Hugh Holesome Posted June 7, 2010 Report Share Posted June 7, 2010 I have a KTek aluminum shorty pole, 9ft for ENG use. Lately bringing it out for second stick I have noticed this stick picking up broadcast radio! WTF! Identical mics, swapped cables etc and the determined culprit was the stick. This is internally cabled so my first guess is something went amiss internally. That said, I went externally wired wrapped on the same pole and still got interference. Plugging the mic in and hanging it on a C stand does NOT reproduce the sound... Detroit is RF hell and I know this, but today's location in the 'burbs was also picking it up. Is this common or is there a fix for this? Thanks in advance Hugh Quote Link to comment Share on other sites More sharing options...
Derek H Posted June 7, 2010 Report Share Posted June 7, 2010 Can you actually here the radiostations or is it just buzzes and hums? I had a boompole act like this once when I was in line of sight to the Hancock tower in Chicago.. Never fully troubleshooted the problem though.. could have been another cable or the PSC alphamix. I would check all your cables, including the coily in the pole with a tester of some sort. I would probably pull apart the connectors and look for a short or incorrect wiring as well. good luck! -d Quote Link to comment Share on other sites More sharing options...
Hugh Holesome Posted June 8, 2010 Author Report Share Posted June 8, 2010 I could be hosting sing-alongs! Yes it is actual stations bleeding. I guess I will begin with a full disassemble and check for grounding issues. Quote Link to comment Share on other sites More sharing options...
bigmaho Posted June 8, 2010 Report Share Posted June 8, 2010 What mic and mixer/recorder are you using? Does it happen with different microphones? You can try the Neutrix rfi suppression xlr connectors on the female end. Bily Sarokin Quote Link to comment Share on other sites More sharing options...
berniebeaudry Posted June 8, 2010 Report Share Posted June 8, 2010 I had this happen with the exact same pole. The rf was loud enough to tell which AM station it was. I was using a short jumper from my mixer to a phantom power supply and part of the issue was there. The rf didn't totally go away till I switched out my mic. Went from a Gefell M-210 hyper to a Schoeps CMIT 5U. Maybe the pole itself is acting as giant antennae for some reason. Bernie Quote Link to comment Share on other sites More sharing options...
bigmaho Posted June 10, 2010 Report Share Posted June 10, 2010 My guess is that it is an AM radio station. And yes, the metal pole and mic cable are making a perfect antenna and tuning coil for a long wave rf signal (870 kHz compared to 88 mHz). Also, MANY mics have severe rf sensitivity to AM signals making them little detectors. All you need to make an AM radio is an antenna (your boom and cable), a detector (a 10 cent geranium diode or a $2000 mic) and a ground (your mixer or recorder). One simple solution (short of changing the mic or pole) is to wire the shield to the case of the female xlr connector. Two Tiny capacitors, .01uf, wired from pin two to the ground lug and pin one to the ground lug should also go a long way towards preventing rfi. Keep the capacitor leads as short as possible. Billy Quote Link to comment Share on other sites More sharing options...
Marc Wielage Posted June 10, 2010 Report Share Posted June 10, 2010 If Hugh has this as an option, my suggestion would be to try a carbon-fiber pole and see if that eliminates the problem. I know it's more expensive, but the boom ops really appreciate the lighter weight. --Marc W. Quote Link to comment Share on other sites More sharing options...
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