ausmini :: View topic - Quieting electrical RF noise?

Hey everyone,

I am wondering if anyone can advise about reducing RF noise, possibly from the alternator? Possibly from coil and leads?

Firstly, let me clarify, I am using a BATTERY powered handheld 5W UHF radio, it is NOT powered through the Mini's 12v electrics.

The UHF radio has an external Mini-roof-mounted antenna. It runs perfectly when the car is off. It is difficult to use/hear when the car is running due to interference. I think it's worse at higher RPM.

I've run the coax well away from any power cables (along the RH side roof line). I've tried normal full length, coiled up coax cable. I've tried shortening it to the bare minimum needed to get from antenna to unit. Still the same.

Any ideas on how to reduce the RF interference? Would an inline noise filter from the alternator work, or would that maybe just clean up the electrical signal rather than the RF interference?

Cheers!

Sent from my Pixel 2 XL using Tapatalk

Author:	Morbo28 [ Sat Feb 23, 2019 7:38 pm ]
Post subject:	Quieting electrical RF noise?
Hey everyone, I am wondering if anyone can advise about reducing RF noise, possibly from the alternator? Possibly from coil and leads? Firstly, let me clarify, I am using a BATTERY powered handheld 5W UHF radio, it is NOT powered through the Mini's 12v electrics. The UHF radio has an external Mini-roof-mounted antenna. It runs perfectly when the car is off. It is difficult to use/hear when the car is running due to interference. I think it's worse at higher RPM. I've run the coax well away from any power cables (along the RH side roof line). I've tried normal full length, coiled up coax cable. I've tried shortening it to the bare minimum needed to get from antenna to unit. Still the same. Any ideas on how to reduce the RF interference? Would an inline noise filter from the alternator work, or would that maybe just clean up the electrical signal rather than the RF interference? Cheers! Sent from my Pixel 2 XL using Tapatalk

Author:	Goldbrocade_62 [ Sat Feb 23, 2019 9:05 pm ]
Post subject:	Re: Quieting electrical RF noise?
Morbo28 wrote: Hey everyone, I am wondering if anyone can advise about reducing RF noise, possibly from the alternator? Possibly from coil and leads? Firstly, let me clarify, I am using a BATTERY powered handheld 5W UHF radio, it is NOT powered through the Mini's 12v electrics. The UHF radio has an external Mini-roof-mounted antenna. It runs perfectly when the car is off. It is difficult to use/hear when the car is running due to interference. I think it's worse at higher RPM. I've run the coax well away from any power cables (along the RH side roof line). I've tried normal full length, coiled up coax cable. I've tried shortening it to the bare minimum needed to get from antenna to unit. Still the same. Any ideas on how to reduce the RF interference? Would an inline noise filter from the alternator work, or would that maybe just clean up the electrical signal rather than the RF interference? Cheers! Sent from my Pixel 2 XL using Tapatalk Sounds like you need a smart electronics man Ian B are you awake

Author:	Morbo28 [ Sun Feb 24, 2019 9:43 am ]
Post subject:	Re: Quieting electrical RF noise?
I might look on a UHF/electronics site perhaps if there's no elec-chickens on here. I guess it's more of a electrical thing rather than a Mini thing. Sent from my Pixel 2 XL using Tapatalk

Author:	9YaTaH [ Sun Feb 24, 2019 2:29 pm ]
Post subject:	Re: Quieting electrical RF noise?
Did you terminate the coax connections? poor earths and poorly shielded coax can cause the interference you describe... Ferrite Beads (not for Hippies!) https://www.jpole-antenna.com/shop/snap ... -cart=2508

Author:	Ian_B [ Sun Feb 24, 2019 4:27 pm ]
Post subject:	Re: Quieting electrical RF noise?
Scream sound is from alternator Static pop sound is from spark UHF radios arent prone to this .Put a filter close to the radio in line Will fix all Let me know how you go

ausmini https://www.ausmini.com/forums/

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Author:	Ian_B [ Sun Feb 24, 2019 4:30 pm ]
Post subject:	Re: Quieting electrical RF noise?
If your coax has a problem a reflected power SWR test will prove it however FM radios use a thing called limiting They arent prone to interference .It is alternator stuff thru power lead.

Author:	Morbo28 [ Sun Feb 24, 2019 6:19 pm ]
Post subject:	Re: Quieting electrical RF noise?
Ian_B wrote: Scream sound is from alternator Static pop sound is from spark UHF radios arent prone to this .Put a filter close to the radio in line Will fix all Let me know how you go Hi Ian, thanks for the advice. When you say to put a filter inline, what do you mean? Do you mean a ferrite filter, on the coax? Note that the UHF does not get power from the Mini 12v system, it has its own battery. EDIT: the ordered the ferrite beads, thanks 9ya and Ian. I got 5mm to try single pass and 13mm ones to try multiple loops. Cheers, let's see how this goes Sent from my Pixel 2 XL using Tapatalk

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