SSB noise
 

I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.
krj

SSB noise
 

"krj" wrote in message
...
I just finished installing an SSB on my boat. When I turn on my freezer I
get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had this
problem. I think I remember Gordon West writing about this problem in one
of the sailing mags. but can't remember which one or when.
krj

SSB noise
 

krj wrote:
I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.

Sail magazine, June 2005.

Gordon West recommended:

1. Wrap compressor and controller in copper foil and ground the foil to
the compressor's metal mounting legs;
2. Install ferrite chokes on the control wires coming out of the
controller, as close as possible to the plastic controller box; and
3. Wrap controller box with copper screen from a hardware store.

Cheers

SSB noise
 

wrote:
krj wrote:
I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.

Sail magazine, June 2005.

Oops! It was the July issue, 2005, not June.

Cheers

Bil

SSB noise
 

SSB noise
 

krj wrote:
I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.
krj

I'm not familiar with the Gordon West article, but the following may help.

Digital thermostats often use microcontrollers capable of generating RF
interference. That is more likely the problem than the compressor itself.

The interference can be transmitted to the SSB either by radiation, in
which case the SSB is picking it up via its antenna, or by conduction
through the 12 VDC wiring.

To test the former possibility, radiation, simply remove the coax
connector from the SSB and carefully short the center conductor on the
SSB to the grounded outer conductor. Use as short a wire as possible and
try not to touch it. There is no risk whatever to the SSB or to you. The
idea is that your body not serve as an "antenna". Next, listen for
freezer noise on the SSB. If it is gone or even reduced significantly,
then a good portion of the noise is being radiated. Short of providing
RF shielding of the freezer electronics (which may be quite a task) your
best option may be to contact the manufacturer. These units are often
constructed with explicit RFI reduction circuits/components, which could
be defective in your unit.

If the noise is not being radiated, then it is being conducted via the
12 volt wiring. Bypass capacitors at the 12 volt connections to the
freezer (right at the unit itself) may cure the problem. Chokes and RF
filters could also be added to the SSB 12 volt line, although they would
have to be able to handle the current drawn by the SSB during transmit:
20- 30 amps.

There is a lot of useful info on the web, but it is important to know
how the interference is reaching the SSB. Meanwhile, maybe someone will
remember the Gordon West article.

Good luck.

Chuck

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SSB noise
 

This has been discussed on Rparts forum a couple of times. The power unit
of the BD series of compressors is a variable frequency inverter and is
notorious for creating RF noise. Danfoss makes an aluminum shielded model
but they are hard to find and don't help with conducted noise. The digital
thermostat is not normally a source.

Some things that will help are ferrite chokes on all wires going to the
power unit to reduce conducted noise. You may have to experiment with the
size to cut the frequencies that you need. Also lining the compressor
locker with metal screening tied to ground reduces radiated noise.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"krj" wrote in message
...
I just finished installing an SSB on my boat. When I turn on my freezer I
get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had this
problem. I think I remember Gordon West writing about this problem in one
of the sailing mags. but can't remember which one or when.
krj

SSB noise
 

krj wrote in news:A%Ihh.1397$cB6.766
@bignews7.bellsouth.net:

I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.
krj

I wish you luck with the shielding. I used to sail on an Endeavour 35
with an Adler-Barbour ice box cold plate that just tore up VHF Channel
16, of all channels, with a pulsing noise. I'm on an Amel Sharki 41
ketch and have installed an Icom M802/AT-140 and insulated backstay on
the main. On this boat the noise source is a Guest dual 10A battery
charger that makes broadband noise across the HF band very strong.
Luckily, it is off at sea.

