I am about to start a major rewire on the boat. Which brings up some
ideas and questions.

Idea/question 1. I have seen those expensive power filters for boating
electronics. Why can't I just build a dedicated power buss and drop
some capacitors across the power feeds to each instrument? As in going
back to when we had to build our own power supplies for computer floppy
drives.

The electronics I will be trying to protect are ...
VHF
GPS/Chartplotter combo
Scanning sonar (Interphase)
Radar
SSB
Autopilot

And I may put a second radar and/or scanning sonar at the upper helm.

Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

Earl Haase

Not familiar with the problem you are referring to. What expensive filters
are you refering to? I've never come across what you seem to be asking
about.

Doug
s/v Callista

"Earl Haase" wrote in message
...
I am about to start a major rewire on the boat. Which brings up some
ideas and questions.

Idea/question 1. I have seen those expensive power filters for boating
electronics. Why can't I just build a dedicated power buss and drop
some capacitors across the power feeds to each instrument? As in going
back to when we had to build our own power supplies for computer floppy
drives.

The electronics I will be trying to protect are ...
VHF
GPS/Chartplotter combo
Scanning sonar (Interphase)
Radar
SSB
Autopilot

And I may put a second radar and/or scanning sonar at the upper helm.

Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

Earl Haase

In article ,
Earl Haase wrote:

The electronics I will be trying to protect are ...
VHF
GPS/Chartplotter combo
Scanning sonar (Interphase)
Radar
SSB
Autopilot

And I may put a second radar and/or scanning sonar at the upper helm.

Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

Earl Haase


What are you protecting the above equipment from? Power spikes?
RFI? Bird ****? Just what?

Bruce in alaska
--
add a 2 before @

Doug,
Given your previous posts on this group I'm a little surprised you
haven't heard of or seen these before. The power filters I'm talking
about are also called noise filters. They connect to the power lines
going to the boat electronics to filter out problems caused by other
equipment. This could be other electronics like maybe using the chart
plotter interferes with use of the VHF. Or you might get noise from the
engine ignition system or alternator. Maybe running your windshield
wipers wipes out your VHF so you can't talk and look through the
windshield at the same time. There are also filters for this equipment
too in order to keep the noise coming out of these from getting into the
system in the first place. You can check online at the Newmar company
site for examples. They run from around $70 per instrument up to
hundreds or even a thousand each dollars depending on what system you
choose.

Bruce,
In the past you have posted here about all your experience in
electronics repair. I am confident that you knew what I was asking.
After all, I just asked a couple of questions in order to get the
opinion of others who would hopefully share their collective knowledge.
I don't know why this ****ed you off so much but if you don't want to
play nice please feel free not to play at all.

Earl

Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

My hi-tech Xantrex / Statpower battery chargers produce terrible amounts on
noise on my shortwave radios. I've been told that twisted pairs from the
outputs to the batteries may reduce this. Not got up the engergy to do the
re-wiring yet. By the way, this noise is radiated rather than transmitted
down the wire with the DC.

Using twisted pairs for wire carrying clean DC, e.g. from batteries only, is
just extra work for no benefit. I suppose some electronics might feed noise
back up the DC line but I would think this unlikely in newer
equipment.......but maybe not battery chargers?

"Earl Haase" wrote in message
...
I am about to start a major rewire on the boat. Which brings up some
ideas and questions.

Idea/question 1. I have seen those expensive power filters for boating
electronics. Why can't I just build a dedicated power buss and drop
some capacitors across the power feeds to each instrument? As in going
back to when we had to build our own power supplies for computer floppy
drives.

The electronics I will be trying to protect are ...
VHF
GPS/Chartplotter combo
Scanning sonar (Interphase)
Radar
SSB
Autopilot

And I may put a second radar and/or scanning sonar at the upper helm.

Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

Earl Haase

Bruce,

Have you actually had problems as extreme as you are relating to
here or have you just been reading the catalogs and seeing
products that you feel will keep ypu out of trouble?

