Switching Device Impact on BC Recepton

VicVic Solar Expert Posts: 3,113 ✭✭✭✭
Interesting article regarding impacts of switching devices on AM/FM/TV reception:

http://www.radioworld.com/article/johnston-laments-fm-noise/23733

FYI, Vic
Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 32,022 admin
    Re: Switching Device Impact on BC Recepton

    Yep--blame the flood of unregulated no-name imports. And US companies that do not care. A non-electronic failing product with response from US companies involved plus government CPSC (failing glass tabletops--poor heat treating/safety glass?):
    The Consumer Products Safety Commission investigated the issue in 2006 and asked Martha Stewart Living to re-design the table to make them less likely to shatter.

    We contacted a spokesperson for Martha Stewart Living Omnimedia and the company sent us a statement, which reads:

    "We take product safety very seriously. We provide the aesthetic design for beautiful products. Because we do not oversee the mechanical design, engineering or manufacturing of the products, we require all of our vendor partners to adopt and comply with product safety programs and reviews. If customers have any questions about these particular tables, they should contact Kmart customer relations at 866-562-7848."

    The spokesperson told FOX 31 Denver it is K-Mart’s responsibility to fix the problem.
    Stupid table has failed hundreds of times over 5+ years...

    Finger pointing 101. :grr

    -Bill

    I should add that the RF pollution problem has been around for years... When designing and "pre-testing" equipment we had to move a hundred yards or more from our office buildings to get the noise low enough to even see if we had RF issues to work on...

    In San Jose area--in the middle of a field--basically if we saw any noise from our units under test, we were failing (so much noise in the area--the noise floor in San Jose Valley was darn near failing when compared to an antenna just a few feet from the computer under test). For emissions, we where looking from 30 MHz to 1 GHz (or higher with new/faster processes).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • VicVic Solar Expert Posts: 3,113 ✭✭✭✭
    Re: Switching Device Impact on BC Recepton

    Well said, Bill.

    When doing Emission testing on our hardware, we used a site in Gilroy, with large plots of Ranch/Farm land surrounding, for its lower noise floor. IIRC, Apple uses a site near Bonny Doon (area) in an ocean-facing valley for similar reasons.

    The FCC has a mandated responsibility to protect Licensed entities from harmful interference, but it has been overpopulated with non-engineering types, often with external ties, which simply do not recognize interference, or are unwilling to do anything at all about it. (trying to be a bit circumspect).

    Oh well, Who Cares??!? Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • BB.BB. Super Moderators, Administrators Posts: 32,022 admin
    Re: Switching Device Impact on BC Recepton

    Sounds like we went to the same test site over the years (don't remember the company name). They had two or three places out there 10 and 30 meter. Also went to a site in Mariposa (Sierra foot hills too--CKC Engineering). And a few other places over my career.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Switching Device Impact on BC Recepton

    Bill;

    I know some places in Canada that are as free from RF noise as you can get on Earth. Perhaps you'd like to open a remote testing lab? And I do mean "remote"! Of course you will be bothered by FM interference - that's Frequent Moose, btw. :p

    Lillooet, BC would be a good testing ground for equipment vis temperature tolerance: +40C in Summer, -40C in Winter.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Switching Device Impact on BC Recepton

    marc,
    just because of your remote location does not mean it will be predominantly free of rfi. there may be just a bit less of it, that is true, but you'd be surprised how far that mishmash of hash travels. i'm thinking a metallic underground bunker would shield you for testing. some of the lower frequencies up to the am broadcast band may still show up underground too as it penetrates the earth easier and farther the lower the frequency is.

    it would be nice if the fcc started cracking down on this type of crap rather than collecting $ for selling frequencies they don't own to sell.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Switching Device Impact on BC Recepton

    Niel;

    I know RF is pretty hard to escape. It's pretty much everywhere on Earth to one degree or another. But we have some truly remote locations away from the utter chaos of civilization permeated with devices where only the boldest of signals reach. The cabin isn't one; we can look across the lake and see the communications towers on Mt. Timothy. No cell signal, though; only the wrong kind of RF. It's hard to pick up broadcast band radio there.

    As for the FCC doing what they should ... we should live so long. It is a government agency, after all. :roll:
  • BB.BB. Super Moderators, Administrators Posts: 32,022 admin
    Re: Switching Device Impact on BC Recepton

    Yea--those darn spark gap transmitter radio guys really ruined it for everyone. :p
    In 1905 a "state of the art" spark gap transmitter generated a signal having a wavelength between 250 meters (1.2 MHz) and 550 meters (545 kHz). 600 meters (500 kHz) became the International distress frequency. The receivers were simple unamplified Magnetic Detectors or electrolytic detectors. This later gave way to the famous and more sensitive galena crystal sets. Tuners were primitive or nonexistent. Early amateur radio operators built low power spark gap transmitters using the spark coil from Ford Model T automobiles. But a typical commercial station in 1916 might include a 1/2 kW transformer that supplied 14,000 volts, an eight section capacitor, and a rotary gap capable of handling a peak current of several hundred amperes.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Switching Device Impact on BC Recepton
    BB. wrote: »
    Yea--those darn spark gap transmitter radio guys really ruined it for everyone. :p



    -Bill
    I remember a story years ago about someone who was trapped in the wreckage after an automotive accident in a remote location. He used a pocketknife to scratch a series of lines through the paint on his metal dashboard (an indication of how long ago this was - all cars today have padded dashboards), pulled a nonfused hot wire out of the electrical system, and ran the wire over the scratches in an SOS pattern. A nearby ham radio operator picked it up as interference, recognized the Morse code, and used a direction finder antenna to find the wreck. Or at least that's how the story went. I read it in Reader's Digest, so it must be true. ;^)
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Switching Device Impact on BC Recepton

    might very well be a true story from 80 or 90 years ago, but in this day and age i wouldn't hold my breath on getting rescued from scratching sos with a wire. then again not that many people these days know how to send/receive morse code.
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