To shield that fridge unit, you'd need screen box (It doesn't have to be
copper. Aluminum will work fine.) with proper feedthrough capacitors for
each individual wires where it feeds through the box. The ferrite
absorbers, while useful, will not stop the radiation that must be bled
off INSIDE the box, to the box itself. This, in effect, creates a
"screen room" we had in every calibration laboratory I ever worked in.
In the lab, we had to protect the measurements from RF sources outside
the screen room. The 5KW AM radio station just outside Charleston Naval
Shipyard had no signal, at all, inside the room with the door closed.
This is what you are trying to create. Feed through capacitors are a
straight wire through the center of a low impedance capacitor from that
wire to the outside case of it that is threaded to connect it to the
screen box. The signal coming out the wire couples harmlessly through
the capacitor to the INSIDE of the box. The AC and control signals are
much lower in frequency so very little of them couples through to the
screen and they escape the box. An additional ferrite absorber will
attenuate anything that escapes further.

Best of luck to you. You'll find more noise sources as time goes along.
Anything in that boat that has any kind of switching creates it. Your
NMEA data network to the instruments is also a prime source of HF noise
because the manufacturers go on-the-cheap and use unbalanced outputs,
grounding one side of what should be + and - phased signal lines that
were supposed to balanced out its radiation. Now with even 1 ground on -
NMEA data lines, it radiates like hell the whole time the NMEA stuff is
running. Add that to the wires wrapped around screws and all unshielded,
again on-the-cheap, and it makes it much worse. You'll find NMEA's
signal all across the HF bands at regular intervals.

Larry

SSB noise
 

That "morse code" sound is a NEMA sentence bleeding into 12V wiring
through an improper connection. Check out this excellend site for info.
on how to check and correct.
http://www.shipmodul.com/en/connections.html

SSB noise
 

That "morse code" sound is a NMEA sentence bleeding into 12V wiring
through an improper connection. Check out this excellend site for info.

on how to check and correct.
http://www.shipmodul.com/en/connections.html

SSB noise
 

Keith wrote:
That "morse code" sound is a NEMA sentence bleeding into 12V wiring
through an improper connection. Check out this excellend site for info.
on how to check and correct.
http://www.shipmodul.com/en/connections.html

I don't think a Danfoss BD-50 compressor uses NEMA anyplace. That's the
only equipment turned on except for the SSB. The noise is radiated, NOT
coming through the 12V wiring. Disconnected the antenna from the SSB and
the noise goes away. Of course, the station being monitored goes away
alswo with no antenna.

SSB noise
 

Glenn Ashmore wrote:
This has been discussed on Rparts forum a couple of times. The power unit
of the BD series of compressors is a variable frequency inverter and is
notorious for creating RF noise. Danfoss makes an aluminum shielded model
but they are hard to find and don't help with conducted noise. The digital
thermostat is not normally a source.

Some things that will help are ferrite chokes on all wires going to the
power unit to reduce conducted noise. You may have to experiment with the
size to cut the frequencies that you need. Also lining the compressor
locker with metal screening tied to ground reduces radiated noise.

Glenn,
You are right. It is not the digital thermostat. I disconnected the
thermostat leads from the compressor module and put a jumper between the
terminals to turn on the compressor. The noise is still there. It is
being radiated. I have clamp on ferrites on all the wires to the
thermostat, power leads, etc. Any idea where to purchase the shielded
module. The local marine refrigeration shop didn't seem to know anything
about it.
krj

SSB noise
 

There are 4 different electronic modules for the BD series.:
You probably have the standard 101N0210 single speed with the plastic box.
The Danfoss part number for the single speed shielded module is 101N0220.
The 101N0300 is the AEO variable speed with plastic box and the 101N500 is
AEO with shield.

The AEO future saves a bunch of amp hours by adjusting compressor speed to
the load but the single speed models can be hooked to the Frigoboat SSC and
get the same optimization with a slightly better algorithm. They both work
on the principle that the system is most efficient when it runs for long
cycles at the lowest speed but the SSC has an override to run at full speed
for chill down.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"krj" wrote in message
...
Glenn Ashmore wrote:
This has been discussed on Rparts forum a couple of times. The power
unit of the BD series of compressors is a variable frequency inverter and
is notorious for creating RF noise. Danfoss makes an aluminum shielded
model but they are hard to find and don't help with conducted noise. The
digital thermostat is not normally a source.

Some things that will help are ferrite chokes on all wires going to the
power unit to reduce conducted noise. You may have to experiment with
the size to cut the frequencies that you need. Also lining the
compressor locker with metal screening tied to ground reduces radiated
noise.