Noise filters I have heard of. Never heard them referred to as
power filters though. I've never had to resort to anything other than a
few ferrite beads to solve noise problems. Some minor comments
below.

Doug
s/v Callista

"Earl Haase" wrote in message
...
Doug,
Given your previous posts on this group I'm a little surprised you
haven't heard of or seen these before. The power filters I'm talking
about are also called noise filters. They connect to the power lines
going to the boat electronics to filter out problems caused by other
equipment.

OK.

This could be other electronics like maybe using the chart
plotter interferes with use of the VHF.

Have both and no interference between them. Most electronics are
equipped to prevent noise from being introduced back into the power
supply lines.

Or you might get noise from the
engine ignition system or alternator.

I have a diesel engine, but never had any problem with alternator noise.

Maybe running your windshield
wipers wipes out your VHF so you can't talk and look through the
windshield at the same time.

Doubtful that it keeps you from talking. Might keep you from receiving
though. Anyway, what is a windshield wiper?

There are also filters for this equipment
too in order to keep the noise coming out of these from getting into the
system in the first place. You can check online at the Newmar company
site for examples. They run from around $70 per instrument up to
hundreds or even a thousand each dollars depending on what system you
choose.

Wow! Seems like snake oil to me. I have a pretty full complement of
electronics on board and have had no problems at all until I installed
email via ham using a laptop. The high power HF emissions did cause
some problems with the computer. A few ferrite beads and an isolator
solved those problems.

Bruce,
In the past you have posted here about all your experience in
electronics repair. I am confident that you knew what I was asking.
After all, I just asked a couple of questions in order to get the
opinion of others who would hopefully share their collective knowledge.
I don't know why this ****ed you off so much but if you don't want to
play nice please feel free not to play at all.

Earl

Inverters and switch mode charges can emit alot of noise. But you are
correct that the noise is not sent back up the supply lines. Alot of the
noise enters the VHF or HF radios via the antenna or unshielded portions
of the internals. Typical solution is to shut down the inverter or charger
while using the radio. Alot cheaper than spending alot of money on
fancy filters that only reduce the problem rather than solving it.

Doug
s/v Callista

"Gordon Wedman" wrote in message
news:vG7Qc.30972$hw6.24936@edtnps84...
Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

My hi-tech Xantrex / Statpower battery chargers produce terrible amounts
on
noise on my shortwave radios. I've been told that twisted pairs from the
outputs to the batteries may reduce this. Not got up the engergy to do
the
re-wiring yet. By the way, this noise is radiated rather than transmitted
down the wire with the DC.

Using twisted pairs for wire carrying clean DC, e.g. from batteries only,
is
just extra work for no benefit. I suppose some electronics might feed
noise
back up the DC line but I would think this unlikely in newer
equipment.......but maybe not battery chargers?

"Earl Haase" wrote in message
...
I am about to start a major rewire on the boat. Which brings up some
ideas and questions.

Idea/question 1. I have seen those expensive power filters for boating
electronics. Why can't I just build a dedicated power buss and drop
some capacitors across the power feeds to each instrument? As in going
back to when we had to build our own power supplies for computer floppy
drives.

The electronics I will be trying to protect are ...
VHF
GPS/Chartplotter combo
Scanning sonar (Interphase)
Radar
SSB
Autopilot

And I may put a second radar and/or scanning sonar at the upper helm.

Question 2. When and where should I use twisted pairs and why not just
twist everything, everywhere?

Earl Haase

In article ,
Earl Haase wrote:

Bruce,
In the past you have posted here about all your experience in
electronics repair. I am confident that you knew what I was asking.
After all, I just asked a couple of questions in order to get the
opinion of others who would hopefully share their collective knowledge.
I don't know why this ****ed you off so much but if you don't want to
play nice please feel free not to play at all.

Earl



I am not '****ed Off" at all, I just want a clarifacation on what you
are trying to do. We get all kinds, asking for advice, and most can't
detail what they really want, let alone ask intelligent questions, about
subjects they are just learning about.

