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-   -   Cell Phone Interference? (https://www.dvinfo.net/forum/wedding-event-videography-techniques/69396-cell-phone-interference.html)

Chad Martin June 12th, 2006 11:19 AM

Cell Phone Interference?
 
Has anyone experienced any issues with cell phone signals interfering with your camera's ability to process audio? I was at a wedding rehearsal this past Friday (using my FX1 and Rode Videomic) and while I was recording a few rehearsal shots I noticed a buzzing/beeping telegraph-type noise while listening in through my headphones. The interference lasted about 5-10 seconds, so I stopped recording and shut down the camera. I turned the camera back on and had no issues afterwards. My cell phone had been powered down because I have experienced a similar issue when recording at home with a handheld camera (while talking on a cell phone). The photographer did have a wireless transmitter for his flash, but it would seem strange to me that his system would've only caused the issue that one time.

I ended up making a sign to have all wedding guests power off their cell phones, but I doubt everyone noticed. Luckily, I had no issues at the wedding or reception.

I've had this same noise come thru my computer speakers at work (with my cell phone in my pocket, about 1 foot away from the speakers). Sometimes I get a call after hearing this interference noise, sometimes I don't.

Just curious if anyone has experienced this and if there are any ways to stop the interference.

Giroud Francois June 12th, 2006 11:23 AM

only one solution, cell phone jammer.

Barry Oppenheim June 12th, 2006 11:43 AM

Chad,

While I have never had cell phone interference/noise with a camcorder, I have had it with other audio equipment. This includes wired telephone handsets, audio mixer boards, wireless mic receiver bases, and mic preamps.

In all cases the interference occurs only when the cell phone is relatively close to the equipment (< 1 foot). In all cases the interference resolved when the cell phone was turned off.

The funny thing is that it does not happen all of the time. I have tried on several occasions to "purposely" induce the noise to try to figure out if a certain cell phone actions (receive, transmit, etc) induces the noise.

The only "sort of consistent" thing I have found is that if the cell phone is in an area with poor reception, the noise seems to be more likely. I am wondering if this may be due to the cell phone trying to increase output power in order to transmit or if the "locating network" function is at a different frequency or at a higher power than regular transmissions.

Barry

Glen Elliott June 12th, 2006 03:22 PM

I've never had cell phones interfere with audio on my cams. However on the Sony VX/PD's it's a known issue that cell phones will make the Optical Image Stabilization go bonkers. Suddenly you'll see the image start jerking even though there is no actual movement of the camera.

I found that this can only happen if the cell phone is in close proximity of the camera.

Jonathan Jones June 12th, 2006 11:18 PM

I have experienced this problem a couple of times in the past...once, when I first discovered this anomoly, I left my cell on in my vest pocket on a shoot and heard the sound in my earphones. Other times while shooting in crowds of people, it has cropped up as a cell user walks right by the camera.

I have also noted it once while running some video through my camera in my studio and left my cell on my desk right next to my setup...started getting the sound really clearly through my speakers.

I really get paranoid now while on a shoot, trying to make sure that I am not around cell user, and trying to keep my headphones on all the time, to monitor where I stand and if a cell user gets to close, I can respond accordingly.

I am not familiar with the earlier mentioned cell phone jammers. I am certainly curious as to what they are and how they work....I guess I will do a little googling this evening on it.
-Jon

Giroud Francois June 13th, 2006 01:06 AM

phone jammer are usually just small boxes (like a pack of cigarette) with several short antennas (2 or 3).
you power it up and immediately , all phones in a range about 10 feet or more cease to work (they are not looking for network, so the noise is stopped).
they usually are expensive (over 200$), but you can mount one on your cam and be quiet everywhere you shoot (People will think you are using a wireless mic.)
i got a pocket model i can clip on a belt that looks like a cell phone (with dual antenna).
this shop has all of them
http://www.globalgadgetuk.com/Personal.htm

Chad Martin June 13th, 2006 11:15 AM

Thanks for all of the replies. I'll have to consider powering off my cell phone and keeping it in the camera case to minimize the possibility of interference. Or, I'll just have to leave the phone in my car.

Christopher Thomas June 13th, 2006 11:28 AM

Chad,

I have the identical setup, and I've experienced the same problem with my cell phone. (Luckily I was doing test shots in my den when I discovered this!) My phone will occasionally search for a network to get a time update or something. I've gotten in the habit of just leaving it in the camera bag on silent.

So far no problems during a ceremony, but I mainly use the iRiver audio for that anyway, mixing it with the Rode audio for ambient noise. I do ask the groom to turn his cell phone off if he's carrying it, as I don't know if that will interfere with the iRiver.

HTH!
Chris

Ben Brainerd June 13th, 2006 03:20 PM

I've had a similar problem in the past, and I ran it past a couple of friends (An audio engineer and an electronics whiz).

The answer is pretty much what Barry said. Every so often, a cell phone will send out a signal to the network. Basically an "I'm here, in case any calls come in" type of thing.

And it will affect pretty much everything. It's VERY noticable on pro-grade monitor speakers, which tend to be less shielded against outside interference. It also affects microphones, and, if you're exceptionally unlucky, things like OIS.

It shouldn't affect an iRiver, but it COULD affect the mic. Your milage may vary. I usually ask the groom and everyone else in the wedding party to leave their phones elsewhere, or at the very least turn them off. Can't do much about the rest of the audience, but the phenomena does tend to be very limited in range.

And in case you're looking into a Jammer, consider this: If you're in the US, and you get caught using one, you're looking at an $11,000 fine, and up to a year in prison. One could say that they're just a wee bit illegal.

Steven Davis June 14th, 2006 07:48 AM

Call me crazy........
 
Ok, but when I first used my Senn G2, I had a like a couple of people power up thier cells and start taking pictures during teh ceremony. I watched a couple of them closely and it appeared that thier usage of the phone caused some drop outs. I know I may be crazy, but they were within 15 feet or so of me (small room) and it appeared to be the case.

I know I'm crazy.

Dale Mellinger June 14th, 2006 03:28 PM

Steven,

I don't think you're crazy. I believe it has to do with a number of factors. My Nextel seems to be a particulary bad offender.

I've noticed cell phone interference on my car radio, my computer speakers, my audio equipment and other stuff. Sometimes a phone can be a good 6 - 8 feet away and I still have problems.

During the few live performances I've been at, someone makes an anouncement that all cell phones are to be turned completely off. Depending on how much co-operation you have, perhaps a notice could be printed in the "program". Also, signs outside the auditorium/sanctuary might help as well.


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