(TAC) NOISE FLOOR TECHNICAL INQUIRY ET Docket No. 16-191

Over in the UK we've had a working HF noise measurement system for some years.

Details on the RSGB noise measurement campaign:

http://g4fkh.co.uk/projects/noise-measuring-campaign/

Details on the receiver and software program:

http://www.crosscountrywireless.net/noise_measurement_program.htm

Regards,

Chris, G4HYG

 

I'm really surprised at some of the negative reactions by hams to this effort by a group of engineers and technicians to help the FCC confirm that there is a problem with a growing ambient noise level.

Anyone who has had a receiver operating in a urban or suburban location over the course of several years likely has experienced problems of interference from man-made noise and can see the increase over the years. Even people in rural locations suffer from the noise generated by their own consumer electronics!

See one of my professional presentations on this topic...

http://www.wd8das.net/Radio-noise.pdf

It shows an example of how one can approach the problem of measurement - comparing various locations. It also points out some common offending systems and devices.

Steve WD8DAS

 

I have ceased to be surprised by the reflexive negativism of some folks. Whatever.

 

For me, it seems like the ambient man-made LF/MF/HF noise level has actually been reduced in many areas. Starting back in about 1971, received dynamic range was drummed into my brain on nearly a daily basis until sometime in the 1990s when DoD, commercial shipping, etc., transitioned from LF-HF to satellite, cellular, etc.

To achieve the widest received dynamic range below about 30 MHz, we designed broadband receive antennas and RF distribution systems to allow setting the received external man-made, galactic, and atmospheric noise to be just above the noise figure of the receivers. In that way we had the widest dynamic range from a noise floor we had little control over, to the maximum signal levels that would cause issues within a receiver (intermods and various types of desensitizing).

In my nearly 60 years of playing in the LF thru HF spectrum, it really seems like RFI has been reduced. Much of my youth was spent living in my parent's corner grocery store. I hung around and eventually worked at the local radio-TV shop where I access to a great ham station. Our antennas were bombarded with noise from the 8-foot fluorescent light fixtures, the many neon signs, compressors, and other AC motors. Even the horizontal sweep oscillators of the old B&W TVs could really play havoc below 30 MHz.

For about the last 12 years I have lived with what is now a 500,000 volt power transmission line that runs the entire northwestern side of my farm. It was initially built in 1962 as a 350,000 volt line, which was both electrically and audibly very noisy. The line was rebuilt about 5 years ago. If I couldn't see it, I would hardly know it was there. My 135 foot doublet and my 65-foot end-fed inverted L are within 150 feet of it. Atmospheric noise is much stronger than the power line noise from about 300-400 kHz to around 8-10 MHz. Above that my noise level appears to mostly be set by galactic noise.

All of the utilities at our beach home are underground. When I clandestinely setup my end-fed half wave, I hear virtually no man-made noise.

I haven't heard ignition noise in years.

Does it mean anything? Maybe not, but in my mind it sure seems like man-made noise is a lot less pervasive than it was 20-30 years ago.

Ken
K8KJG

 

You could be right.

I only started listening in the late 80s. (Please don't ask why, that's a long story I've already told here.) At the time, I lived in the shadow of a TV tower, literally. I lived in a building sunk into a hill, and I was actually below grade, in the shadow of that TV transmit antenna. I could only watch channel 43, and it came in on every channel I tuned.

But the shortwave bands were different. I had a (still have it) 1947 Wards-Airline shortware receiver with a sort of pathetic two-turn wire loop, maybe totalling 28' in length. The bands were dead quiet where there weren't signals, and booming loud where there were.

In 2000, I quit listening, and started again in 2010. I live in a better location not that far away, and have a much better, outdoor, antenna. The noise is unbearable (and only increases if I switch back to that two-turn loop). A lot comes from SMPSs inside my house. But even with those unplugged, the racket from my not-that-close neighbors is very evident. Especially including the typical sound of a plasma TV.

 

They'll blame it on cellular. The ones with deep pockets.