I've just installed an ICOM 802 in my boat and today found that the only way
to get clean noise-free weatherfax reception on my Sony VAIO laptop is to
disconnect the "power brick" and run the laptop on batteries alone. There
are some other interference sources, especially the radar, but the laptop is
the most inconvenient problem at the moment. Any suggestions as to how to
reduce or eliminate RF interference from a VAIO power brick?
TIA,

Scott
jsodellatgmail.com

"scott" jsodellatgmail.com wrote in message
...
I've just installed an ICOM 802 in my boat and today found that the only
way
to get clean noise-free weatherfax reception on my Sony VAIO laptop is to
disconnect the "power brick" and run the laptop on batteries alone.
There
are some other interference sources, especially the radar, but the laptop
is
the most inconvenient problem at the moment. Any suggestions as to how to
reduce or eliminate RF interference from a VAIO power brick?

RF noise on HF frequencies need an antenna to be radiated and the antennae
in this case are the power cords to and from the power brick. The power
brick itself has to small dimensions to radiate sufficiently on HF. So all
you need is to block the RF through the power cords. This can be done by
running the cords through ferrite ring cores. Run each cord through a ring
core, 10 loops or so. Ferrite clamps are mostly not so effective at HF, but
more at VHF. You could try and find a radio ham in your neighborhood, they
deal with these issues more often.

Meindert

Quoting "Meindert Sprang"SNIP
Any suggestions as to how to
reduce or eliminate RF interference from a VAIO power brick?

RF noise on HF frequencies need an antenna to be radiated and the antennae
in this case are the power cords to and from the power brick. The power
brick itself has to small dimensions to radiate sufficiently on HF. So all
you need is to block the RF through the power cords. This can be done by
running the cords through ferrite ring cores. Run each cord through a ring
core, 10 loops or so. Ferrite clamps are mostly not so effective at HF,
but
more at VHF. You could try and find a radio ham in your neighborhood, they
deal with these issues more often.

Meindert


Thanks, that's helpful. I got another suggestion off-list that shielding the
brick in a grounded steel box might help but given the brick's small size I
guess I will start with your ferrite sugesstion. Any suggestions on the best
source for apppropriate ferrite ring cores? In browsing online cataologues
this HF radio novice has found a bewildering variety of ferrite devices and
materials. I agree that my next task is to find a local radio ham and get
some hands-on help.
Thanks, Scott

"scott" jsodellatgmail.com wrote in message
...
Thanks, that's helpful.

I forgot to mention that the ferrites are to be placed on the power brick
side of each cable. Another one on the laptop side would surpress any
interference out of the laptop's internal switchers.

I got another suggestion off-list that shielding the
brick in a grounded steel box might help but given the brick's small size
I
guess I will start with your ferrite sugesstion.

Shielding the box only prevents interference from leaving the box by
radiation, and this will, given the small size of the box, only be in the
VHF-UHF range. HF interference is *always* transferred out of the box by
conduction through a cable. If you check the FCC/CE standards about
radiation limits, you will see that below 30MHz, only limits are given for
conducted emission.

Any suggestions on the best
source for apppropriate ferrite ring cores? In browsing online cataologues
this HF radio novice has found a bewildering variety of ferrite devices
and
materials. I agree that my next task is to find a local radio ham and get
some hands-on help.

Best bet indeed. Ferrites are specified for certain frequency ranges, so you
have to pick the right type here. I'm afraid I can't give you the exact type
from the top of my head, but 4C6 material comes to mind.

Regards,
Meindert

In article ,
"Meindert Sprang" wrote:

"scott" jsodellatgmail.com wrote in message
...
Thanks, that's helpful.

I forgot to mention that the ferrites are to be placed on the power brick
side of each cable. Another one on the laptop side would surpress any
interference out of the laptop's internal switchers.

I got another suggestion off-list that shielding the
brick in a grounded steel box might help but given the brick's small size
I
guess I will start with your ferrite sugesstion.

Shielding the box only prevents interference from leaving the box by
radiation, and this will, given the small size of the box, only be in the
VHF-UHF range. HF interference is *always* transferred out of the box by
conduction through a cable. If you check the FCC/CE standards about
radiation limits, you will see that below 30MHz, only limits are given for
conducted emission.

Any suggestions on the best
source for apppropriate ferrite ring cores? In browsing online cataologues
this HF radio novice has found a bewildering variety of ferrite devices
and
materials. I agree that my next task is to find a local radio ham and get
some hands-on help.

Best bet indeed. Ferrites are specified for certain frequency ranges, so you
have to pick the right type here. I'm afraid I can't give you the exact type
from the top of my head, but 4C6 material comes to mind.

