Hi Marcus,
Before I get into more details, since you did not mention which radio you have, the first thing to realize is that not all radios support GMRS repeater use or might do so only after performing extra steps. Your owner's manual will help you determine that. If you don't have a paper copy of the manual, try looking for it online on the web site you bought the radio from or the manufacturer's web site. You can also try online manual archives such as manualslib.com.
If you've determined your radio can support GMRS operation, continue reading...
In case it might help, here is some fundamental information about repeaters. Repeaters use two frequencies. The frequency that the repeater transmits on is the output frequency. Since that is the repeater's output freq, that is also the freq you'll monitor to hear what comes out of the repeater. A repeater also uses an input frequency. This is the frequency that the repeater monitors to hear your transmissions and rebroadcasts them basically simultaneously on the output freq. This is known as duplex operation and is fundamental to how duplex repeaters work.
When you see a repeater frequency listed in mygmrs, that is the output frequency that the repeater transmits on and that you monitor. But what about the input frequency you need to use to transmit to the repeater? That is accomplished via an offset. Normally for amateur radio, a + or - 5 MHz offset is used for UHF operation. GMRS is also UHF, but it uses only a +5 MHz offset for repeater use. The +5 MHz offset means that for whatever output GMRS frequency is being used, the input frequency is 5 MHz higher. In your original posting, you mentioned 462.650 MHz. You can tell this is a GMRS output frequency because it is in the 462 MHz range. (Note that there are also 462.xxx simplex, non-repeater frequencies in FRS and GMRS. The 462.xxx freqs only represent a repeater output when we are discussing GMRS repeaters.) So, for a repeater output freq of 462.650, the input freq you'll need to access that particular repeater is 467.650 (notice the 467 instead of the 462) because we are offsetting by +5 MHz.
So how is the +5 MHz offset accomplished? It depends on your radio. There may be dedicated memories which take care of the offset. Otherwise, you may need to take additional programming steps. If so, consult the manual. For my Wouxun KG-905G handheld radio, which has preprogrammed repeater memories, such memories show a "+" sign in the display to represent the +5 MHz offset. If your radio is capable of GMRS repeater operation and it is preprogrammed with the eight possible GMRS channels in memory, select the appropriate memory for use with the repeater you are trying to access. It's possible that your radio might display a repeater's freq info with a alphanumeric label such as "RPT-19." If you're not sure which GMRS output frequency that represents, consult your owner's manual. There is also a possibility that your radio has a menu selectable option that can display a memory's content as a frequency instead of the alphanumeric tag.
Let's say you've determined that your radio is 1) GMRS capable, 2) has a memory assigned for the particular GMRS repeater you are interested in, and 3) you have selected that particular memory. What's next? Access tones, aka PL tones.
Repeaters typically require analog (CTCSS) or digital (DCS) access tones. This is done for two reasons. First, since there are only eight GMRS pairs (input and output freq combinations), that means several repeaters you might be able to access locally may use the same repeater freq pairs. In that case, so that you access the repeater you're interested in, you may need to transmit the appropriate transmit tone to "open" that particular repeater. As such, if a repeater requires you to send a particular transmit access tone, that is the most important tone. But if a repeater database such as mygmrs also lists a receive tone, what about that tone? That tone only influences what you hear or if you hear anything at all. So what will you hear, if anything?
Let's take the case of a repeater that does support your use of a receive tone because it transmits an embedded CTCSS tone of say 156.7 (for example). There are three possibilities:
1) if you set your receive tone to none, you will receive/hear the transmission from the repeater in all cases. By setting your radio's receive tone to none, you are instructing your radios receiver to send the message to the radio's speaker regardless of whether or not the received transmission has a tone embedded in it from the repeater.
2) if you set your radio's receive tone to say 156.7, you will hear a repeater's transmission only if the same 156.7 tone is embedded in the transmission from the repeater. By setting a receive tone, you are instructing the radio to send a message to its speaker only for transmissions that are received which have an embedded tone that matches the receive tone you specified.
3) if you set your radio's receive tone to say 156.7, if a repeater's transmission has a different embedded tone or no tone, you will not hear the transmission on your radio.
As you can, in the case of GMRS repeater operation, your use of a transmit tone only matters when a repeater requires you to open it via a transmit tone so you can transmit to it. If you use a receive tone, that has nothing to do with opening a repeater to transmit to it. Your use of a receive tone determines only if you'll hear a message or not. So even if a repeater requires an access tone to open it for your transmission and you use the correct transmit access tone, if you utilize an incorrect receive tone, you will not hear any transmission from the repeater.
Another thing to be aware of is that some repeater's require split tones. That is, different tones for transmit and receive. This can be either two different CTCSS tones, two different DCS tones, or a CTCSS tone and a DCS tone. If you're having trouble talking to and hearing from a repeater, split tone operation and whether your radio is capable of that might be the explanation.
Earlier I mentioned there are two reasons repeaters typically use access tones. The first reason discussed earlier above was due to necessity. Since there are only eight repeater pair channels, access tones provide a way to distinguish between repeaters which share these eight channels. A second benefit of using access tones, especially transmit tones, is to try to lock out trolls/jammers. Of course, since they might discover the access tones, repeater owners occasionally change which transmit tone you'll need to access the repeater again. As such, if you were able to open a repeater previously but now can't, this is the first explanation to consider. If so, you'll need to find out what the new access tone is and update your radio. Do not share such info publicly in forums - otherwise you will let the trolls/jammers know about the new tone.
Another thing to be aware of is how various radios are programmed differently. The most flexible radios allow for total programming via their keypads as well as via PC software and programming cables. The least flexible radios require most if not all of their programming to be done using PC software and a programming cable. Other radios fall somewhere in the middle. For example, to program frequencies in free memory slots in my KG-905G, I must program those freqs via a PC/cable. But once those freqs have been programmed in the memories, I can change the characteristics (e.g. high/low power, receive tone, transmit tone) of the freqs via the radio's keypad. I cannot stress enough how nice/important it is to be able to change such parameters in the field untethered to a PC and cable. Though it's not in the scope of my answer to the original question to go into purchase decisions, for anyone considering buying GMRS radios, do your homework regarding must-have/desirable features. Otherwise, in an attempt to "save money," you might find yourself buying multiple radios instead of the right one from the get go.
Especially if all this is new to you, I know I've provided a lot of info. If needed, it might help to digest it in bite size pieces, a paragraph at a time. Hope that helps. Happy radioing.
