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  #1  
Old 01-31-2014, 02:09 PM
sapincher sapincher is offline
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Default 96.1Mhz super-interference on clip+

I was wondering if anyone else had this same problem. On my clip+, when listening to the radio I came across a station that is almost completely silent except for a soft ticking noise - 96.1Mhz. This station picks up interference from the display when it's on (each tick is a display refresh) and the flash memory access noise is incredibly loud on it. Listening to it is sort of like listening to just the electronics inside the player.

You can here some of this interference just a little bit on 95.9 and 96.0Mhz, but it's completely absent on all other frequencies.

Because of how clear it is (it has the highest signal strength of any station), it seems like the player is hard-wired to do this. I found just a few other people complaining about this problem on Google over the last few years, but it's been surprisingly quiet.

Does your player do this?

Edit: I forgot to mention that it happens with Rockbox and original firmware on mine.

Last edited by sapincher; 01-31-2014 at 02:15 PM.
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  #2  
Old 01-31-2014, 02:29 PM
saratoga saratoga is offline
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24MHz is the pclk IIRC, and 96 is exactly 24x4. My guess is theres some wiring defect on your device's radio and you're catching the 4th harmonic of the clock.
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  #3  
Old 01-31-2014, 02:42 PM
sapincher sapincher is offline
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Ah, that's certainly a good explanation. Does anyone else have this problem or is it just my device?
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  #4  
Old 01-31-2014, 07:33 PM
MattMc3 MattMc3 is offline
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There is a local radio station in my area on 96.1 and what I hear on that frequency is just the radio broadcast - no internal electronic noises. On my Clip+ I can only tune to the surrounding frequencies of 95.9 and 96.3 (not 96.0 or 96.2), and all I hear on them is just the normal static of 'no reception'. If it matters (due to different radio tuning requirements?), mine is a US model being used in the US. Hope this helps.

Matt
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  #5  
Old 01-31-2014, 08:36 PM
Sleep mode zZ Sleep mode zZ is offline
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My Clip Zip definitely can pick up some electrical noise in that frequency. It is silent otherwise but near different devices like my computer or a display there is some noise. Strongest sound come from from my router. There is also some noise when I put my hand on the display of the Zip, and the noise gets significantly louder when the display is on. Interesting.
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  #6  
Old 01-31-2014, 09:46 PM
sapincher sapincher is offline
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Quote:
Originally Posted by MattMc3 View Post
mine is a US model being used in the US.
Same for me too, I am in NM. There's actually a radio station on 96.1 near me too, but the interference is too strong to pick it up.

Quote:
Originally Posted by Sleep mode zZ View Post
It is silent otherwise
When you say silent, do you mean that ~96Mhz is devoid of normal radio static - it is completely quiet except for interference? That's what I'm experiencing.
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  #7  
Old 02-01-2014, 07:56 AM
MattMc3 MattMc3 is offline
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This morning I went through my entire FM band and I didn't hear any internal-type noises on any frequencies. All I heard was a strong FM signals on local stations, weak FM receptions on distant stations, and static on unused frequencies. On 103.7 I did have complete silence - no static, reception, or electrical noises, but there is a strong broadcast signal on 103.9 in my area so it might be related to that. I listened to 96.1 for a while and I didn't hear any unusual noises (other than Ke$ha) during quiet parts of music or in between songs either.

My firmware version is V01.02.15A and my Clip+ is probably about three years old.

Try recording an MP3 using the built-in FM recorder and see if it records the electrical noises. If you have a way to upload the MP3 clip, I'd be interested to hear it.

I found a thread on the SanDisk forums that mentioned 95.9 and 96.1 not working properly. The poster said that setting the Clip+'s radio mode to "World" (instead of "USA") allows you to tune in smaller increments. He was able to listen to 96.1 by tuning to 96.15. He didn't mention any internal noises though, so that might not be the same issue. Go to SETTINGS > RADIO OPTIONS > FM REGION to try it out. I didn't hear anything unusual in world mode either.

Matt
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  #8  
Old 02-01-2014, 11:17 AM
Sleep mode zZ Sleep mode zZ is offline
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Quote:
Originally Posted by sapincher View Post
When you say silent, do you mean that ~96Mhz is devoid of normal radio static - it is completely quiet except for interference?
Yes.
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  #9  
Old 02-01-2014, 01:47 PM
sapincher sapincher is offline
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The interference is picked up in the attached recording, but it's quieter in the recording than it is when just listening. When clicking around while listening to the station, each click makes a very audible iPod clickwheel clicking sound, whereas it's barely audible in this recording.

The first minute of the recording is the sound of flash memory access when updating the DB, then it suddenly stops at 1:06 and from there you can almost hear the clickwheel noises but they are really quiet.

Quote:
Originally Posted by MattMc3 View Post
He was able to listen to 96.1 by tuning to 96.15.
I tried this but the interference was really strong - it jams a station on 96.3 too.
Attached Files
File Type: zip R_FM_140201-123805.zip (2.42 MB, 3 views)

Last edited by sapincher; 02-01-2014 at 01:52 PM.
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  #10  
Old 02-02-2014, 07:49 AM
MattMc3 MattMc3 is offline
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After listening to your uploaded MP3, I agree with you that the noises sound internal to the player. All I can suggest now it to try and eliminate everything in your control that could possibly affect a barebones Clip. I doubt any of the below suggestions will help but it's worth a shot (and free).

You said that you've changed firmware, so that's not it. Since the Clip uses the headphone cable as an FM antenna, try using a different length cable - It might have an effect on FM reception. Try using different headphones - Maybe the headphones ones you are using are somehow causing internal interference. Try removing the headphones altogether and connect the headphone-out to a stereo system with a line-input. Try connecting a 3.5mm cable to the headphone jack (with the other end not connected to anything) to use as an antenna and then make another MP3 recording. Listen to it and see if it's the noises are the same without any headphones or external equipment connected. Try removing the MicroSD card if you are using one and power on the Clip with just the internal memory.

That's all I can think of trying right now. You might just have a defective Clip+. Good luck.

Matt
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  #11  
Old 02-07-2014, 01:31 AM
sapincher sapincher is offline
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I get the interference in all of those situations - except oddly when a USB charging cable is plugged in - then I get zero reception on any stations. Go figure... I guess I'll just live with this problem. However, I can imagine other people with this problem who listen to FM radio more would be a lil more irked.
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