Although DMR has been around for a while it is still the new hot-topic in ham-radio. The cost of equipment is the lowest we have experienced in the hobby with numerous Chineese radios which are really good and competitive on features for less than $100. Additionally, the first generation of repeaters are now on the used market at affordable prices.
On the following pages, I will give a basic overview of the N1ATP DMR Network system as well as a glimpse of Brandmeister DMR Network.
Before reading on, let’s remember that DMR was developed for commercial use with a limited number of users and was never intended to have a user ID list well over 100,000 as we now have. Thus, some limitations are yet to be overcome.
Below are the recommended simplex frequencies to be used with DMR in Canada and the United States. In addition to this information, please note the following radio configuration items:
| FREQUENCY | BAND | TALKGROUP ID | TIMESLOT | COLOR CODE |
|---|---|---|---|---|
| 441.0000 | UHF | 99 | 1 | 1 |
| 446.5000 | UHF | 99 | 1 | 1 |
| 446.0750 | UHF | 99 | 1 | 1 |
| 433.4500 | UHF | 99 | 1 | 1 |
| 145.7900 | VHF | 99 | 1 | 1 |
| 145.5100 | VHF | 99 | 1 | 1 |
I would assume we will not use these frequencies for our HotSpots. Many HotSpots default to a frequency in the satellite band and although the HotSpot is at less than 20mW, the HT typically will have higher power. HotSpots have supposedly interfered with satellite communications. So what is a good frequency?
My HotSpots will be nestled in-between other other frequencies. Close, but not in a weak signal band.