mobile external antennas

Samsung C5220 accepts an external aerial and is a "blue tick " phone....the external aerial that I have also connects to the Telstra "elite" nextg modem that I use on the computer...the phone can also be used as a modem....do not know about the 6db or better bit , just that it works o.k. when we are camped along the Murray river...cheers

Its worth thinking thru what your whole goal is Itzgonow.

Noting wrong with C5220 but the external antenna connection is weak , and may not last long if you use the phone mobile.
One of mine was in a standard aftermarket holder and when car went into a deep rut , phone came out and was held by the external aerial connection which promtly pulled the socket off the phones circuit board.

The connection would only be good for less than 100 uses anyway and the awkward positioning of it on this and similar phones makes it hard to use.

So if using it 4wding and you leave the car and wish to take phone its a bit messy.

The classic 6120 was being sold off cheap recently also , it has no ext ant , but performs about 3db better anyway.
If used with a passive coupler for ext connection ( about 3db loss over direct connection) then you get about the same mobile performance but its significantly easier to take shopping etc.

Nokia 6120 classic, works really well both as a phone and modem, we've done both. Force make a cradle which allows in car charging, data connection and an inductive connection to the antenna of your choice.
We also use a bluetooth handsfree unit.

I use the a Telstra ZTE 165 series phone which has a pop up antenna and antenna external port. Via the external antenna we have been getting reception in areas where all else has failed. I use this phone as a Pre-Paid emergency device as my normal phone is an Iphone. There are various 7-9DB antennas with patch cable to suit a wide range of phones.