Thanks for reading this message.
Setup: Catamaran 45'
ICOM M802 with AT140 tuner, professionally installed, sidestay ant
portside
Battery Charger/Inverter Mastervolt Dakar Sinus Combi, located in engine
room s/board side.

My problem, if the Battery charger/Inverter is on, which it normaly is a
carrier every 20khz (+ -) with a 60hz humm is audible over the whole HF
spectrum. Quite strong so that weak stations are not readable. The noise
is picked up via the arial not thru the DC supply. If I disconnect the ant
the noise is gone. But just having the ant tuner connected with no ant,
the noise is audible.
I am looking fwd to some ideas how to get rid of the interference
thanks and rgds
Wern

"Wern" wrote in
news:38fdceedabfe8e06be83e928337c76a8
@localhost.talkaboutelectronicequipm
ent.com:

Thanks for reading this message.
Setup: Catamaran 45'
ICOM M802 with AT140 tuner, professionally installed, sidestay
ant
portside
Battery Charger/Inverter Mastervolt Dakar Sinus Combi, located
in
engine room s/board side.

My problem, if the Battery charger/Inverter is on, which it
normaly is
a carrier every 20khz (+ -) with a 60hz humm is audible over
the whole
HF spectrum. Quite strong so that weak stations are not
readable. The
noise is picked up via the arial not thru the DC supply. If I
disconnect the ant the noise is gone. But just having the ant
tuner
connected with no ant, the noise is audible.
I am looking fwd to some ideas how to get rid of the
interference
thanks and rgds
Wern



Welcome to the club! EVERY boat I work on has RF noise coming
from:
A) the fancy electronic battery chargers
B) the fancy electronic reefers
C) the damned UNBALANCED, unshielded NMEA cables because the lazy
manufacturers tie (-) to ground, not keep it balanced.
D) electronic lighting (flourescents, some fancy LEDs with
dimmers, AC dimmers at the dock)
E) computers running aboard and the stuff that supports them,
including the computer's electronic power supply.
They all generate wide spectrum noise across HF.

At the dock, that awful noise is the crap electrical system, all
corroded up, feeding the dock. Some docks you can't use HF at
all!

The noise is so bad you just have to shut them down to use SSB.
You'll never shield it enough to stop it.

The cure for your battery charger problem is to go back to the
old non-electronic battery charger that produces no noise, except
for its big transformer humming against the steel cabinet. But,
the convenience of an automatic charger far outweighs the RF
noise. You can shut it down and talk on the radio on batteries.

Larry
--

In article "Wern" wrote:

Thanks for reading this message.
Setup: Catamaran 45'
ICOM M802 with AT140 tuner, professionally installed, sidestay ant
portside
Battery Charger/Inverter Mastervolt Dakar Sinus Combi, located in engine
room s/board side.

My problem, if the Battery charger/Inverter is on, which it normaly is a
carrier every 20khz (+ -) with a 60hz humm is audible over the whole HF
spectrum. Quite strong so that weak stations are not readable. The noise
is picked up via the arial not thru the DC supply. If I disconnect the ant
the noise is gone. But just having the ant tuner connected with no ant,
the noise is audible.
I am looking fwd to some ideas how to get rid of the interference
thanks and rgds
Wern


There are a FEW, tricks that you mght try, but the MAIN thing you will
find IS:

1. Any type of Switching Powersupply is going to produce wideband RF
noise across the MF/HF Radio Spectrum. Battery Chargers, Computer
Power Converters, DC Motor Brushes, a whole range of things cause
this problem.
2. Most ALL the OEM's of such equipment do NOT certify their stuff
for RF Noise output, and don't use this criteria as a design
parameter.
3. ReEngineering other peoples stuff is a PAIN in the Posterior.
4. Very few Mariners actually use MF/HF Radios in the Commercial
Services, these days, compared with Days gone bye, in the 60's
thru the 80's.
5. If you want to make it work, you have to either pay an OLD
Marine Radioman, a lot of money, to come fix it for you, or
learn to become an OLD Marine Radioman, and spent a little less
money to fix your problem. It is NOT, going to be cheap....

Bruce in alaska
--
add path before @

In article
outelectronicequipment
..com,
"Wern" wrote:

Thanks for reading this message.
Setup: Catamaran 45'
ICOM M802 with AT140 tuner, professionally installed, sidestay ant
portside
Battery Charger/Inverter Mastervolt Dakar Sinus Combi, located in engine
room s/board side.

My problem, if the Battery charger/Inverter is on, which it normaly is a
carrier every 20khz (+ -) with a 60hz humm is audible over the whole HF
spectrum. Quite strong so that weak stations are not readable. The noise
is picked up via the arial not thru the DC supply. If I disconnect the ant
the noise is gone. But just having the ant tuner connected with no ant,
the noise is audible.
I am looking fwd to some ideas how to get rid of the interference
thanks and rgds
Wern

You have to tackle this problem at the source - the inverter.

Either change to a model that properly isolates its internal switching
noise successfully, or a model that limits the noise by switching slowly
etc. As a last resort you'd use filters on inputs and outputs, assuming
the case is properly shielded.

You need someone with experience in HF and appropriate measuring
equipment - or get an inververter that is specified with respect to
emanated electrical noise.

HTH

Marc

--
remove bye and from mercial to get valid e-mail
http://www.heusser.com

"Wern" wrote in message
lkaboutelectronicequipment.com...
Thanks for reading this message.
Setup: Catamaran 45'
ICOM M802 with AT140 tuner, professionally installed, sidestay ant
portside
Battery Charger/Inverter Mastervolt Dakar Sinus Combi, located in engine
room s/board side.

My problem, if the Battery charger/Inverter is on, which it normaly is a
carrier every 20khz (+ -) with a 60hz humm is audible over the whole HF
spectrum. Quite strong so that weak stations are not readable. The noise
is picked up via the arial not thru the DC supply. If I disconnect the ant
the noise is gone. But just having the ant tuner connected with no ant,
the noise is audible.
I am looking fwd to some ideas how to get rid of the interference
thanks and rgds
Wern


If your inverter is a modified sine wave, this can make things pretty bad. I
think a pure sine wave will help alot.

I notice the issue when listening to long wave 198 for the shipping
forecast - even the GPS interferes with a ticking every second - as other
posts suggest, I will see about getting the NMEA balanced but do I just
leave the screen disconnected? any help gratefully received. I am using pro
microphone cable for sending nmea to the autopilot but what should I do with
the screen?


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