Glenn,
You are right. It is not the digital thermostat. I disconnected the
thermostat leads from the compressor module and put a jumper between the
terminals to turn on the compressor. The noise is still there. It is being
radiated. I have clamp on ferrites on all the wires to the thermostat,
power leads, etc. Any idea where to purchase the shielded module. The
local marine refrigeration shop didn't seem to know anything about it.
krj

SSB noise
 

Glenn Ashmore wrote:
There are 4 different electronic modules for the BD series.:
You probably have the standard 101N0210 single speed with the plastic box.
The Danfoss part number for the single speed shielded module is 101N0220.
The 101N0300 is the AEO variable speed with plastic box and the 101N500 is
AEO with shield.

The AEO future saves a bunch of amp hours by adjusting compressor speed to
the load but the single speed models can be hooked to the Frigoboat SSC and
get the same optimization with a slightly better algorithm. They both work
on the principle that the system is most efficient when it runs for long
cycles at the lowest speed but the SSC has an override to run at full speed
for chill down.

Glenn,
Yes, I checked the module and it is the 101N0210. I guess the next task
is to find someone in Ft. Lauderdale who can get the 101N220 module.
Hope it isn't a BOATbuc to get a shielded moudle. You sure changing the
module will solve the problem?
krj

SSB noise
 

Keith wrote:
That "morse code" sound is a NMEA sentence bleeding into 12V wiring
through an improper connection. Check out this excellend site for info.

on how to check and correct.
http://www.shipmodul.com/en/connections.html


Good point. Microcontroller RFI sure doesn't sound like morse code. I
assumed the OP was certain the freezer was causing the RFI. If that is
not the case, this may be a costly venture. I would urge definitive
isolation of the interference before attempting a cure.


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SSB noise
 

There are 4 different electronic modules for the BD series.:
You probably have the standard 101N0210 single speed with the plastic box.
The Danfoss part number for the single speed shielded module is 101N0220.
The 101N0300 is the AEO variable speed with plastic box and the 101N500 is
AEO with shield.

The AEO feature saves a bunch of amp hours by adjusting compressor speed to
the load but the single speed models can be hooked to the Frigoboat SSC and
get the same optimization with a slightly better algorithm. They both work
on the principle that the system is most efficient when it runs for long
cycles at the lowest speed but the SSC has an override to run at full speed
for chill down.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"krj" wrote in message
...
Glenn Ashmore wrote:
This has been discussed on Rparts forum a couple of times. The power
unit of the BD series of compressors is a variable frequency inverter and
is notorious for creating RF noise. Danfoss makes an aluminum shielded
model but they are hard to find and don't help with conducted noise. The
digital thermostat is not normally a source.

Some things that will help are ferrite chokes on all wires going to the
power unit to reduce conducted noise. You may have to experiment with
the size to cut the frequencies that you need. Also lining the
compressor locker with metal screening tied to ground reduces radiated
noise.

Glenn,
You are right. It is not the digital thermostat. I disconnected the
thermostat leads from the compressor module and put a jumper between the
terminals to turn on the compressor. The noise is still there. It is being
radiated. I have clamp on ferrites on all the wires to the thermostat,
power leads, etc. Any idea where to purchase the shielded module. The
local marine refrigeration shop didn't seem to know anything about it.
krj

SSB noise
 

Once you check out the site I mentioned earlier (print it out) start at
the GPS wiring, where it's signal is being sent to whatever...
computer, VHS, SSB, etc. That's most likely where the problem is.

SSB noise
 

Keith wrote:
Once you check out the site I mentioned earlier (print it out) start at
the GPS wiring, where it's signal is being sent to whatever...
computer, VHS, SSB, etc. That's most likely where the problem is.

