RadoStefanov Posted February 3, 2016 Report Share Posted February 3, 2016 Lately I have noticed all kinds of different fans spew a lot of RF pollution. From computer fans to ceramic heaters fans. There is extreme amount of interference. The interference starts from 470mHz all the way to 2.4Ghz. Are fans not tested by anybody before import? ______________________________________________________ Fan On Fan Off Quote Link to comment Share on other sites More sharing options...
Moesound Posted February 3, 2016 Report Share Posted February 3, 2016 Interesting that you bring this up, Rado. All last week I noticed strong activity across my radio spectrum whenever I was set up near VTR and DIT (especially bad when sandwiched in between). They were not transmitting anything, so it made no sense to me. However, by moving as little as 10 feet away, all was clear. Same thing today, where we are deep into Newhall Ranch, where my radios showed all clear upon setup this morning. As soon as I moved my cart by VTR/DIT, crazy RF across the board. Both these technicians carts have multiple fans within. Moved away, all clear. Lesson? Stay away from DIT/VTR.... Thanks for posting. Moe Quote Link to comment Share on other sites More sharing options...
afewmoreyears Posted February 4, 2016 Report Share Posted February 4, 2016 We were on a set, Ext. LA area, was getting HORRIBLE RF interference across like 5 blocks... Could not eliminate the problem... Worked through it that day and was mystified... Tried eliminating , moving, changing gear out... Nothing... Week later, another location in LA, Exterior again, same VTR guy, spray started around 10am... ( later we figured thats when the VTR guy got hot!!) Same thing, could not figure it out... Again tried all the usual stuff.... I then looked over at my VTR buddy and said, hey, turn off your 6" fan... (he used it to blow on him)... AND AWAY IT WENT.... on and off a few times and that was it... Of all the crap on a film set, his little cooling fan made me miserable a few shows in a row.... I was very very happy to find it... I then spoke to a friend who mixed with the same VTR guy and asked about it... He said it killed him for almost a week!!! Quote Link to comment Share on other sites More sharing options...
old school Posted February 4, 2016 Report Share Posted February 4, 2016 The curse of the Video Monkey. Who knew? Good info to have. Thanks. CrewC Quote Link to comment Share on other sites More sharing options...
atheisticmystic Posted February 26, 2016 Report Share Posted February 26, 2016 How does a spinning propeller generate radio waves ? Quote Link to comment Share on other sites More sharing options...
RadoStefanov Posted February 26, 2016 Author Report Share Posted February 26, 2016 added pictures in the first post Quote Link to comment Share on other sites More sharing options...
Matt Mayer Posted February 26, 2016 Report Share Posted February 26, 2016 22 minutes ago, atheisticmystic said: How does a spinning propeller generate radio waves ? It ain't the propeller, it's the magnets driving the propeller. Quote Link to comment Share on other sites More sharing options...
Philip Perkins Posted February 26, 2016 Report Share Posted February 26, 2016 Electric motors= RF cloud. Years ago I worked with a VTR guy who not only had a couple of fans, he had a big invertor working (with its own fan, of course). When the Villagers would gather around him their Comteks would go mega-hash. When they backed away, all good. We ran around finding him AC everywhere we went after that…. Quote Link to comment Share on other sites More sharing options...
Ken Wilkinson Posted February 26, 2016 Report Share Posted February 26, 2016 Good to know, thanks. Quote Link to comment Share on other sites More sharing options...
atheisticmystic Posted February 27, 2016 Report Share Posted February 27, 2016 On February 26, 2016 at 8:19 AM, Matt Mayer said: It ain't the propeller, it's the magnets driving the propeller. Thanks, Matt. Just chuck that lil' shred of newb off to the side, I wont be needing it anymore...lol. best, steven Quote Link to comment Share on other sites More sharing options...
Wandering Ear Posted February 29, 2016 Report Share Posted February 29, 2016 Most of the vtr carts I've worked with have at least one or two fans running on them, and they always have a lot of rf around their cart. I've never asked to switch off the fans to see how much of it is from that vs the other things, but it's common enough for me that I usually hard wire or run stronger wireless to feed vtr. Quote Link to comment Share on other sites More sharing options...
Nicko Posted April 3, 2016 Report Share Posted April 3, 2016 I've noticed a similar effect coming from cheap, poorly insulated SDI cables on cameras. Quote Link to comment Share on other sites More sharing options...
Gordonmoore1 Posted April 8, 2016 Report Share Posted April 8, 2016 Many DC motors are speed controlled by a PWM - pulse width modulated - controller. These controllers, unlike a Rheostat control (which changes voltage through variable resistance), delivery the full DC voltage but do so with pulses at full voltage. So, instead of knocking down the voltage to slow the motor, they reduce the amount of time the motor gets to see power by switching it on and off at a very fast pace. Unlike a resistor, there is no wasted voltage being blown off as heat by the resistor so they are more efficient. Unfortunately, these things switch on and off very rapidly and the controller must have a clock or oscillator - all of which can generate RF. These magnets aren't the problem, generally - it's probably the PWM controller. They aren't tested as RF devices so they get passed more easily. Quote Link to comment Share on other sites More sharing options...
Izen Ears Posted April 12, 2016 Report Share Posted April 12, 2016 Wow! Thanks for this. Wow again. Dan Izen Quote Link to comment Share on other sites More sharing options...
RadoStefanov Posted April 12, 2016 Author Report Share Posted April 12, 2016 thanks Gordon. Quote Link to comment Share on other sites More sharing options...
LarryF Posted April 12, 2016 Report Share Posted April 12, 2016 Re: Gordon and fans. This is what you get from Gordon after he's bought fans for his homemade hot air solar heating panel. If you have a spare hour or so, ask him about rear main seals on a MG-TD. Best Regards, LarryF Quote Link to comment Share on other sites More sharing options...
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