- June 18, 2020 at 3:02 am #115203radio8zSenior Moderator
Total posts : 247
Some of you might recognize the lifted quote used in this thread title and may understand it better as you read on.
A few days ago my neighborhood lost power. The outage began at about 3:30 AM and lasted until 6 AM. I was viewing a streaming movie and had to shut down and to fend off boredom I turned on my battery powered portable AM radio. The most immediate effect noticed was that the signal received was free of the usual background noise. I tuned around to some familiar stations, some distant, and was reminded of how well the AM band used to perform, in the days of yesteryear, before all the noise producing devices in our homes have trashed AM reception. It used to be routine to listen to stations hundreds of miles away using only an AA5 receiver with a built in loop antenna but such is not possible today, at least here.
The FCC seems to be very concerned with broadcast interference potential from our Part 15 activities and thus restrict the power available to distribute our signals while either not able to address or not being concerned about broadcast interference caused by modern electronics in the home.
There is a 5 kW AM station transmitter located about 12 miles from me and I cannot receive it noise free on my portable radio. I cannot even receive my own Part 15 outdoor transmitter, which has a car radio range of 1.3 miles, in my home 40 feet away from the antenna.
I believe it is not possible to undo the light dimmers, switching power supplies, wall wart chargers, etc interference which has ruined AM reception inside dwellings leaving only mobile reception on AM using car radios distanced from the interference sources. As this relates to Part 15 AM, the only way to get a reasonable “audience” nearby would be to allow increased field strength (more power/longer antennas) which doesn’t seem to be in the works.
I conclude that Part 15 AM is useful only for broadcasting to ones self across the room and reaching out to a neighborhood audience given the noise levels in a typical dwelling is not realistic.
I would like to hear the experiences of others which might provide some encouragement regarding reaching an indoor neighborhood audience on AM despite the background noise level..
NeilJune 18, 2020 at 12:20 pm #115205MarkModerator
Total posts : 658
Well said, I am the same as you as I grew up with AM radio from the late 50s through the eighties.
It’s not just the local things in your house that are to blame but the power supply itself that’s dirty. That’s why there’s such a difference when using a portable on batteries or plugging it in.
Fortunately my AM station overpowers all this and is clean through out the house and outside. I don’t know the situation inside other houses but before I switched from FM to AM that was my big argument that you aren’t getting to many indoor places as the noise is a factor. You can go over a mile outside but do you get inside anywhere near that? But the AM advantages finally outweighed the disadvantages.
And I agree 100% the FCC should look at this interference and enforce their own rules about not causing interference. Wouldn’t this be the real AM revitalization instead of just cramming up the FM band with simulcasts of the AM stations? The real problem with AM is this + the lousey radios that give no priority to making decent AM receivers except a very few makes. Well, ebay is full of Sony’s and Panasonic’s etc from the 70s that are great. But as the saying goes they don’t make ’em like they used to.June 21, 2020 at 4:26 am #115218timinboveyParticipant
Total posts : 750
Although familiar with the concept this does not seem to be much of an issue for me. Granted I live in the boonies of northern Minnesota, where generally we enjoy a much lower noise floor on AM than in a major city, but few people have anywhere near the amount of potential interference causing doodads than we do. Yet I have very little additional (if any) noise on the AM band.
Just randomly off the top of my head this house has 5 computers running 24-7, 4 of which are in my studio where I not only run the Part 15 AM, but is also used daily for commercial production. They are all iMacs except for one Macbook Pro. Perhaps they create less noise than the typical PC product? Add to this all the usual computer peripherals like scanners, printers, cable modems, external drives, various burners, etc all of which have their own power supplies, etc along with 5 cordless phones and a million wifi gizmos. The studio is jammed full of equipment with various power supplies, from studio equipment such as mixers, processors, amplifiers, pre-amps, specialized audio equipment, modulation monitors, AM and FM receivers, scanner receivers, and heaven only knows what else. Yet I have no trouble hearing the 5,000 watt AM I work for that’s about 15 miles away, I can also readily hear the 10,000 watt AM that’s 40 miles away, and all sorts of DX stations that come rolling in at night. The whole house is full of mostly LED lightbulbs, and a few high watt equivalent CFL bulbs, not to mention many vintage fluorescent tube fixtures in the basement and garage. As a bit of an electronics geek the house is full of electronic things with power supplies, several iPads, iPhones, toys for my grandson like remote control cars and boats that all have chargers, etc. And all this stuff is in any state of use or recharging at any one time. In random tests I did a while back pulling the plug or shutting off most of this stuff has made no difference in AM reception on typical radios in the house. Maybe I’m just lucky, or maybe the low density of others in the area help in the overall tally of noise makers. We do live in a small town but are surrounded by other houses. But again, no big city noisemakers in town.
About the only issue I notice is a pretty substantial noise floor on the 20 meter ham band. But shutting off my “stuff” doesn’t seem to help this so I attribute that to general noise generated by the world clogging that up with noise. 40 and 80 meters are much better.
But really I experience minimal, in fact not even really observable noise from all our electronic stuff on the AM band.
- You must be logged in to reply to this topic.