As I replied earlier, the problem is radiated noise from the Danfoss
BD50 compressor control module. I have turn every electrical item on the
boat on and off individually to determine which, if any, generate noise,
either via the DC wiring or radiated. None cause a problem except the
compressor module. Glenn Ashmore provided the part numbers of shielded
control modules. I believe that when I finally find a place to purchase
one, my problem will be solved.
krj

SSB noise
 

krj wrote:
I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.
krj

Hi KRJ,
Yes indeed a Danfoss compressor is a heck of a source of noise. The
Gordon West article talks about putting aluminum foil around the
compressor to make a sort of a faraday cage to mute this noise...been
there, done that, bought the tee shirt and it didn't work. The only
solution I've found in 9 years of cruising is to turn the offending
appliance to the OFF position!

There are other sources of noise that can interfere with SSB reception
on a boat. I've recorded a bunch of them on the CD ROM that comes with
my book, Marine SSB Radio for Idi-Yachts.
See http://www.idiyachts.com for more info

Inverters, pumps, fans, shore power and the like can mess up the radio
reception as well.
Happy Holidaze!
Capt Marti

SSB noise
 

Capt Marti wrote:
krj wrote:
I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.
krj

Hi KRJ,
Yes indeed a Danfoss compressor is a heck of a source of noise. The
Gordon West article talks about putting aluminum foil around the
compressor to make a sort of a faraday cage to mute this noise...been
there, done that, bought the tee shirt and it didn't work. The only
solution I've found in 9 years of cruising is to turn the offending
appliance to the OFF position!

There are other sources of noise that can interfere with SSB reception
on a boat. I've recorded a bunch of them on the CD ROM that comes with
my book, Marine SSB Radio for Idi-Yachts.
See http://www.idiyachts.com for more info

Inverters, pumps, fans, shore power and the like can mess up the radio
reception as well.
Happy Holidaze!
Capt Marti

Actually, after several emails and info from Glenn Ashmore, I found that
Danfoss makes a shielded version of the controller with ferrite isolated
leads that will eliminate the noise. Gordon West was full of bs in the
article about the noise eminating from the digital thermostat. I
disconnected it and put in a manual one, the noise was still there.
krj

SSB noise
 

krj wrote:

Actually, after several emails and info from Glenn Ashmore, I found that
Danfoss makes a shielded version of the controller with ferrite isolated
leads that will eliminate the noise. Gordon West was full of bs in the
article about the noise eminating from the digital thermostat. I
disconnected it and put in a manual one, the noise was still there.
krj

Did Gordon West identify the digital thermostat as the source?

In my reading of his article and in his recommendations, which I
summarised earlier in this thread, he focuses on the controller and the
compressor - all his recommended actions are about shielding the
controller and placing ferrite chokes on its connecting wires.

And that's exactly what you get if you manage to find the shielded
Danfoss controller (which seems quite hard to find - I've seen it
listed in catalogs but never seen a live one.

Cheers

Bil

SSB noise
 

In article ,
krj wrote:

Capt Marti wrote:
krj wrote:
I just finished installing an SSB on my boat. When I turn on my freezer
I get noise on the radio that sounds like morse code. The freezer has a
Danfoss BD50 compressor with a digital thermostat. Has anyone else had
this problem. I think I remember Gordon West writing about this problem
in one of the sailing mags. but can't remember which one or when.
krj

Hi KRJ,
Yes indeed a Danfoss compressor is a heck of a source of noise. The
Gordon West article talks about putting aluminum foil around the
compressor to make a sort of a faraday cage to mute this noise...been
there, done that, bought the tee shirt and it didn't work. The only
solution I've found in 9 years of cruising is to turn the offending
appliance to the OFF position!

There are other sources of noise that can interfere with SSB reception
on a boat. I've recorded a bunch of them on the CD ROM that comes with
my book, Marine SSB Radio for Idi-Yachts.
See http://www.idiyachts.com for more info

Inverters, pumps, fans, shore power and the like can mess up the radio
reception as well.
Happy Holidaze!
Capt Marti

Actually, after several emails and info from Glenn Ashmore, I found that
Danfoss makes a shielded version of the controller with ferrite isolated
leads that will eliminate the noise. Gordon West was full of bs in the
article about the noise eminating from the digital thermostat. I
disconnected it and put in a manual one, the noise was still there.
krj

I suspect you will find that, Gordie West is fULL of BS, on a lot of
things.......