I picked up some ferrite cores today and have been attaching them to
power cords, computer cables and my coaxial feedline. I can report a
definite reduction in noise. This is especially gratifying because
ferrite cores aren't too expensive.

Any advice about how to position these cores? Are they best placed
close to the electrical outlet or close to the computer, receiver or
device being used (or both)? Would appreciate your insights.

Thanks....Steve

wrote:

I picked up some ferrite cores today and have been attaching them to
power cords, computer cables and my coaxial feedline. I can report a
definite reduction in noise. This is especially gratifying because
ferrite cores aren't too expensive.

Any advice about how to position these cores? Are they best placed
close to the electrical outlet or close to the computer, receiver or
device being used (or both)? Would appreciate your insights.

Thanks....Steve

The first ones go on each end of your coax so RFI picked up on the shield isn't
radiated to your antenna, or brought back into the radio.

After that, if it's a device you think causes RFI, put them on the end of the
wire just as it comes out from the case first, to kill the RFI before the wire
can act like an antenna.

With things like incandescent lamps, if you're going to use one, put it near the
outlet so any RFI that snuck into your power line from something you didn't
track down yet doesn't get radiated by the power cord.

Think of the power cords as antennas for transmitting RFI. You want to choke it
off as close to the transmitter as possible.

Hope this helps.

Two or three weeks ago I saw a UK website about some new little ferrite
cores that are intended for use on cellphone earphones.They clip on the
cellphone earphone cords/wires.Suppose to help drain off cellphone
microwave energy.They might be handy for shortwave radios too.
cuhulin

wrote in message
...
Two or three weeks ago I saw a UK website about some new little ferrite
cores that are intended for use on cellphone earphones.They clip on the
cellphone earphone cords/wires.Suppose to help drain off cellphone
microwave energy.They might be handy for shortwave radios too.
cuhulin

The same cores that work at 800, 1.9GHz, 2.4 GHz will likely not be useful
at HF.
The whole idea that reducing RF on the earphone will be beneficial is
nonsense.
Right along the lines with the PC card antenna that fits under the cell
phone battery.
Dale W4OP

wrote:
I picked up some ferrite cores today and have been attaching them to
power cords, computer cables and my coaxial feedline. I can report a
definite reduction in noise. This is especially gratifying because
ferrite cores aren't too expensive.

Any advice about how to position these cores? Are they best placed
close to the electrical outlet or close to the computer, receiver or
device being used (or both)? Would appreciate your insights.

Thanks....Steve

I have found that I get the most noise reduction by
placing them as close to the RFI source as I can get.
I have found a very good source for ferrite "beads",
your local PC/TV repair shop. They often have lots of dead
VGA monitors, keyboards, mice etc. Almost all of these
have ferrite RFI supression one the cables. I wangled
permssion to cut the cables with the big blobs of plastic
off flush with the device. For the smaller items, mice,
keyboards, older hand held parallel scanners etc, I had
to agree to haul the "junk" off.
A little careful work with a sharp knife and you can
extract the ferrite beads. They, for th emost part,
aren't the type that snap togather, but I am willing to
replace a few connectors to get some quite.
Lots of RFI supresion for cheap.
Th efew snap apart feritte beads I got I used for
keyboards, my VGA monitor and other hard to replace
connectors.
I found that palcing several (10) on the coax that
carries my SW RF in I knocked the last RFI from the PC
down to "yea it's there, but it isn't a problem".
Terry

wrote in news:1107550345.029863.64640
@c13g2000cwb.googlegroups.com:

I picked up some ferrite cores today and have been attaching them to
power cords, computer cables and my coaxial feedline. I can report a
definite reduction in noise. This is especially gratifying because
ferrite cores aren't too expensive.

Any advice about how to position these cores? Are they best placed
close to the electrical outlet or close to the computer, receiver or
device being used (or both)? Would appreciate your insights.

Thanks....Steve



Where is a good place to get these in quantity, and is there any type of
choke that works better when you're dealing with shortwave listening?
Radio shack charges $6 each.

I see some less expensive ones at www.partsexpress.com.

Steve

"Dale Parfitt" wrote in
news:dXTMd.4364$uc.1179@trnddc04:


wrote in message
...
Two or three weeks ago I saw a UK website about some new little
ferrite cores that are intended for use on cellphone earphones.They
clip on the cellphone earphone cords/wires.Suppose to help drain off
cellphone microwave energy.They might be handy for shortwave radios
too. cuhulin

The same cores that work at 800, 1.9GHz, 2.4 GHz will likely not be
useful at HF.
The whole idea that reducing RF on the earphone will be beneficial is
nonsense.
Right along the lines with the PC card antenna that fits under the
cell phone battery.
Dale W4OP




I don't think the ferrite cores for cell phone headsets are for improving
reception--they're for reducing your chances of getting brain cancer. If
they make a difference in this regard, who knows...

wrote in news:1107574579.349714.195570
@g14g2000cwa.googlegroups.com:

I see some less expensive ones at www.partsexpress.com.

Steve



Are these suitable for use on AC cords and on the ends of coax cables?

http://www.partsexpress.com/pe/showd...number=110-450
http://www.partsexpress.com/pe/showd...number=110-452
http://www.partsexpress.com/pe/showd...number=110-454

"Conan Ford" wrote in message
3.159...
wrote in news:1107574579.349714.195570
@g14g2000cwa.googlegroups.com:


Are these suitable for use on AC cords and on the ends of coax
cables?


Looks like a good price, the 110-450 looks just like the ones Radio Shack
wants about 7 or 8 bucks a pair for and the same ones I purchased from Radio
Shack
5 or 6 years ago at three for about $5.00. Yes they do work, I have them on
both ends of all the cables in and out of my RX320 and computer. On small
audio cables I looped through them twice. RM~

PS, Digikey has good prices on them also but a tad higher than 95 cents ea.