Hello, right now I have a super basic Motorola W385 phone. I bought this phone for it's antenna, not features. I work at various construction sites all over Colorado and at many of these out of the way places I am the only one on site that is able to complete a call. I can stand next to someone with a Verizon iPhone and they don't even receive a signal while I can talk without an issue.
I am looking to move into the smartphone world so I can send/receive emails as well but I need to know which phone has the best antenna/reception on the market. I don't care what size screen it has or if I can play angry birds or post to facebook about the great time I am having. I just want to be able to reliably make a call and send/receive email. A phone with a hard keyboard would be fine, does not need to be a complete touchscreen. Also, don't tell me the phone doesn't matter.. It does, they are all designed differently and utilize various antenna designs so it makes a huge difference.
I have an old W385 flip phone which was my last basic phone before switching to a smartphone. I will have to agree with that phone had a great antenna.. I don't have a recommendation for you on which smartphone would work best for you. I can say that I seemed to have better voice calls with my HTC Thunderbolt then I have had with my Samsung Galaxy Nexus.
Maybe it would be a good idea to note down which phones you have seen in your job where they don't get signal. That way you can rule those out first and start looking at the phone models that remain.