The BBC has not attempted to balance the participants either geographically or by service provider.
Each box on the map indicates the average reception within that area over the survey period.
After months of tweaks and updates, the unlimited plans from all four of the major mobile carriers in the US seem to be in a relatively stable place.
But, per usual, all of those plans still come with a significant slate of caveats.
Tom Reynolds on Twitter added he has noticed a difference since the 4G switch-on: 'On 3G, sometimes Twitter, Facebook and internet is slower than usual.' Although adds that this may be due to his handset.
In July, the BBC asked people to join a survey of the UK's mobile phone coverage by downloading an app for Android phones.
During three weeks over the summer, 44,600 people allowed their mobile coverage to be tracked for our 3G survey.
The map is not intended to replace the service providers' own coverage maps when making a decision about taking out a mobile phone contract.
A study by Ofcom says 4G speeds in the UK are slower than promised.Ofcom’s research compares the speed and geographic coverage of the networks and puts EE, which is the subject of a £12.5 billion (.5 billion) takeover by BT, on top.