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18-04-2019, 08:00
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#1
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Registered User
Join Date: Jan 2011
Location: Full time cruiser
Boat: Amel Super Maramu 53
Posts: 219
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SSB Noise
I have an Icom 802 installed with an antenna turner and whip antenna. The installation was done according to guidelines set by DockSide Radio. I am picking up interference, enough to make it difficult to hear long-range broadcasts. I have already isolated a lot of the noise to my MPPT solar panel unit and can turn this off if needed. However, I am still getting noise from one breaker that controls the nav equipment for the vessel. I would prefer not to have to shut this one down every time I wish to use the radio. I haven’t yet traced it to a specific item wired to this breaker because I do not know what to do when I find it. I have ferrites aboard and can install these if needed. But where do I install them? My understanding is the ferrites do not help on power cables, is this correct. Could someone please give me some guidance as to what to look for and how to eliminate the noise. Many thanks!
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18-04-2019, 08:48
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#2
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Registered User
Join Date: Jan 2019
Location: Oceanside Ca
Boat: Lancer 27PS
Posts: 617
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Re: SSB Noise
I think it would help everyone here if you described how you are set up. Meaning...
What kind of ground are you using?
Who, if anything, is sharing that ground?
Are you using coax? If so, from where to where?
Are you using and single wires, i.e. GTO15? From where to where?
On what frequencies do you hear the strongest noise? Or is the noise constant through the entire spectrum?
Noise is generally broadband radiated energy. I suspect you have a bad ground or you are sharing a ground point. I would start by removing the ground on the tuner side and see if the noise abates. Or, possibly find a different ground point.
JMHO
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18-04-2019, 15:04
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#3
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Registered User
Join Date: Jan 2011
Location: Full time cruiser
Boat: Amel Super Maramu 53
Posts: 219
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Re: SSB Noise
Quote:
Originally Posted by Brian.D
I think it would help everyone here if you described how you are set up. Meaning...
What kind of ground are you using?
Who, if anything, is sharing that ground?
Are you using coax? If so, from where to where?
Are you using and single wires, i.e. GTO15? From where to where?
On what frequencies do you hear the strongest noise? Or is the noise constant through the entire spectrum?
Noise is generally broadband radiated energy. I suspect you have a bad ground or you are sharing a ground point. I would start by removing the ground on the tuner side and see if the noise abates. Or, possibly find a different ground point.
JMHO
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Brian,
Thanks for taking the time to answer.
The SSB is grounded to a large dynaplate on the rudder. Nothing else is connect to this plate. Any other equipment and the vessel's bonding system is connected to the keel for a ground.
From the receiver to the tuner: M17/74-RG213 Coaxial Cable (This mil-spec coax cable is used for high frequency signal transmission.)
GTO15 wire is used from the tuner to the antenna. Connections are clean.
The noise is loudest in the middle/lower frequencies.
When you say, "I would start by removing the ground on the tuner side and see if the noise abates." Do you mean the green ground wire at the back of the Icom802 or the wire from the auto antenner tuner to the dynaplate?
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18-04-2019, 15:40
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#4
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Registered User
Join Date: Oct 2010
Location: The boat - New Bern, NC, USA; Us - Kingsport, TN, USA
Boat: 1988 Pacific Seacraft 34
Posts: 1,454
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Re: SSB Noise
For what is worth, our old Simrad IS-15 instruments cause RF noise that infects both our Icom IC-M710 HF radio and pocket size AM radios that share no connection to the boat's electrical system. The problem raises its head when working with weak signals.
Sniffing with the AM radios indicates that the noise originates from the Roblink cables. Years of attempts to eliminate the noise have been unsuccessful, so we just turn them off when they are a bother. The attempts include clamp on ferrites, grounding capacitors, and small inductors. None have been worthwhile.
The newer NMEA 2000 Simrad instruments on the system are quiet as a church mouse.
Bill
AK4PO
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18-04-2019, 15:43
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#5
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Registered User
Join Date: Jan 2019
Location: Oceanside Ca
Boat: Lancer 27PS
Posts: 617
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Re: SSB Noise
You are grounding the radio and the tuner? What is the radio grounded to? The radio already is ground via the black 12vdc wire. It does not need to be grounded again. There is a possibility you have set up a ground loop meaning... The ground lug of the radio is looping back through the dyna plate on the rudder.