Now, first off, you NEVER eliminate noise at the receiver, but ALWAYS
eliminate it at the SOURCE. Filtering the power leads of marine
equipment, is only effective, IF that is where the noise is being
radiated FROM. ie Get a GOOD filter on your Alternator Output,
to keep it from using the DC Power System as a Radiating Antenna,
to the rest of the boat and all the folks in the same harbour.
Put a Cap ACROSS all the Brushed DC Motors, onboard wheather they are
noisy now or not, and do it as close to the motor as possible, and NOT
from each lead to the motor case. Most GOOD marine electronics has a
"Ground Lug" on the case. Use them, to connect each case to a common
LOW IMPEDANCE Grounding Point for electronics. If you have a "Plastic
Boat", build a common LOW IMPEDANCE Grounding Point for electronics,
before you do anything else. For SSB Radios, move the Antenna Tuner
as close to the RF Ground as possible, and keep it as far from the rest
of the electronics as practicable. Radars need to have their cases
connected to the common LOW IMPEDANCE Grounding Point, and make VERY
sure that you keep the Grounding Shield of the Interconnection Cable
between the display and antenna good and tight on BOTH ends. Put Caps
ACROSS the drive motor of your AutoPilot, and the Switching Relay
Contacts if your pilot has them. If you have multiple VHF Radio's,
make sure that the antennas are seperated by 3 or 4 wavelengths, both
vertically and horozontally, so as to eliminate direct coupling between
the radio's. If you have multiple MF/HF Radio's, design and build a
complete PTT/Antenna Break Interswitch system between the radios. If you
support multiple RADARS on the same Band, seperate them vertically, so
as to keep their 25 degree vertical beamwidth antennas from seeing each
other. Mount Inmarsat Antennas way from GPS Antennas, as they use the
same bands.


Bruce in alaska who gives away $1000US advice, for free, to
those who ask
--
add a 2 before @

Doug,

Thanks for the response. All the instruments I am installing are new.
They are going on a 1970 Chris Craft that is nearing completion of a
four year restoration. I am looking at filtering to avoid problems
before they start. The boat is in Tampa and when I get it in the water
I will be leaving to take the boat back home to the Caribbean. I will
not have time to play with things very much before leaving so I want to
fix it before it breaks. The only shake down will be as I cross the
state to the east coast through the river & canal.

Tell me more about these ferrite beads. An Autohelm autopilot I have
(will not be part of this installation) included installation
instructions to use them. The instructions did not go into detail on
why they insisted I needed them.

Thanks again,

Earl

Earl,

I've never come across noise problems to the extent that you
are expecting. I wouldn't go spending alot of money on filtering
until you find a problem bad enough to warrant it. Specifically,
I've never had any problems with instruments and VHF. I do get
some noise from the inverter into the SSB. The inverter is running
the computer but I can just turn it off and let it run on its internal
battery. The noise is only a problem when picking out weak stations.

A ferrite bead is just a collar of ferrite that clamps around a wire. They
filter out any noise that may be induced in the wire. I have them
in some of the wires leading to the autopilot modules. The power leads
to the SSB and the computer. They only cost a few bucks each.

Doug
s/v CAllista

"Earl Haase" wrote in message
...
Doug,

Thanks for the response. All the instruments I am installing are new.
They are going on a 1970 Chris Craft that is nearing completion of a
four year restoration. I am looking at filtering to avoid problems
before they start. The boat is in Tampa and when I get it in the water
I will be leaving to take the boat back home to the Caribbean. I will
not have time to play with things very much before leaving so I want to
fix it before it breaks. The only shake down will be as I cross the
state to the east coast through the river & canal.

Tell me more about these ferrite beads. An Autohelm autopilot I have
(will not be part of this installation) included installation
instructions to use them. The instructions did not go into detail on
why they insisted I needed them.

Thanks again,

Earl