DMR Simplex Channels

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K6GBW

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This may have come up before, but I don't know of there is a definitive answer. I use DMR quite a bit on 70cm. When I search for DMR simplex frequencies I get a few that keep coming up, but they are not confirmed. My local band plan is kind of nebulous on the matter and shows only "Digital Experimental" frequencies. I absolutely don't want to use DMR on 446.000 or 446.500 because frankly, DMR on a channel being monitored in FM is obnoxious. I found some evidence to suggest that 441.000 and 441.500 MHz are common DMR simplex channels. Does anyone have anything that backs that up or have any other information?

BTW, I'm in SoCal.


Thanks,

Brian
 

bharvey2

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I was an early adopter of ham DMR. 441.000 and 441.500 are two frequencies that seem to have been commonly associated with DMR simplex although I can't say I've ever heard of any formal decree saying those are dedicated to DMR. - Best I can do. (BTW, I see you spell your name with an I. Good man)
 

vagrant

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441.000
441.500

I think “any“ digital mode would be fine sharing those two UHF frequencies for simplex. Well, at least in central and northern California.

One of the VHF freqs in those links is used by SSTV, yes still used here, and the other reserved for satellite. Unsure what to use on VHF as what may work here could be a problem elsewhere.
 

AK9R

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Both of the linked sites list these frequencies:

441.0000
446.5000
446.0750
433.4500
145.7900
145.5100

The following are snippets from the unofficial, gentlemen's agreement band plan posted on the ARRL website:

1721308647653.png
1721308667311.png
1721308696934.png
1721308732504.png

It would probably be best to check with your local repeater coordination group to see what they suggest as a local band plan.
 

K6GBW

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Thanks to everyone. I found a recently added document to SCRRBA (the frequency coordinator for California) that shows digital simplex frequencies disignated in the 431.0125 to 431.100 MHz area. It specifically shows 441.000 MHz as being a remote control frequency and says "No voice or Digital"...the other frequencies shown are also for other uses. I can only assume that in California the use of digital simplex is different that in other areas.
 

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vagrant

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@nd5y - Do I have proof? Relax…take is easy…it’s just a digital simplex frequency topic. I even created a second paragraph as I was then noting VHF. I invite you to review the “VHF” band plan the coordinating body for my area has posted. It would be nice if we could have a few common digital simplex frequencies across the U.S., but regional (coordinating body) solutions should be fine. My digital radios have plenty of memory slots, but I don’t plan on visiting every state in the U.S.

@K6GBW - Once you come north out of SoCal RF hell, you can enjoy NARCC.org which handles the rest of California. Here is the NARCC coverage map.
 

K6GBW

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Yep, we ARE different down here! I'm glad I found that SCRRBA document before I started using those other frequencies. I guess 441.000 is used to remote control repeaters. I'd probably make a bunch of people cranky.
 
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