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  #1  
Old 02-20-2020, 05:11 AM
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Jaypratt Jaypratt is offline
 
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Location: Hicks Airfield, Fort Worth,Texas
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Default Static

Any ideas on how to filter out static?
I installed a USB charging plug . The Scout ADSB, or I phone, when plugged in, creates static ,,, sounds like a hiss very loud. Similar to squelch on the com or intercom. But louder.
I get the same effect when I turn on a Trutrac Gemini too. This happens only on frequencies that I mostly use,,, 122.9 123.05
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  #2  
Old 02-20-2020, 07:13 AM
rocketman1988 rocketman1988 is offline
 
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Default Usb

This has been an ongoing issue with some USB ports. You might try getting one that has proven to be quiet and see if that fixes the issue. Steinair can help.
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  #3  
Old 02-20-2020, 10:22 AM
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Jaypratt Jaypratt is offline
 
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Default Static

The USB ports I installed cost $20. From Amazon look good, they have a Voltage led read out.
Sporty’s has USB charging ports for $350! That’s a little hard to take.
I’m thinking powering my $20 ones off a different battery. And ground.
Anyone tried that?
But the Gemini??? Why only on my most used com Chanel’s?
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  #4  
Old 02-20-2020, 10:41 AM
rocketman1988 rocketman1988 is offline
 
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Default Port

The ones I got from steinair were about $35 or so and they said they haven’t had any noise issues with them. They also said they have had to troubleshoot several other “noisy” brands...
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  #5  
Old 02-20-2020, 10:51 AM
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Look good and work good are two very different things!

Is this a built in USB power jack, or a cigarette lighter plug in?
If a built-in, most likely, the USB changer is emitting RF noise via the power leads (from the internal switching power supply)
An EMI troubleshooters best friends are a bag of ferrites and a roll of copper tape. For your issue, if you can source a ferrite ring, loop the USB adapter input power and ground wires through it a few times. If you don't have any ham friends, salvage one from inside an old PC power supply, monitor cable or similar. They are all over the place in computer components and cables. (that big lump in the cables. Just slice it out.) It is likely that this will fix the USB emissions issue.
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  #6  
Old 05-08-2020, 05:32 PM
64wing 64wing is offline
 
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Tell us about your audio infrastructure. Did you use shielded wire? (You'd be surprised what some folks use. Please don't take that as an accusation). The shielding should only be grounded at ONE end. Also ensure that grounding is adequate. Did you ground the USB port to the same ground as your audio? Does the static manifest itself in the cabin speaker if you have one? Both sets of jacks? Swap headsets? Try turning off one of your nav/coms and listening for the static when you plug something into the USB. Do you have an audio panel or did you go old school and just parallel to the jacks? Do you have an intercom? As I hope you have gathered by my Spanish Inquisition, there are many things to try when chasing static.
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  #7  
Old 05-08-2020, 06:14 PM
BillL BillL is offline
 
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Default

To fix the static from the USB adapter, get one without static. Jay it is a very common problem. Commit has a good report on USB chargers for apple products too.

Many of the chinese buck-boost inverters do this from poor design. Same issue with many LED lights, I have a couple of shop lights that kill radio reception in the hangar when plugged in. zzzzzzzzzzzzzzzt
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  #8  
Old 05-08-2020, 06:15 PM
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N941WR N941WR is offline
 
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Jay, this is the USB port I installed in my plane a few years back.

No noise of any kind. I wanted to have both a cigarette charger and a USB charger port.
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  #9  
Old 05-08-2020, 06:29 PM
Scott Hersha Scott Hersha is online now
 
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You could try a ferrite bead clamp installed over the USB cord near the source of power. Should absorb some of not all of the RF on that cable.
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  #10  
Old 05-09-2020, 07:49 AM
FinnFlyer FinnFlyer is offline
 
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Quote:
Originally Posted by Scott Hersha View Post
You could try a ferrite bead clamp installed over the USB cord near the source of power. Should absorb some of not all of the RF on that cable.
You mean "near the USB charger"?

If the USB charger is generating the noise, you'll want to kill it before it travels from the unit into the power cable that feeds it.

Oh, I see. USB cord from the port. Worth a try too.

You might also try to construct a small thin box around the unit. Cut and fold a thin alum sheet, for example. If you want to experiment -- otherwise spend the $35 and get a noise free one from Steins.

Finn
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Last edited by FinnFlyer : 05-09-2020 at 07:51 AM. Reason: Reread the post.
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