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The FCC Wants Noise Floor Data (Docket 16-191)

W

Willits

Frequent Participant
The FCC is looking for quantitative noise floor data (ET Docket No. 16-191). Does anyone have any? There certainly appears to be a problem of the noise floor increasing, but the FCC wants to see data. Taking such data today might be fairly straightforward, but it appears they want historical data as well. Qualitatively, there seems to certainly be an increase. For example, here is a link to an aircheck of KOMA in Oklahoma City taken in 1964, at night from South Dakota. Partly because of its high frequency (1520 kHz), there are deep signal peaks and valleys. On the valleys, the spectrum is far quieter than it would almost certainly would be today, I'm pretty sure. And overcoming the noise floor to produce an intelligible signal required less strength than it would today, most likely. While South Dakota is not exactly downtown Philadelphia, on the nulls the spectrum is ghostly quiet.

https://www.youtube.com/watch?v=vQHPEFw0zHI
 
Willits said:
The FCC is looking for quantitative noise floor data (ET Docket No. 16-191). Does anyone have any?
Click to expand...

Over the past 20 years? Sure, I've got all that information that right, here. Or did I leave that over there? Hey, they only want data over the "Radio Spectrum"? No problem.
 
Kelly A said:
Over the past 20 years? Sure, I've got all that information that right, here. Or did I leave that over there? Hey, they only want data over the "Radio Spectrum"? No problem.
Click to expand...

LOL! It's not something everyone would have, but this board is widely read. SOMEONE out there might have some.
 
I guess we're talking about AM... right?
 
Willits said:
For example, here is a link to an aircheck of KOMA in Oklahoma City taken in 1964, at night from South Dakota. Partly because of its high frequency (1520 kHz), there are deep signal peaks and valleys. On the valleys, the spectrum is far quieter than it would almost certainly would be today, I'm pretty sure. And overcoming the noise floor to produce an intelligible signal required less strength than it would today, most likely. While South Dakota is not exactly downtown Philadelphia, on the nulls the spectrum is ghostly quiet.
Click to expand...

That's probably due to the receiver's lack of sensitivity more than anything else. I have a Hallicrafters S-38C from the 1950s which seems to have a very low noise floor, but that's really just because it's not a very sensitive receiver; it's just an All-American Five table radio with shortwave coils and a BFO added.

I'm pretty sure the USA has (and probably always had) more AM stations per capita than any other country, and the FCC allowing the band to be clogged up with "graveyard channel" stations and "flea power" nighttime signals on the former clear channels certainly hasn't helped. Across the pond where the band is a lot less crowded, it is still possible to get some impressively clear 500+ mile skywave reception, even in wideband C-Quam AM Stereo:

https://www.youtube.com/watch?v=YMAPKTnJtnA
 
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