Regards,
Meindert



All very good advice, BUT if one were to put the BRICK in a metal box,
and bring the wires in/out of the box, with Feedthru Capacitors of say
..01uf, all that hash would stay inside the box where it belongs.
Old School technology from way back......


Bruce in alaska
--
add a 2 before @

"Bruce in Alaska" wrote in message
...
All very good advice, BUT if one were to put the BRICK in a metal box,
and bring the wires in/out of the box, with Feedthru Capacitors of say
.01uf, all that hash would stay inside the box where it belongs.
Old School technology from way back......

Correct. But much harder to accomplish. And it has the disadvantage that the
power cord and the low voltage cord on the other side now form one large RF
antenna while using ferrites, the entire string of wire is broken into
smaller parts which inherently radiate less and also pick up less. It might
even be that in the first case you end up with a huge susceptibility for RF
from the SSB....
Shielding works, but it would involve shielding and grouding of every single
part in the loop. If that is not possible, it is best to break the loop at
as many places as possible.

Meindert

On Wed, 30 Nov 2005 00:13:55 -0500, "scott" jsodellatgmail.com
wrote:
I've just installed an ICOM 802 in my boat and today found that the only way
to get clean noise-free weatherfax reception on my Sony VAIO laptop is to
disconnect the "power brick" and run the laptop on batteries alone.

===================================

Are you running the power brick from a small inverter? If so, that is
more likely to be the noise source in my experience. Try running the
laptop on shore power while at a dock and see if you have the same
problem. If not, consider getting a better inverter. My Xantrex
Prosine generates very little RF noise compared to the small modified
sine wave units.

Responding to Wayne B.
Are you running the power brick from a small inverter?

No. At the moment It's hooked directly to shore power. In the past, while
underway I've used a small Radio Shack inverter and you are correct, this is
noisy enough to be a small problem with VHF. Have not tried it yet with the
SSB.

If so, that is
more likely to be the noise source in my experience. Try running the
laptop on shore power while at a dock and see if you have the same
problem. If not, consider getting a better inverter. My Xantrex
Prosine generates very little RF noise compared to the small modified
sine wave units.

I have a Xantrex 20A charger and yes, it is surprisingly quiet - can barely
detect the difference between on & off when listening to the SSB.

Scott

Hello Scott,

I assume you can hear the interference on the SSB's speaker when the
power brick is operating?

I also assume the laptop is connected to the SSB via a serial port (or
equivalently, to a TNC which in turn is connected to the SSB).

If yes to both, try disconnecting the laptop from the SSB/TNC to see if
you still hear the noise.

If the noise goes away, then Meindert's suggestion may help. You can
find clamp-on ferrites at Radio Shack. Use several turns per the
instructions. It would be best to install at least one on the serial
cable just before it connects to the SSB. Ideally, that would choke off
any RF on the cable.

If the noise is unaffected, the interference is probably being radiated.

If you are using the laptop's internal soundcard, then the audio lines
to and from the SSB should also have ferrite chokes.

Running the laptop on internal batteries should completely solve the
problem (while adding another, of course).

Good luck.

Chuck

scott wrote:
I've just installed an ICOM 802 in my boat and today found that the only way
to get clean noise-free weatherfax reception on my Sony VAIO laptop is to
disconnect the "power brick" and run the laptop on batteries alone. There
are some other interference sources, especially the radar, but the laptop is
the most inconvenient problem at the moment. Any suggestions as to how to
reduce or eliminate RF interference from a VAIO power brick?
TIA,

Scott
jsodellatgmail.com

Thanks for the good advice, comments below
"chuck" wrote in message
ink.net...
Hello Scott,

I assume you can hear the interference on the SSB's speaker when the power
brick is operating?

Yes, but only when it is plugged into the laptop

I also assume the laptop is connected to the SSB via a serial port (or
equivalently, to a TNC which in turn is connected to the SSB).

No, not from the tranceiver serial port, but directly from the ICOM 802's
control panel headphone jack to the laptop soundcard's mike input via a mono
audio cable.

If yes to both, try disconnecting the laptop from the SSB/TNC to see if
you still hear the noise.

The interference stops if I unplug the brick's lead to the laptop, even if
the brick is still plugged in to shoreside power.


If the noise goes away, then Meindert's suggestion may help. You can find
clamp-on ferrites at Radio Shack. Use several turns per the instructions.
It would be best to install at least one on the serial cable just before
it connects to the SSB. Ideally, that would choke off any RF on the cable.

If the noise is unaffected, the interference is probably being radiated.

If you are using the laptop's internal soundcard, then the audio lines to
and from the SSB should also have ferrite chokes.

I guess my next step is to try ferrites on the audio line. .



Running the laptop on internal batteries should completely solve the
problem (while adding another, of course).

Yes to both,
thanks

Scott

snip