Bike Forums

Bike Forums (https://www.bikeforums.net/forum.php)
-   Electric Bikes (https://www.bikeforums.net/electric-bikes/)
-   -   AM Radio Interference (https://www.bikeforums.net/electric-bikes/1226462-am-radio-interference.html)

Lambkin55 03-22-21 09:21 AM
AM Radio Interference
 
I like to ride and listen to the radio. (Yeah Yeah I know... But I do it and have done so, safely, for 35 years!) Electric Bikes give off an interfering signal as they run. When I ride an e-bike my AM radio has static. Does any body have a cure for this problem?

BTW: Listen to FM is an unacceptable answer!

Pop N Wood 03-22-21 11:14 AM
Wrap your controller in aluminum foil.

Ideally the device should be shielded and filtered so it doesn't radiate radio energy. The FCC has rules governing these things, but some devices are more compliant than others.

If you can find the source of the static than you might be able to install some RF filters on select lines to reduce the interference. Car ignitions often had "condensers" hooked to the distributor to do this, could be something that simple. But it would be a bit of a science experiment, best bet is to to find some local electronic geek to solve.

Another option might be getting some separation between the AM antenna and the bike electronics. Only so far you can go with that.

Beyond that make sure all of your electrical connections are clean and tight. A dirty connection can cause noise.

BTW I used to listen to football games on AM radio when I rode. Nothing wrong with that.

Calsun 03-25-21 03:31 PM
If you have earbuds their cords are acting as an antenna which is why the interference. A FM radio may be less of a problem or use a smartphone with one of the radio apps (which is why I do as the local radio stations leave a lot to be desired.

Leisesturm 03-30-21 02:06 PM
Originally Posted by Lambkin55 (Post 21978991)
I like to ride and listen to the radio. (Yeah Yeah I know... But I do it and have done so, safely, for 35 years!) Electric Bikes give off an interfering signal as they run. When I ride an e-bike my AM radio has static. Does any body have a cure for this problem?

BTW: Listen to FM is an unacceptable answer!
What if that is, in fact, THE answer? AM radio is for utility, sports, and talk radio and everyone knows it has awful resistance to noise. It isn't our job to get you out of the corner you have painted yourself into but you have gotten excellent ideas from others.

klevin 03-30-21 05:34 PM
Originally Posted by Pop N Wood (Post 21979218)
Wrap your controller in aluminum foil.

Ideally the device should be shielded and filtered so it doesn't radiate radio energy. The FCC has rules governing these things, but some devices are more compliant than others.

If you can find the source of the static than you might be able to install some RF filters on select lines to reduce the interference. Car ignitions often had "condensers" hooked to the distributor to do this, could be something that simple. But it would be a bit of a science experiment, best bet is to to find some local electronic geek to solve.

Another option might be getting some separation between the AM antenna and the bike electronics. Only so far you can go with that.

Beyond that make sure all of your electrical connections are clean and tight. A dirty connection can cause noise.

BTW I used to listen to football games on AM radio when I rode. Nothing wrong with that.
The condensers that were part of distributors were to minimize arcing of the points, not for RF interference. OTOH, many cars had special spark plug wires with resistance built in to minimize interference.

No one asked what kind of motor? If it's one with brushes, that's probably the problem. Those are rare though. Most are brushless. But you are right about connections. I'd start by looking at ground connections, and making sure the builder isn't just using the frame for ground (unlikely, but who knows?). Use a separate ground wire.

You might also "wave" your radio over various parts of the bike (if you can do it while stopped?) to see if the static is worse at some point. Finally, is it everywhere on the AM band? If so, sparking is your most likely cause.

Pop N Wood 03-31-21 07:19 AM
Originally Posted by klevin (Post 21992540)
The condensers that were part of distributors were to minimize arcing of the points, not for RF interference. OTOH, many cars had special spark plug wires with resistance built in to minimize interference.
Condensors inside the distributors store up a charge to fire the plugs when the points open.

My 1965 Oldsmobile Jetstar 88 with the 330 cubic inch V8 (I miss that car) had a second condensor on the outside of the distributor to shunt high frequency noise to ground. A filter capacitor.

WWII German fighter ace Gunther Rall said his first impressions when flying the early jets was the quality of the radios. Apparently the ignitions on the piston engines seriously interfered with the radios.

klevin 03-31-21 10:00 AM
Originally Posted by Pop N Wood (Post 21993310)
Condensors inside the distributors store up a charge to fire the plugs when the points open.

My 1965 Oldsmobile Jetstar 88 with the 330 cubic inch V8 (I miss that car) had a second condensor on the outside of the distributor to shunt high frequency noise to ground. A filter capacitor.

WWII German fighter ace Gunther Rall said his first impressions when flying the early jets was the quality of the radios. Apparently the ignitions on the piston engines seriously interfered with the radios.
Better answer but still not quite right. The energy for making the spark was (and still may be) stored in the magnetic field of the ignition coil - one reason they were so big. But yes, ignition noise was and can still be a problem.

Pop N Wood 03-31-21 10:15 AM
Originally Posted by klevin (Post 21993653)
Better answer but still not quite right. The energy for making the spark was (and still may be) stored in the magnetic field of the ignition coil - one reason they were so big. But yes, ignition noise was and can still be a problem.
Shoot, that is right. Current flows through the coil when the points are closed creating a magnetic field. When the points open the field current collapses as it is shunted through the condenser to ground. That changing field causes the spark to fire. Arcing of the points really has nothing to do with the condenser.

klevin 03-31-21 11:00 AM
Originally Posted by Pop N Wood (Post 21993693)
Shoot, that is right. Current flows through the coil when the points are closed creating a magnetic field. When the points open the field current collapses as it is shunted through the condenser to ground. That changing field causes the spark to fire. Arcing of the points really has nothing to do with the condenser.
You're getting closer! But the whole purpose of the capacitor, what we used to call a condensor, is to suppress point arcing. If you've ever changed points in a car driven with a bad condensor, you'd know what I mean. They pit and fry in no time. Sometimes it's bad enough to leave you at the side of the road with welded points.

But, as you've pointed out, capacitors are a noise reduction tool. Modern circuit boards are full of them, to decouple parts and remove noise. I'm sure ebike controllers are full of them, to suppress transients that are unavoidable in switching circuits.

Lambkin55 04-16-21 07:13 AM
Originally Posted by Pop N Wood (Post 21979218)
Wrap your controller in aluminum foil.

Ideally the device should be shielded and filtered so it doesn't radiate radio energy. The FCC has rules governing these things, but some devices are more compliant than others.

If you can find the source of the static than you might be able to install some RF filters on select lines to reduce the interference. Car ignitions often had "condensers" hooked to the distributor to do this, could be something that simple. But it would be a bit of a science experiment, best bet is to to find some local electronic geek to solve.

Another option might be getting some separation between the AM antenna and the bike electronics. Only so far you can go with that.



Beyond that make sure all of your electrical connections are clean and tight. A dirty connection can cause noise.

BTW I used to listen to football games on AM radio when I rode. Nothing wrong with that.
Hey Pop N Wood

I have been busy of late so am slow to get back but...
I wrapped the controller with aluminum foil, per your suggestion, and BANG no AM interference. I had immediate results! Thanks for the diagnosis.
How I need to find a way to make it look better. Aluminum foil and masking tape looks silly.

Pop N Wood 04-16-21 08:14 AM
If you want to dress it up some use aluminum furnace tape instead of the scotch tape.

I've worked on $15 million test radars that were wrapped up in enough aluminum foil and copper tape that they looked like Christmas turkeys.


All times are GMT -6. The time now is 04:00 PM.


Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.