Class A10 FM Petition For Rulemaking

[Ben Zonia]

Class A10 proposes a new FM Class with greater than 6 kW up to 10 kW/100 meters.

The proposal for Class C4 FM has been held up for around 10 years. I suspect this proposal will also encounter tough sledding.

It looks a little short on details other than the distance separation table.

This proposal does allow stations in Zone I to upgrade (as well as in Zone II), or below 43.5 degrees Latitude in Michigan, whereas the Class C4 stations with up to 12 kW/100 meters were restricted to Zone II, or above 43.5 degrees Latitude in Michigan.

When you get right down to it, few stations are usually able to benefit from these types of proposals. The band is already jammed up.

https://www.fcc.gov/ecfs/document/10613442608521/1

Radio World Discussion

https://www.radioworld.com/news-and-bus ... -for-radio

They might better go back to pre 1964, service and interference contour overlap based rules, like the Reserved 88-92 MHz NCE-FM band continues to use. It would maximize the possibilities. These are available in old CFR 47 Part 73 FCC rules (it was Part 3 then as I recall) and in the 1960 NAB Engineering Handbook, available on worldradiohistory.com.

https://www.worldradiohistory.com/Archi ... tion-2.pdf

[Ben Zonia]

FCC Seeks Comments. Due dates for Comments and Reply Comments.

https://docs.fcc.gov/public/attachments/DA-24-583A1.pdf

[Ben Zonia]

In the 1960 NAB Engineering Handbook, FM Rules start on Page 1-125. Interference ratios are shown on Page 1-148.

Service Contours are predicted by F(50,50) Curves. Interfering Contours are predicted by F(50,10) Curves. Revised for dB vs. mathematical ratio.

0 kHz 20 dB D/U 10:1
200 kHz 6 dB D/U 2:1
400 kHz now -40 dB D/U 1:100
600 kHz -40 dB D/U 1:100

[Ben Zonia]

Meanwhile, many Class As are still stuck at 3000 watts, many in more populated cities and areas in Michigan.