RF interference from USB power ports

[sscheuer47]

I have added two USB power ports to supply power to two cameras and they are getting power from battery through a FZ-1. The USB's are causing RF interference.
It was suggested to me that I put a 25 ohm 5 watt resistor on the positive side. Local Radio Shack is going out of business and does not stock. Anyone know where to get this resistor?

 

[stevedfive]

You should try a RF Ferrite Snap Choke.

 

[ThreeWheels]

You should try a RF Ferrite Snap Choke.

I have no idea what he's talking about, but I'd bet real money he's right.

 

[Highwayman2013]

You should try a RF Ferrite Snap Choke.

Sounds like a left handed smoke shifter.

 

[stevedfive]

Two for $5.99. The magnets eliminate the excessive static that cause the RF interference noise.

 

[Oldfox]

Rf choke

They look like one of these available on Amazon:

http://www.amazon.com/Movable-Inner...=UTF8&qid=1428462831&sr=1-1&keywords=rf+choke

Hope you can follow the link.

Order one for each cable to fit the diameter of the cable.

 

[markyodo]

Parts Express

Parts Express has been my go to store for audio / video / cabling for years.
Here is your part.
http://www.parts-express.com/25-ohm-5w-resistor-wire-wound-5-tolerance--015-25

 

[finless]

Mouser electronics

www.mouser.com

Now I will add. You don't really say what is getting interference? The cameras?
If so and the 12V run is long (like from front of the Spyder to the back), then chokes or a resistor may not help. You might have to use shielded cable and ground the shielding at both ends as the wire is acting like an antenna.

Bob

 

[Highwayman2013]

Two for $5.99. The magnets eliminate the excessive static that cause the RF interference noise.

Is that what those things are on some cables. Always learning.

 

[Cyclist922]

Is that what those things are on some cables. Always learning.

Yep. Ferrite inductors have been a standard way of shielding for years.

 

[bluestratos]

What system is being affeted by the RF noise?

 

[sscheuer47]

Thanks for the replies. It is nice knowing there are some electrical savy spyderriders around.

I get the radio static whenever I plug into the rear usb power plug to get power to the rear camera. The usb plug has several feet of +wire and -wire. The Garmin Virb camera works fine.

Should I use both the magnets and the resistor?

 

[ursamajor35126]

It may be the quality of the USB cables you are using. I'd try another mfg of cable if you're getting interference from the factory jacks. :hun:

 

[IdahoMtnSpyder]

Thanks for the replies. It is nice knowing there are some electrical savy spyderriders around.

I get the radio static whenever I plug into the rear usb power plug to get power to the rear camera. The usb plug has several feet of +wire and -wire. The Garmin Virb camera works fine.

Should I use both the magnets and the resistor?

Are you plugging a USB power adapter into the 12 volt outlet in the trunk? If not, what are the + and - wires connected to? USB adapters emit RF noise if they are not made properly. Your best bet may be to try different USB adapters until you find one that doesn't emit so much RF noise. Also, keep the USB adapters and cables away from the antenna as far as possible. I ran into that problem when I was conjuring up a USB power supply for my tablet GPS. The first one connected directly to the power leads coming from the radio. That fed RF noise right into the radio. I ended up with a USB adapter in the area just above the coolant bottle and run the USB cable to the dash.

 

[sscheuer47]

To be clear, the magnets are attached to the radio antenna wire? Is that correct? Perhaps adding to the USB cable also will help?

I am using a 'Panel Tapp' Usb power port located below the left passenger hand rail. The power and ground wires run to a FZ1 located front left of bike. The Usb cable runs along the rear seatback up to the camera located on top of the truck lid.

I replaced the OEM antenna with a hidden antenna located inside the rear panel just below the rear truck handle opener.

Good reception on radio until camera USB cable is plugged in providing power to the camera, then some static with lower volume. No problrms with camera.

 

[sscheuer47]

Thanks to all who have responded.

Some quick research on 'RF Ferrite Snap Choke' shows that not only the size of the hole for the cable but also there are three types.

Have seen these on computer type cables.

Question: Would the same type be used for the power cable, USB cable as well as the radio antenna cable on the RT?

 

[sscheuer47]

UPDATE

Chokes and resistors ordered from above recommended sites. Also ordered a PDM60. All work will have to wait until after we get back from Spyderfest.

 

[Phil]

A lot of the USB and other power supplies use what is called a 'chopper' circuit to take the 12vdc down to 5vdc. They call it a chopper because it chops out parts of the 12vdc, and reassembles it to make the 5vdc (trust me). They work well, but some can put our RF interference like you are seeing. The resister simply adds 'load' to the circuit thus dampening the chop. Somewhat.

The 'magnets' you are talking about are not really magnets. They are ferrite cores (aka chokes). They come in snap on versions and doughnut type. If you are trying to suppress RF noise, you would put these on anything EXCEPT the antenna! The antenna WANTS to receive RF. You can put them on the USB cable, on 12vdc wires, etc. The ferrite cores act like high frequency absorbers.

There's another old trick we used in broadcast and that was to tie knots in wires when we couldn't get our hands on the ferrite cores right away.

 

[eddieshep999]

I am getting Radio interference on My Spyder Radio when I apply apply the brake otherwise it's fine
I have the HMT brake light fitted and the front fender LED's which are both running lights and function as an extra brake lights
what do I need to do/fit to stop this happenig

 

[finless]

When you say radio interference, do you mean it is interfering with radio station reception? Or some form of noise coming out of the speakers?

Bob