With repeater radios, all transmissions are from the person talking to the repeater and from the repeater to the people listening.  Since one end (the repeater) of the transmission is fixed at a particular location, the range on the radio is defined by the location of the repeater.  If your radio performs properly, you will get the full range offered by the repeater.  If your radio has some performance issue, the repeater will appear to have “reduced range” because your radio decreases the ability of the repeater to hear your signal or the ability for you to hear the signal from the repeater.  With portable radios, change radio, change battery or change the radio antenna.  With mobile radios there can be a problem with the vehicular electrical system so the radio does not get the appropriate power.  Also, it is possible for the radio antenna to have a problem from being broken off, stolen, shorted, open or partially unplugged.