Lets get back to basics, coax cable has two main characteristics. In simple terms, one is the impedance of the cable and the other is the loss of the cable at the frequency in question.
The impedance of the cable should match the impedance of the equipment
. Most radios require a 50 ohm cable. Most TV systems require 75 ohm cable. Satellite
systems are a bit of a mixture, some require 50 and some require 75.
The loss is easier, the longer the cable, the greater the loss for a given cable. Note that the loss is also frequency dependent.
So in your setup where you want 30' ft of cable, I suggest a reasonably low loss cable (but not an extreme low loss). However I can't tell if you need 50 or 75 ohm cable without knowing either the make/model of the system or the type of existing cable.
Sometimes (but not always) the connectors can give one a hint as to the cable spec.
So what is the make/model of your satphone and do you know what connectors are being used?
For the record
, RG 58 is 50 ohm coax while RG 59 is 75 ohm coax. Both are relatively high loss.