The Countryside Alliance is asking people to become phone detectives this summer and help it map real phone reception rates across the UK and Preseli Pembrokeshire Assembly Member, Paul Davies is behind the cause.
Mr Davies said: "Everyone pays the same for their phone package but phone reception is variable and some people are not getting a good deal.
"The Welsh Government and phone companies need to take notice of this fact and ensure that no one is missed out from the mobile network."
The Countryside Alliance is asking people to download the free RootMetrics app onto their smartphone or tablet and use it while they are at home as well as while they are out and about.
The app tests the strength of their signal and automatically records the result. It can also be used to check which company provides the best service in an area.
The information will be used to lobby phone companies and the Government to improve mobile reception, especially in isolated rural areas.
Mr Davies added: "I would ask everyone to download the app and make use of it this summer so the Countryside Alliance can have the best possible information to take to the Government and phone companies this autumn."
