It seems to be getting harder and harder to find newer cell phones that have RF ports (a usable one anyway). Without the RF port, you will be unable to attach an external antenna to it.
A phone may have a usable port buy the port may be too weak to support an external antenna adapter. An adapter can’t be made to stay in the port or the port is too weak and may break if an adapter is plugged into it.
So what are our options?
Wilson SignalBoost Universal Cellular Amplifier
Basically, find another phone or use a universal amplifier that has enough gain to transmit an improved cellular signal through the phone’s case.
If you’re service provider doesn’t offer a phone with the features you like that has an RF port, you can try and find maybe a used or refurbished one. Just make sure it will work with your service provider before you make the purchase.
Univeral cellular amplifiers like the Wilson SignalBoost Universal work in a similiar fashion as using an external antenna adapter. The difference is that instead of plugging in the adapter to a phone’s RF port, the adapter attaches to the cell phone by use of a universal adapter and velcro tape. The amplifier must have enough gain to transmit the signal through the phone’s case so a directconnect type of amplifier will not have enough gain.
Another option using cellular repeaters. A basic setup is to have an outside antenna and inside antenna both connected to a cellular amplifier. The amount of coverage you will get from the inside antenna will depend on the signal strength outside and the gain of the amplifier.