Subject comparisonCoverage compared
How to find out what actually happens at your address.
Photo from a free stock library — illustration only.
Important notice: keyanok is an independent information site. We are not a mobile network, and we are not affiliated with, endorsed by or connected to Three, O2, Sky Mobile, EE, Vodafone or any other provider. We do not sell SIM cards, contracts, handsets or services of any kind. Every comparison here is general guidance and opinion only — always confirm current details with the provider's own website or app before deciding anything.
Evidence — coverage maps vs a trial month
Coverage maps
Computer models of predicted outdoor signal from terrain, mast positions and transmit power.
- Free and instant
- Useful as a first filter
- Cannot know your walls
- Cannot show congestion
VS
A trial month
A rolling SIM on the target masts, lived through an ordinary week.
- Reflects your actual rooms
- Includes rush hour
- Costs pocket money
- Takes a month
Which wins, and for whomUse both, in that order. Maps rule places in and out; only a month at your own address decides. Run the network's checker and Ofcom's, weight indoor predictions, then test.
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Call 020 3896 5248WhatsApp usProblem — weak coverage vs congestion
Weak coverage
Few or no signal bars, usually indoors or rurally.
- Building materials and distance
- Wi-Fi Calling is the remedy
- Shows partly on maps
VS
Congestion
Full signal bars with nothing loading.
- Too many handsets on one mast
- Peak hours, stations, venues
- No setting resolves it
- Invisible on every map
Which wins, and for whomDiagnose by symptom, not by bars. Switching network fixes weak coverage and does nothing for congestion — which is why the rush-hour test matters as much as the postcode check.
Testing SIMs by landlord
On O2giffgaff or Tesco Mobile
On ThreeSMARTY or iD Mobile
On EE1pMobile
On VodafoneVOXI or Lebara
Free indoor remedies
Wi-Fi CallingRoutes calls over your broadband so walls stop mattering — free, and off by default on many handsets
4G Calling (VoLTE)Required since the 3G withdrawals of 2024 and 2025
PositionOne metre toward a window materially changes reception
RepeatersUnauthorised equipment can interfere with the network — ask your operator about approved options
Re-checking
Masts are built, upgraded and re-farmed continuously, and the VodafoneThree consolidation is actively redrawing the national picture. An address that failed a year ago may pass now.
Re-run both checkers annually, and always on a new postcode before exchanging on a house — signal is far easier to verify than to remedy.
Important notice: keyanok is an independent information site. We are not a mobile network, and we are not affiliated with, endorsed by or connected to Three, O2, Sky Mobile, EE, Vodafone or any other provider. We do not sell SIM cards, contracts, handsets or services of any kind. Every comparison here is general guidance and opinion only — always confirm current details with the provider's own website or app before deciding anything.