- November 2, 2018 at 3:02 am #107078
We have a potential grant to purchase a TR6000 Model 15.73 and ANXX Antenna to operate under § 15.221
Before I ask to spend non-grant money on hiring a professional RF engineer to do the measurements, I wanted to make sure I understand the regulatory.
§ 15.221 (2) states: At the perimeter of the campus, the field strength of any emissions, including those within the frequency band 525-1705 kHz, shall not exceed the general radiated emission in § 15.209.
Our campus is irregular in shape, crosses streets and involves a river. How would you calculate the perimeter?
- November 2, 2018 at 4:49 am #107080
After many years of part 15 discussion, spareparts has asked the one question I don’t believe anyone has ever asked before: “Our campus is irregular in shape, crosses streets and involves a river. How would you calculate the perimeter?”
When drafting 15.221 we think the FCC had in mind a perfectly round campus.
This will be an interesting thread to watch if anyone is bold enough to venture an answer.
- November 2, 2018 at 6:04 am #107082
If your campus has any across-the-street parking, an annex, a steam/power plant or admin building a bit of a distance away from the main grounds, that may help a bit in “rounding off the corners”.
Otherwise, for a question like this, it might be worth your while to sign on with one of Barry Mishkind’s pro broadcast forums (found at radiolists.net) and throw the question out to the crowd there. In all likelihood someone there has already done it, so you need not have to reinvent the wheel.
- November 4, 2018 at 6:41 pm #107116
Answer courtesy of Mark Mueller • Mueller Broadcast Design
Not exactly what I was looking for as it basically cuts away 2/3 of the campus.
- November 5, 2018 at 2:27 am #107118
- November 5, 2018 at 2:49 am #107122
NOTE regarding my post above: Some of the assumed 85mW of output power is dissipated in the radial ground system. Those effects are included in the mileages shown for various Earth conductivities, in the table.
- November 5, 2018 at 11:15 am #107126
How are your own engineering chops? Can you park the transmitter/antenna close to one end of the campus and put a passive antenna some distance behind it? You are essentially creating a short-form directional array to beam the signal straight down the heart of the campus.
Or is that illegal?
- November 5, 2018 at 2:08 pm #107128
BillyBurg On Legality
” Is that illegal?”
Yes, BillyBurg, I would maintain that the antenna arrangement you described would be FCC legal by the simple fact that it is not disallowed anywhere in the Rules.
RF measurements at the property line are the single test of compliance.
You must be logged in to reply to this topic.