New to GMRS. Question about repeater channels

[RadioJK13]

Hey gang,

 

Need some info. I purchased a Midland MXT275 radio for my jeep. everything is set up. works great. the question i have involves the repeater channels. so on the radio when you turn on repeater channels such as CH 15 with runs on 462.550. As i understand it on the repeater channels it transmits on that same freq and receives on another freq. ok makes sense. if i dont turn on the repeater channels and just use CH 15 will people that still transmit to a repeater? Or is it seperate from the repeater channel?

 

hope this all makes sense.

 

thanks for any help.

 

Wayne

[berkinet]

...on the radio when you turn on repeater channels such as CH 15 with runs on 462.550. As i understand it on the repeater channels it transmits on that same freq and receives on another freq. ok makes sense. if i dont turn on the repeater channels and just use CH 15 will people that still transmit to a repeater? Or is it seperate from the repeater channel?...

If you transmit on a repeater channel you will receive (listen) on the channel displayed (462.550 in your example) and transmit on another frequency exactly 5.0mHz higher. (467.550 in the case of your example.)

 

If you are on a simplex (non-repeater channel) you will transmit and receive on the same frequency. (462.550 in your example.)

 

There is a problem with the radio nomenclature where the word channel is used with two different meanings. First, the FCC has designated 30 UHF frequencies use. For convenience sake, each of these frequencies is assigned a channel number: 1 to 22. The 8 frequencies reserved for repeater inputs are grouped with the corresponding receive frequency so there end up being only 22 channels numbers. As noted above, whether you transmit on your receive frequency or the repeater's receive frequency depends on how you configure your radio.

 

Now, radios also have arrows, dials or some other means of selecting the frequency, and these selections are also called channels. How channels are assigned in the radio differs from manufacturer to manufacturer even model to model. Some vendors of FRS radios call each combination of a frequency and a PL tone a channel.

 

Hope this helps.

[Ccleveland1226]

When you have the mxt275 on channel 15 without the "rp" repeater icon it will transmit & receive on 462.550 . When you select the repeater channel 15 (with the "rp" icon) you will continue to receive on 462.550 but transmit at 467.550 . What that means is that you can still receive and hear traffic from a repeater on the non-repeater channel, but when you transmit the repeater will not hear you because it is looking to receive at the 467.550 . Without the frequency separation used in repeater "rp" mode, nobody on the repeater will hear your transmission except any station that is within direct simplex range of your transmission.

[Ccleveland1226]

That is also assuming no Dcs (privacy codes), dcs codes are used to filter out incoming traffic so you hear only the traffic you want to. Pretty much every repeater has some sort of Dcs code configured on it's receive frequency.

[RadioJK13]

thank you for the info. make sense. 

 

appreciate the help.  

[quarterwave]

"Channel" makes me think of Crystals. I call OTA TV, "Channelized TV" whereas Streaming TV is not, it's more like a browser or free form.

 

Another way of thinking of the non-repeater mains in these radios is "Talk around" (long used in commercial service) because you talk around the repeater (bypass) it...or simplex. So if someone is on that frequency using a repeater (and same DPL/PL) you could still hear them (the output of the repeater) and they could conceivably still hear you transmitting on simplex if you are close enough to them. You generally have a couple of very radio-wise operators on the air if this is going on. Same with reverse pair...but we won't get into that.