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

I got a response from a friend on the Bristol Channel Cutter list who uses a
DC to DC converter for his laptop. Sort of a Gordion Knot-cutting solution -
why try to fix an inherently noisy brick if a quieter purpose-made device is
obtainable. His was made by a "Ham in Florida" and is very quiet - but he
can't find the address of the guy who makes them. Since my Vaio's brick
output is 19.5V I guess a stepup tranformer has to be part of any 12V input
converter. Any problems with this approach and any thoughts about who makes
one?
Scott


"Meindert Sprang" wrote in message
...
"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

http://lindelectronics.com/cgi-bin/store/shop.cgi/!ORDERID!/aaa/x/dbx_gen_aaa_mfgs/



"scott" jsodellatgmail.com wrote in message
...
I got a response from a friend on the Bristol Channel Cutter list who uses
a DC to DC converter for his laptop. Sort of a Gordion Knot-cutting
solution - why try to fix an inherently noisy brick if a quieter
purpose-made device is obtainable. His was made by a "Ham in Florida" and
is very quiet - but he can't find the address of the guy who makes them.
Since my Vaio's brick output is 19.5V I guess a stepup tranformer has to be
part of any 12V input converter. Any problems with this approach and any
thoughts about who makes one?
Scott


"Meindert Sprang" wrote in message
...
"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

I have a 12v to 19v car laptop adaptor,(DC to DC) which was shop bought
for Eur40, (made in China). It turns ship's 12volt supply into a
selectable voltage to suit a range of laptops. As it is onboard and I
am not, I can't give precise detail now, but do a Google search for
"Car laptop adaptor" and it will link to suppliers.
This is more efficient as it saves energy by not having to use an
inverter to go 12v to 115/230v to power the laptop's power brick. A
win-win situation as it saves the inverter losses in addition to
removal of another noise souce
Noel

I have a 12v to 19v car laptop adaptor,(DC to DC) which was shop bought
for Eur40, (made in China). It turns ship's 12volt supply into a
selectable voltage to suit a range of laptops. As it is onboard and I
am not, I can't give precise detail now, but do a Google search for
"Car laptop adaptor" and it will link to suppliers.
This is more efficient as it saves energy by not having to use an
inverter to go 12v to 115/230v to power the laptop's power brick. A
win-win situation as it saves the inverter losses in addition to
removal of another noise souce.
Nol

Yes, this is what I finally decided to do - seems by far the most elegant
solution (though I did appreciate Lynn Coffelt's advice to try soaking the
AC-DC brick in sea water for 72 hours). I've ordered a DC to DC airplane
and automobile converter from Linde afdter following the link previously
suggested by "Johnhh"
http://lindelectronics.com/cgi-bin/store/shop.cgi/!ORDERID!/aaa/x/dbx_gen_aaa_mfgs/.
Not cheap but said to have good RF filtering to comply with airplane
regulations. Hope it works as advertised and will report back after I get
and try it.
Thanks.
Scott


"nollaigoc" wrote in message
oups.com...
I have a 12v to 19v car laptop adaptor,(DC to DC) which was shop bought
for Eur40, (made in China). It turns ship's 12volt supply into a
selectable voltage to suit a range of laptops. As it is onboard and I
am not, I can't give precise detail now, but do a Google search for
"Car laptop adaptor" and it will link to suppliers.
This is more efficient as it saves energy by not having to use an
inverter to go 12v to 115/230v to power the laptop's power brick. A
win-win situation as it saves the inverter losses in addition to
removal of another noise souce.
Nol