Radio transmissions are AC in nature, not DC. So your antenna is 1/2 of the AC radio wave while the water (dyna plate) is the other 1/2. That RF ground is coming from the radio via the coax to the tuner then to the dyna plate.
When I mentioned that noise is generally radiated energy it is because there might be a faulty ground somewhere. Disconnecting the radio ground or the tuner dyna plate ground might stop the noise. But now you would have to find where the noise is being generated. That means turning EVERYTHING off in the boat and then turn on one switch at a time. Eventually you will find the offending item.
Do you have a refer/refrigerator? Hot water heater? Or anything with a coil? Maybe LED lights?
This will be a great exercise in trouble shooting. I envy you... not. LOL
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18-04-2019, 16:33
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#6
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Registered User
Join Date: Jan 2011
Location: Full time cruiser
Boat: Amel Super Maramu 53
Posts: 219
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Re: SSB Noise
Quote:
Originally Posted by Brian.D
You are grounding the radio and the tuner? What is the radio grounded to? The radio already is ground via the black 12vdc wire. It does not need to be grounded again. There is a possibility you have set up a ground loop meaning... The ground lug of the radio is looping back through the dyna plate on the rudder.
Radio transmissions are AC in nature, not DC. So your antenna is 1/2 of the AC radio wave while the water (dyna plate) is the other 1/2. That RF ground is coming from the radio via the coax to the tuner then to the dyna plate.
When I mentioned that noise is generally radiated energy it is because there might be a faulty ground somewhere. Disconnecting the radio ground or the tuner dyna plate ground might stop the noise. But now you would have to find where the noise is being generated. That means turning EVERYTHING off in the boat and then turn on one switch at a time. Eventually you will find the offending item.
Do you have a refer/refrigerator? Hot water heater? Or anything with a coil? Maybe LED lights?
This will be a great exercise in trouble shooting. I envy you... not. LOL
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Brian,
Nothing else interferes with the radio other than something on this one breaker. On this breaker is the ships navigation instruments (depth, wind, gyro compass, 0183 network, etc).
The radio is grounded to the dynaplate, and the auto-turner is also grounded to the dynaplate using the harness supplied by Icom. There is no other ground to the radio.
My question is really, once I find the culprit how do I stop the noise? I really do not want to shut down the ships nav system to use the radio.
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18-04-2019, 16:34
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#7
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Registered User
Join Date: Jan 2011
Location: Full time cruiser
Boat: Amel Super Maramu 53
Posts: 219
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Re: SSB Noise
Quote:
Originally Posted by wsmurdoch
For what is worth, our old Simrad IS-15 instruments cause RF noise that infects both our Icom IC-M710 HF radio and pocket size AM radios that share no connection to the boat's electrical system. The problem raises its head when working with weak signals.
Sniffing with the AM radios indicates that the noise originates from the Roblink cables. Years of attempts to eliminate the noise have been unsuccessful, so we just turn them off when they are a bother. The attempts include clamp on ferrites, grounding capacitors, and small inductors. None have been worthwhile.
The newer NMEA 2000 Simrad instruments on the system are quiet as a church mouse.
Bill
AK4PO
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Bill,
Thanks. But not what I wanted to hear
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18-04-2019, 16:58
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#8
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Registered User
Join Date: Jan 2019
Location: Oceanside Ca
Boat: Lancer 27PS
Posts: 617
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Re: SSB Noise
Well, I would start by disconnecting everything to that circuit. Then one at a time power up a device. We have to ID the offender. It could be complicated like Bill said, or it could be a bad shield in a connecting cable.
Depth, wind, and Gyro are all voltage driven. Depth and gyro are on all the time. Wind is only working when it is windy. So I would eliminate wind. NMEA is serial thus DC. I would eliminate NMEA. So that leave Gyro which might have AC voltage working somewhere in the unit.
Can you shut down the gyro without issues for testing only?
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18-04-2019, 18:00
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#9
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: SSB Noise
Most of us just turn off whatever makes noise, the only problem is if we forget to turn it back on.
