Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 29-03-2012, 06:23   #1
Registered User

Join Date: Nov 2010
Location: Key West, Fl.
Boat: 1978 Prout Quest 31
Posts: 94
RFI on VHF Radio

I have a popping noise on my VHF that can not be squealched out completely. The cause is from my Air-X wind generator.

Is there a filter or choke that can be installed to eliminate this problem? I have readthat twisting the leads can eleminate this problem, but really don't want to pull all wires back to pole mounted wind turbine and re-pull after twisting. Big Pita

Any info or advise will be welcome, I have done some research on this, but am challenged on the technical info and jargon and the install process or devices to use
__________________

__________________
tybee22 is offline   Reply With Quote
Old 29-03-2012, 06:52   #2
Registered User
 
Nemo55's Avatar

Join Date: Feb 2012
Location: Punta Banda, Ensenada. and Canada
Boat: 28Ft Piver Encore, Tri-Maran, Anchored in San Diego.
Posts: 728
Send a message via Skype™ to Nemo55
Re: RFI on VHF radio

A Capacitor installed on the power lead of the radio and case grounded to the radio Mounting bracket may do the trick.
__________________

__________________
"The Truth Shall set you Free....But First it will Piss You Off"

http://nemo1955.blogspot.ca/
Nemo55 is offline   Reply With Quote
Old 29-03-2012, 06:57   #3
Registered User
 
Nemo55's Avatar

Join Date: Feb 2012
Location: Punta Banda, Ensenada. and Canada
Boat: 28Ft Piver Encore, Tri-Maran, Anchored in San Diego.
Posts: 728
Send a message via Skype™ to Nemo55
Re: RFI on VHF radio

Another possible solution is to power the Radio directly from the battery,,as the battery will act like one giant capacitor.
__________________
"The Truth Shall set you Free....But First it will Piss You Off"

http://nemo1955.blogspot.ca/
Nemo55 is offline   Reply With Quote
Old 29-03-2012, 07:25   #4
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: RFI on VHF radio

Try some ferrite beads on the generator power leads as close as possible to the generator. See Ferrite bead - Wikipedia, the free encyclopedia

If that doesn't do the trick (and you have tried Nemo's advice), you might have to open up the generator and start adding capacitors across the output wiring.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 29-03-2012, 07:28   #5
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
Re: RFI on VHF radio

Id want to put a scope on it first, wonder what characteristics it has, ( its opening the squelch mind you, so it must be big).

Dave
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 29-03-2012, 08:09   #6
Registered User

Join Date: Nov 2010
Location: Key West, Fl.
Boat: 1978 Prout Quest 31
Posts: 94
Re: RFI on VHF radio

Thanks for the quick replies folks, but as I started to run a direct wire to radio from battery I was shutting power down to each system one by one and discovered the interferance is from the MPPT 250 charge controller used in my solar system, not the wind generator.

When I removed the fuse from that systems circit all RFI stopped. I blamed wrong devise. I have contacted BZ Prouducts for solution and am awaiting a reply from them.

Does anyone know of a way to eliminate RFI from this type of source?
__________________
tybee22 is offline   Reply With Quote
Old 29-03-2012, 08:21   #7
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
Re: RFI on VHF radio

This is most likely a harmonic of the switching frequency used in the MPPT controllers. It is probably quite a high frequency. Ferrite beads are your friend. ( it could be air coupled , if the two devices were close). It can be hard to remove it completely.

Make sure the VHF has a good ground and supply , preferably direct to the battery ( with breakers or fuses).

dave
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 29-03-2012, 08:33   #8
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,331
Re: RFI on VHF radio

Quote:
Originally Posted by goboatingnow View Post
This is most likely a harmonic of the switching frequency used in the MPPT controllers. It is probably quite a high frequency. Ferrite beads are your friend. ( it could be air coupled , if the two devices were close). It can be hard to remove it completely.

Make sure the VHF has a good ground and supply , preferably direct to the battery ( with breakers or fuses).

dave
Can't argue with this advice and if it is air coupled, confirm if it is being picked up by the VHF antenna or via the coax or direct into the radio etc; then relocating the offending items (controller, coax, antenna, radio etc) or shielding the controller.

But I agree with Dave, go the ferrite way first as mostly the RFI is radiated by the wiring.
__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 29-03-2012, 08:58   #9
Registered User

Join Date: Nov 2010
Location: Key West, Fl.
Boat: 1978 Prout Quest 31
Posts: 94
Re: RFI on VHF radio

Will be researching ferrite beads, any suggestions of size or type to use. I think I will also move radio to differant location as it could very well be air coupled as all wiring, radio and antenna leads are in the same cabinet in very close proximitry to each other. This is not by my design, it is how the set-up was when I bought the boat. Only thing I have done differant was to install charge controller when I upgraded the solar panels as old one was not big enough. The solar system circut does not run through the main system, but is isolated from eveything and sepperatly fused with out-put back to house bank and divert to engine bank.
__________________
tybee22 is offline   Reply With Quote
Old 29-03-2012, 09:08   #10
Registered User
 
Rhapsody-NS27's Avatar

Join Date: Oct 2010
Location: VA, boat: Deale, MD
Boat: 1981 Nor'sea 27
Posts: 1,409
Re: RFI on VHF radio

Quote:
Originally Posted by tybee22 View Post
I think I will also move radio to differant location as it could very well be air coupled as all wiring, radio and antenna leads are in the same cabinet in very close proximitry to each other.
This was about to be my advice but you're already on it. Moving the radio (and cables) might help reduce or eliminate the issue.

