There is much more to 'using a repeater' on GMRS than 'buying a bubblepack that can use repeaters'.
1) Locate a local repeater which has coverage of the area you want. (Good luck... there aren't many repeaters around)
2) If you find one, determine who runs it, and whether you'll be allowed to use it. ALL repeaters on GMRS are private, and require permission to (legally) use. The repeater owner is required to keep a written record of all Calllsigns/Stations allowed to use the repeater
Many repeaters are for the use of specific, restricted groups, and not open to general use.
3) If you now have a a repeater found that covers the area you want, and are allowed to use (there may be a fee, by the way), THEN you find out from the repeater owner what tones or other access means you need. Repeaters intended for general use tend to use single CTCSS tones, in the common group of those available to bubblepacks. Other repeaters deliberately do NOT use the 'common 38 CTCSS tones' that bubblepacks offer. There are at least 42 CTCSS tones recognized by commercial gear.
Really hostile repeaters will use 'split tone', where you must transmit/recieve a different CTCSS/DCS tone on the transmit and recieve channels to use the repeater.
Example: San Diego County. I know of 6 repeaters, there may be a 7th. The 6th and possible 7th are 'REACT' operated machines, on simple common CTCSS. Neither of them has any useful coverage of central San Diego, they're in the outer areas. The 5 repeaters with good coverage of San Diego are operated by a News Stringers group, and accessable only to that group's members. Split tones are used to keep pirates off.
In this area, if you wanted a 'repeater' for your bubblepack, you'd have to install one yourself, somewhere. This can be quite expensive. (Good radio sites can charge $1000/month for rackspace for a repeater around here).
Now, after all this, bear in mind the FCC's newly proposed rule changes appear to remove repeater use from GMRS completely. In a year, there may not BE any repeaters. Spending serious money on accessing one might be not a great idea till that gets cleared up.
:lol::lol:
n9zas