A) Can I access this repeater w/o the offset ?
B ) Does the Midland Mobile automatically generate the needed offset ? (It's just not indicated in the manual?)
C) Assuming the repeater owner will permit me to use his/her repeater, can I use the repeater in a simplex mode ?
D) Is the intent of having an offset to prevent low cost GMRS owners from using a repeater even if they know the needed access code. (Thereby limiting use to more expensive radio users ....i.e. Motorola radios, etc.) Reducing traffic being the intent.
E) Can a GMRS repeater automatic function in a delayed simplex mode when it determines that a offset operation is not possible.
A) No. GMRS repeaters operate with set input and output frequencies offset by +5 MHz. For example, 462.600 has an input frequency of 467.600 and an output of 462.600. The user's radio transmits to the repeater on 467.600 and receives on 462.600. That means that any simplex GMRS radio can hear the output on 462.600 but will not be able to open the repeater because it is not transmitting on 467.600. One cannot properly access the repeater without the offset between transmit and receive frequencies.
B ) Yes. The models that are repeater capable will automatically use a +5 MHz offset when rP is selected.
C) No. One cannot properly use a GMRS repeater without the offset. The repeater will never receive the signal if it is not transmitted on the input frequency, 467.xxx.
D) No. The offset is to allow the repeater to function properly. As such, it needs a separate transmit and receive frequency with enough offset to be able to filter out the other. There are parrot repeaters (store and forward) that use one frequency. A user transmits to the repeater. The repeater stores the audio and then transmits it back on the same frequency. It can be a pain to use and I'm not sure it is permitted in GMRS but I have heard a few on the air. As to the code. That's a sub-audible tone (we can't hear it but the radios can) used for squelching. Instead of having to set the carrier squelch of the repeater above a changing noise floor, tones allow the repeater to only open when the proper tone is transmitted. Although it also functions as a simple gateway for repeaters, there aren't that many tones and they can be easily captured by scanning or even guessed at.
E) Not really. One could be designed to do that, I suppose. But, it would be a royal pain for users. It would get very confusing in a hurry for the users as to which was stored and forwarded (simplex) traffic and which was not. Anyone close enough to receive the originating signal would not know if they were hearing the sent traffic or the repeated traffic. For such a mode, one has to wait for the originator to finish and the repeater to spit it back out.The tried and true method of two frequencies and an offset works very well. I wouldn't expect most repeater owners to even go through the hassle to set a Frankenstein like that up and I'm not sure how many users would use it given the high potential for confusing and aggravating operation.
Regarding Midland Micromobiles and repeaters...We have noticed a significant problem for some of our local users running Midland Micromobiles. I am told that they apparently cannot set the repeater frequencies to tone transmit and carrier squelch. If it transmits a tone, it requires the same tone on receive to open the squelch. The GMRS repeaters we have around here, and in all other places I've used them, do not necessarily output a tone per se. They rely on the transmitted signal from the user to contain the tone. The repeater just passes the audio through. That gets to be a problem when repeaters have multiple tones to access them like many I've used. If someone is accessing the repeater with a tone different than the Midland, the Midland will never hear the traffic. Likewise, if a Midland user is listening for an open repeater to use, they will never hear already existing traffic using another tone. The Midland user will end up unwittingly transmitting with the other user. The work-around local Midland users have been doing is listening to the repeater output on another radio with carrier squelch (no tone). That is the only way that they can avoid talking over someone with a different tone and hear responses from users transmitting a different tone. Midland may have fixed that already or not. These radios were recent purchases (within the year) so I suspect that Midland has not addressed the issue.