothing more detailed than that.
    Out of interest, if you are getting similar 4g peak times to myself, do you stay on 3g or switch between the two?

    1. The 3G reception is very poor here, worse than 4G surprisingly. If I’m outside, I can pick up 4G fine (2-3 bar signal), but if I try dialling a number, the call will always fail and similarly I cannot receive calls as calls require 3G on the Three network. If I force my phone into 3G-only mode, it just says no service. I have a StellaDoradus 900MHz repeater and a directional antenna that gives me indoor 3G reception, however, with the weak 3G signal it manages to pick up, the 3G speed is poor, but at least usable for voice calls and receiving SMS verification codes.

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