It’s usually the fridge
Why not turn the Nav system off?
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18-04-2019, 18:48
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#10
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Registered User
Join Date: Sep 2008
Location: Camden, ME
Boat: A Thistle and a Hallberg-Rassy 36
Posts: 848
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Re: SSB Noise
NMEA signals can certainly generate RF noise, since the signaling is a square wave, chock full of harmonics way up the spectrum. NMEA needs to be transmitted over shielded cable for this reason, even then you can get radiated noise. I would be sure all NMEA cables have shields which are single end grounded, and you might also try ferrites on each end of each NMEA cable.
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18-04-2019, 18:56
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#11
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Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
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Re: SSB Noise
Quote:
Originally Posted by mcerdos
Brian,
Nothing else interferes with the radio other than something on this one breaker. On this breaker is the ships navigation instruments (depth, wind, gyro compass, 0183 network, etc).
The radio is grounded to the dynaplate, and the auto-turner is also grounded to the dynaplate using the harness supplied by Icom. There is no other ground to the radio.
My question is really, once I find the culprit how do I stop the noise? I really do not want to shut down the ships nav system to use the radio.
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The first task is to find the culprit. I am not sure what a 0183 network is. NMEA0183 is a point to point standard. It is not meant to be networked. NMEA2000 is a networking standard.
To find the culprit you have to turn off each device powered by that circuit breaker to find which one(s) cause RF noise. Then when we know that we might be able to offer some suggestions for noise mitigation. I would start with the depth finder.
Be aware that you may end up having to turn off some nav gear during SSB transmissions anyway. Often autopilots, gyros and wind sensors freak out when transmitting on SSB.
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18-04-2019, 22:22
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#12
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Registered User
Join Date: Jan 2019
Location: Oceanside Ca
Boat: Lancer 27PS
Posts: 617
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Re: SSB Noise
Does it sound like a hash, white noise? Or more of a fast pulsating one cylinder motor boat?
The reason I ask is I have one of those homeplug systems that connects one router to another router via the power lines in my house. This network works between 3~30 MHz and is causing a fast motor boat sound on 4, 8, 15, 20 MHz but not on 7 or 14 MHz.
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19-04-2019, 04:33
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#13
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Moderator Emeritus
Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 31,351
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Re: SSB Noise
Quote:
Originally Posted by transmitterdan
Be aware that you may end up having to turn off some nav gear during SSB transmissions anyway. Often autopilots, gyros and wind sensors freak out when transmitting on SSB.
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SSB’s emit a LOT of RF, get near the antenna with a florescent tube, don’t touch the antenna to see what I mean. Mine will sometimes make our LED lights flicker inside of the boat, and they are not powered.
It may not be a bad idea for expensive, sensitive electronics to be powered off during SSB transmissions?
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19-04-2019, 05:31
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#14
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Registered User
Join Date: Nov 2012
Location: La Honda, California
Boat: Beneteau Oceanis 50
Posts: 364
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Re: SSB Noise
I had a similar problem, lots of rf noise when the nav instruments were on. My boat is Raymarine equipped, first generation SeaTalk, and noisy. I put multiple ferrites on each and every cable coming to and from the radio, and the control head. I also put multiple ferites on the SeaTalk cables near the radio. I have more than 25 ferrites on these cables, way more than suggested. I also put a choke tube on the antenna line coming from the radio. All this did solve the RF noise problem. Maybe you have already done this, I couldn't tell from you description.
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19-04-2019, 06:20
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#15
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Registered User
Join Date: Oct 2011
Boat: Valiant 42
Posts: 6,008
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Re: SSB Noise
Quote:
Originally Posted by a64pilot
SSB’s emit a LOT of RF, get near the antenna with a florescent tube, don’t touch the antenna to see what I mean. Mine will sometimes make our LED lights flicker inside of the boat, and they are not powered.
It may not be a bad idea for expensive, sensitive electronics to be powered off during SSB transmissions?
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I don’t think it will damage electronics. But it can cause some sensors to give wrong readings. An electronic compass is often pushed off course by the SSB. So autopilots sometimes make crazy course changes when the SSB is transmitting.
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