- January 10, 2019 at 10:08 am #108668
Total posts : 268
There has been some discussion about “Free Radiate” systems and how far a signal can emanate beyond the boundaries. The attached file is the University of South in Tampa. This Part 15 station operates under 15.221. Note the FCC Rules are vague with regard to the definition of a “perimeter.” Now we all know what a perimeter is, but do the rules apply exactly at the perimeter or some distance out? Also as you can see in the image the campus is not a square and if the signal was measured “at” the hard perimeter there would not be a usable signal withing the campus boundaries at those points. I am told the transmitter/antenna was installed by the College of Engineering. The station has been in operation for years with a listenable signal in a car about 1 mile in any direction. BTW, the former Tampa Enforcement Office was about 5 miles as the crow flies from the campus.
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- January 10, 2019 at 11:18 am #108674
Total posts : 1541
After Due Deliberation
I’ve thought about the situation for close to a minute and think the engineer could pick the perimeter farthest from the transmitting antenna as the useful measurement point.
- January 10, 2019 at 7:31 pm #108682
Total posts : 391
This dam thing.. I made a reply and then came back to edit a spelling, and it appears to have deleted my post, so since it was still on my clipboard I tried to post it again but it just says:
ERROR: Duplicate reply detected; it looks as though you’ve already said that!
Yeah, well I know that, but it’s not posting the first one!!
- January 10, 2019 at 7:34 pm #108683
Total posts : 391
Lets try it again…
Well I think it’s based on the readings at the perimeter, which I guess would read differently on different occasions because environmental conditions can change those kind of readings from day to day. Maybe it was within the readings at time of install.
As far as defining the perimeter boundary when it varies with direction, I agree, pick the farthest perimeter and base it on that. As for being listenable a mile with a car radio, first there’s the question of defining “listenable” and secondly how consistent in all directions and on any given day it is.
As far as opinion goes from a more legal perspective, no it doesn’t sound like they are conforming to the letter, well, as I’ve expressed before, if all our installs, and the FCC certified part 15 transmitters themselves complied to the actual letter of the law then no part15AM transmitter could feasibly achieve more than a few hundred feet range.
If ALL the rules concerning part15AM were followed exactly, then 15.221 would by far be the one which has the greatest range capability.
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