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  1. #1

    Strange interference on wifi SB2s

    Hi All

    Can anyone shed any light on a strange intermittant problem I'm having?

    I have 2 SB2s & 1 SB3 in the house. The SB2s are on wifi, the SB3 is on wired Ethernet. Occasionally - this is usually in the evenings I'm getting very bad static on the SB2s - a sort of fizzing & popping noise at a constant volume. Comes through my amps whether the SB 2s are on or off, or even a different source selected. It goes away when they are powered down. The SB3 does not seem to be affected which may be because its on wired Ethernet, or not suceptable to the problem.

    Any ideas? I think it may either radio bourne noise thats getting through somehow - though I don't have a taxi control next door or anything I can think of. Or it could be some form of mains RF noise which combined with the presence of the wifi module causes the issue?

    When it stops, it stops suddenly & goes right back to normal on both players at the same time.

    The SB3 has no wifi card.

    Cheers

    MBM

  2. #2
    Senior Member toby10's Avatar
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    Quote Originally Posted by mustbemad View Post
    Hi All

    Can anyone shed any light on a strange intermittant problem I'm having?

    I have 2 SB2s & 1 SB3 in the house. The SB2s are on wifi, the SB3 is on wired Ethernet. Occasionally - this is usually in the evenings I'm getting very bad static on the SB2s - a sort of fizzing & popping noise at a constant volume. Comes through my amps whether the SB 2s are on or off, or even a different source selected. It goes away when they are powered down. The SB3 does not seem to be affected which may be because its on wired Ethernet, or not suceptable to the problem.

    Any ideas? I think it may either radio bourne noise thats getting through somehow - though I don't have a taxi control next door or anything I can think of. Or it could be some form of mains RF noise which combined with the presence of the wifi module causes the issue?

    When it stops, it stops suddenly & goes right back to normal on both players at the same time.

    The SB3 has no wifi card.

    Cheers

    MBM
    As a starting point for WiFi interference trouble shooting, do a quick survey of your WiFi networks around you where your (whichever) computer program shows you ALL available WiFi networks.

    You may find in the evenings your neighbor is turning on his WiFi and is using the same WiFi channel as you are using. Channels are 1 through 11. Change the channel on your router to a channel not being used near you.

    If it's a non-WiFi signal conflict (HAM radio operator, etc...) you may need to just try all channels till you find one that fixes the interference.

  3. #3
    Senior Member
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    Quote Originally Posted by toby10 View Post
    Channels are 1 through 11.
    I through 11 in the USA, 1 through 13 in Europe. Otherwise I agree with your post.

  4. #4
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    Wifi doesn't work that way. You would not get static or popping. It would just stop playing if the wifi were the problem. It sounds like some _other_ kind of inducted noise in the analog side of your setup.

  5. #5
    Senior Member tedfroop's Avatar
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    noise

    Like my Blackberry induces if its too close to the amp...
    "Good judgement is the result of experience ... Experience is the result of bad judgement."

  6. #6
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    Switching regulators

    I have this problem with an SB1 that generates radio interference whenever it is plugged in.

    The switching power supplies that convert the 120VAC power line voltage to various DC voltages used by the SB1 electronics are the culprits. The very fast switching transients in these power supplies have very broad spectral content, extending into the radio frequency spectrum. Because the Squeezeboxes have power cords that plug into the house wiring, this high frequency noise gets on the house power lines and from there into anything else that is plugged in - audio amplifiers, AM radios, TVs, cable boxes, etc. If these latter do not have adequate power line filtering, the noise from the power lines can modulate signals inside these electronic devices, resulting in noisy output. This is how most noise from the SB1 power supply gets into an audio amplifier - the audio lead connections are generally not the culprits. It is possible to build switching power supplies and power line filters such that this type of parasitic noise is eliminated or reduced to the point that it is not noticeable, but this type of design was not done for the DC supplies in the SB1.

    In the case of the SB1, there is a switching supply right in the AC power plug. This supply generates 5VDC that travels down the SB1 power cord to the SB1 enclosure, which has more switching supplies inside that generate other DC voltages. This "plug supply" is particularly noisy and puts a lot of noise on the power line. I cured this problem by getting an old "linear" 5VDC supply from a discarded stand-alone computer disk drive and wiring it in to replace the unit in the SB1's power plug. This older power supply has an iron power transformer, uses passive diode switching at power line (low) frequency, and incorporates smoothing filters, so it generates no perceptible interference in my audio amp or radios. It is also bulky, heavy, more expensive to manufacture, and somewhat less efficient than the high frequency switching supply - these latter are the reasons the switching supplies were used in the first place.

    I opted for the less efficient DC power supply and eliminating the noise in my audio amp and AM radio.

  7. #7
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    Quote Originally Posted by rkerr View Post
    I have this problem with an SB1 that generates radio interference whenever it is plugged in.
    ...
    I opted for the less efficient DC power supply and eliminating the noise in my audio amp and AM radio.
    Yea, a bad or noisy switching supply can be a huge pain with poorly isolated equipment. Thankfully there are quality switching supplies out there that don't have these kinds of issues. AFAIK Slimdevices supplies much better quality switching supplies these days.

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