Let us know how it goes.
__________________
Daniel - Rhapsody Blog,
“A sailor’s joys are as simple as a child’s.” — Bernard Moitessier
"I don't need therapy, I just need my boat"
Rhapsody-NS27 is offline   Reply With Quote
Old 29-03-2012, 09:13   #11
Nearly an old salt
 
goboatingnow's Avatar

Cruisers Forum Supporter

Join Date: Jun 2009
Posts: 13,649
Images: 3
Re: RFI on VHF radio

This is quite a complex topic, so a few rules of thumb,

In general try and get at least one turn through the ferrite, and size the ferrite as close as possible to facilitate that

Select a ferrite with the highest impedance at the desired suppression frequency, since you will not have an idea, its a hit and miss affair.

It may take multiple ferrites to have an effect.

The signal could be coupling in via the Mike cable. does the if its disconnected does the squelch still open. PWM switching frequencies have risen to about 400Khz, so it will be some harmonic of that but hard to say, buy a selection of ferrites they arnt expensive. Put them on the VHF power leads close to VHF
put them on the input leads and output leads of the MPPT controller again close to the controller.

The simplest , but least effective are "clamp" type ferrites that dont require turns or the wire to be disconnected to fit them. buy a few an try them, its a bit hit and miss, but without a scope or better yet a spectrum analyzer its hard to get quantifiable data.

Put them on the mike lead ( if possible).

dave
__________________
Check out my new blog on smart boat technology, networking and gadgets for the connected sailor! - http://smartboats.tumblr.com
goboatingnow is offline   Reply With Quote
Old 29-03-2012, 09:39   #12
Registered User

Join Date: Nov 2010
Location: Key West, Fl.
Boat: 1978 Prout Quest 31
Posts: 94
Re: RFI on VHF radio

I'm certinally getting some great advise from you folks THANKS. Will be going to shore to pick-up wire and antena lead to relocate radio. Only marine electronics shop in Key West closed years ago so will source out some of the local hams for advise. If that fails I will drive up to Marathon and see the guys at he shop up there, 45 mile trip each way.

Meanwhile I am certainly getting an education as I reseach the ferrite bead solution. Wil post results as I have them. Once again thank you for all the information, tips and suggestions
__________________
tybee22 is offline   Reply With Quote
Old 29-03-2012, 10:55   #13
Moderator
 
Paul Elliott's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 3,867
Images: 4
Re: RFI on VHF Radio

Here's a link to a presentation I recently gave about SSB and satphones, including a section on EMI: SHTP Communications 2012.

About halfway through it I give some details on appropriate ferrites and their application. The particular ferrite I mention is optimized for SSB frequencies, but is still very effective in the lower VHF range, where you are having the problem.
__________________
Paul Elliott, S/V VALIS - Pacific Seacraft 44 #16 - Friday Harbor, WA
www.sailvalis.com
Paul Elliott is online now   Reply With Quote
Old 29-03-2012, 11:17   #14
mrm
Registered User

Join Date: Feb 2011
Location: Poland, EU
Boat: crew on Bavaria 38 Cruiser
Posts: 651
Re: RFI on VHF radio

Quote:
Originally Posted by tybee22 View Post
Meanwhile I am certainly getting an education as I reseach the ferrite bead solution. Wil post results as I have them. Once again thank you for all the information, tips and suggestions
Had a similar problem with a noise from my laptop blanking weatherfax reception on my el cheapo SSB receiver. It turned out the noise was being coupled via audio cable. Took a picture of my solution for you. Works very well.

As advised already, try to get more turns through the ferrite ring. The reason (in very simplified terms) is, that the 'resistance' presented to RFI is proportional to a square of a number of turns. Good luck
Attached Thumbnails
Click image for larger version

Name:	ferrite.jpg
Views:	82
Size:	41.0 KB
ID:	39292  
__________________

__________________
mrm is offline   Reply With Quote
Reply

Tags
radio, vhf

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Shoestring Sailors (Cruising on $500 per month - part II) David_Old_Jersey General Sailing Forum 1355 13-11-2017 17:32
Automated VHF "Radio Check" Service is Expanding Waterway Guide Marine Electronics 9 30-03-2012 06:02
RFI on VHF Radio tybee22 Marine Electronics 13 29-03-2012 11:17
Crossing Bars on NSW's North coast 44'cruisingcat Pacific & South China Sea 11 29-03-2012 01:12



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 10:17.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.