The email blast from the head of my son and daughter's theater group relayed a frantic plea: "We need to raise $16,000 before the upcoming spring performances," Anya Wallach, the executive director of Random Farms Kids' Theater, in Westchester, New York, wrote in late May. If the money didn't materialize in time, she warned, there could be a serious problem with the shows: nobody would hear the actors.
Random Farms, and tens of thousands of other theater companies, schools, churches, broadcasters, and myriad other interests across the country, need to buy new wireless microphones. The majority of professional wireless audio gear in America is about to become obsolete, and illegal to operate. The story of how we got to this strange point involves politics, business, science, and, of course, money.
Story: https://www.wired.com/story/wireless-mics-radio-frequencies-fcc-saga/
(Score: 2) by RS3 on Tuesday August 14 2018, @05:35PM (1 child)
Yes, I remember 100mW being the spec, but memory can be flawed. I intentionally omitted it because 100mW at 100KHz will carry much farther than 100mW at 32GHz, with similar antenna gain of course.
But even with a 200 foot rule, there's still some power at 200 feet, so how do you decide that it's low enough so as not to interfere with an average receiver?
My point is that in practice, the 700 MHz band wireless stuff should not be a problem and people should be allowed to continue using it until someone can measure a problem, which is pretty easy to do with a simple field strength meter. FCC worry that it will interfere with emergency services, but I'm skeptical.
Typical UHF wireless microphone systems are 50 mW https://en-us.sennheiser.com/wireless-microphone-live-monitoring-system-ew-300-iem-g3 [sennheiser.com]
(Score: 3, Informative) by All Your Lawn Are Belong To Us on Tuesday August 14 2018, @10:40PM
Very true, all.
I did just a little more digging on that page and it said that the 1991 technical notice is still actually in effect and had a link to it. The notice (which is probably what we remember) also specifies: AM 100mW to final RF and .05W ERP and FM .01uW ERP with actual spec of 250uV/M measured at 3 meters, in addition to the 200 foot maximum coverage radius and that reads more like it's cannot be picked up by any receiver at 200 feet away, period. (Also says TV is not allowed at any time).
And aside from that, it is Part 15.5 that additionally imposes the requirement that the device cause no harmful interference and that the device is disabled upon receiving a complaint from the FCC that it is causing interference, and that's aside from all the other rules.
So I guess all the old rules still apply as well.
This sig for rent.