AMSAT recently made known an interference problem to the amateur satellite service caused by a DMR signal:

This week, AMSAT News Service (ANS) cited an August 27 report from AMSAT Vice President-Operations Drew Glasbrenner, KO4MA, saying that a digital mobile radio (DMR) signal has been interfering with the AO-92 (Fox-1D) satellite’s 435.35 MHz uplink frequency. Glasbrenner said hotspots, repeaters, terrestrial simplex, and “anything not satellite” should never transmit in the segments 145.8 – 146.0 MHz or 435 – 438 MHz by international band plan.

Since repeater frequencies are generally coordinated, the problem is a result of the proliferation of “hotspot” devices that provide network connectivity on a local level. Despite these incorporating ultra low-power transmitters, their use requires that the radio being used in conjunction with them be set to the same frequency.

So while your hotspot may only run 40mW and seem benign, the radio you use to interact with it will most certainly utilize higher power. In addition, one of the first questions asked by most new hotspot users is, “how can I connect my hotspot to an external antenna to extend its range?”

And then consider that the most popular such device, the openSPOT, shipped with a factory default frequency of 436.000 MHz.

If AMSAT’s gentle suggestion to clean it up and get with the bandplan isn’t enough to spur you to action then perhaps the fact that there are multiple online services reporting your hotspot frequency to the entire world right this minute, even as you read this, might shame you into action.