My new MMDVM DMR hotspot shipped with a little SMA antenna, and has a power output measured in milliwatts. I wanted to figure out just what kind of effective range I had for it, so that I could get away from my desk while connected to it.
My radio is a DM-5R with low power at 1 watt and high power at 5 watts. At about a block away from home, transmitting on low power, I can get a clear echo reply to my hotspot with Parrot. At four blocks away, the low power TX doesn't get into the hotspot, but my RD-5R still picks up some fraction of activity on an active channel.
The next test was to change to high power (5 watts) on the radio, and to get a better antenna setup for the hotspot. I have a 2 meter ladder line antenna that also works on 440, so I connected that up to the SMA port to see how it would work. My best distance was about 137 meters, as measured by GPS, from my house to the bus stop. That's almost line of sight with just one building in the way using high power (5 watts) on the RD-5R into the hotspot, and Parrot to verify transmissions.
Some other DMR range experiments from Youtube:
- K0LWC measured 0.7 miles (1100 meters) with an Anytone 878 into a 10 milliwatt hotspot, with clear line of sight across a park and no buildings obstructing his view.
- KG4VDZ hooked up a SharkRF OpenSpot 20 milliwatt hotspot to a 50 watt amplifier, and claims a DMR range of 15 miles using a vertical antenna on top of a tower.