AMIR,

Besides adding / better Grounding in the Shack and at the Antenna.

ABOUT - RF Noise (RFI/EMF) and Ferrite Chokes
plus More Reading . . .
http://groups.yahoo.com/group/Shortw...a/message/6072

1. Try a few of the Snap-On Ferrite Cores "Chokes"
at both ends of the Coax Cable Feed-in-Line.

2. Try a Snap-On Feerite Cores "Chokes" on each short Coax
'patch' Cables going from one piece of equipment to the other.

FERRITE "CHOKE" CORE :
Snap-Together {Snap-On} Ferrite "Choke" Core for RFI
RadioShack Catalog # 273-105
http://www.radioshack.com/product/in...tId=2103222&cp
http://www.universal-radio.com/catalog/misc/1778.html
http://www.surplussales.com/FerSplit/FerSplit-1.html


THE MORE READING LIST :

Shortwave Hum
http://home.computer.net/~pritch/shortwav.htm

eHam.Net : Forum : RFI : Ferrite Cores
http://www.eham.net/forums/RFI/952

Radio Frequency Interference (RFI) Notes
- by M.D.Lowell, N1LO October, 1998
http://www.hamuniverse.com/rfi.html
http://www.harfordemcomm.org/files/rfi_tips_tricks.pdf

RF Feedback (applies to the migration of noise
from the Shack to the Antenna and back again)
http://www.frn.net/special/prsg/rffdback.html

RFI and You - by Jack Althouse, K6NY
http://www.wr6wr.com/newSite/article...ndyou0598.html

Noise, Grounding, and other swear words - by NX7U
http://members.cox.net/nx7u/mobile/noise.htm

Dealing with Computer generated RFI/EMI
- by Daniel Wee [9V1ZV]
http://www.repairfaq.org/REPAIR/F_CompRFI.html
http://www.arrl.org/tis/info/rficomp.html
http://tinyurl.com/86u5x

Ferrite on Reducing RFI - by W4AN
http://www.qth.com/ka9fox/Ferrite-on-Reducing-RFI.htm

The Proper Split Beads to Suppress RFI [Happy Suppressing!]
- by Alan Applegate [KØBG]
http://www.eham.net/articles/7596

Telephone RFI Filter Instructions
http://www.somis.org/T-RFI.html
Yes RFI and your Telephone Lines.

RFI/EMF Supplies - Ready Made or Build Your Own
http://www.qsradio.com/HFAntennas.htm
Take a look at the two Coax Cable Feed-in-Line devices:
* Snap-On Ferrite Bead = Mix #43
1-1/8" long. Fits RG-8, RG-213, etc
* Slide-Thru Ferrite Bead = Mix #43
1-1/8" long. Fits RG-58, RG-8X, etc
http://buxcomm.com/toroids_RFI.htm
http://www.g-mag.com/Products/emi%20filters.htm

OOPS ! - WHEN NOT TO USE ONE : [ A NO NO ! ]
- - - Snap-On Ferrite Choke hurts Shielded Loop
http://www.radiobanter.com/showthread.php?t=41


hope this helps - iane ~ RHF
.
.
.. .
= = = In ,
= = = "amir_segal2001" amir@s... wrote:

Hello,

Last night I started an RF Noise thread on the R75 groups,
but I think this is a more suitable forum. So here goes...

We all suffer from some RF noise killing us on listening to
our great radios. I know when I turn on my plasma tv in my
bedroom - forget about listening to anything. When I have
my light dimmer on - forget about listening. I am sure other
devices around my house kill me too that I am not even aware of.

I am trying to understand the issue and any way to rectify it.

I am using an AOR SA7000 roof-mounted antenna with coax from
it to the edge of the roof, drapes down to my bedroom window,
through the screen, around the room and into the receiver on
my nightstand. The SA7000 coax is RJ (or RG?) 58 with 50 Ohm
impendence which matches my R75 and AOR 7030 perfectly.

1) Is the noise from the TV (and dimmer and other) being picked
up by the portion of the COAX that is in the house or by the
antenna on the roof or both?

2) Will a balun help? What size or ratio? Configuration?

3) Can you find the sources with a device or other methods?

4) Can you find the frequency of the noise and will notching
with a filter help?

Someone suggested Eagle dimmer switch that has no noise.
Anything else that can be done?

At times when the TV is off and I turn everything off
(or sometimes even with certain items still on - not the tv,
though...) I get basically perfect, noise free reception.
But that's very rare.

Any help, advice or "lesson" will be appreciated!

Thanks,

Amir
.
.
Tous Sont Bienvenus ! - - - Groupe par Radio
d'auditeur d'onde courte pour des Antennes de SWL
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
Alle Sind Willkommen ! - - - Shortwave Radiozuhörer
Gruppe für SWL Antennen
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
Tutti Sono Benvenuti ! - - - Gruppo Radiofonico
dell'ascoltatore di onda corta per le Antenne di SWL
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
Todos São Bem-vindos ! - - - Grupo de Rádio
do ouvinte do Shortwave para Antenas de SWL
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
Ð’Ñ�е Ð*адушны ! - - - Группа оператора
на приеме коротковолнового диапазона
Radio дл� Aнтенн SWL
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
¡Todos Son Agradables! - - - Grupo de Radio del oyente
de la onda corta para las Antenas de SWL
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/
.
.
.. .

My favorite source for split cores:

http://www.mouser.com/catalog/623/660.pdf

Make sure you order material 31 whiich is effective at all SW
frequencies. Material 43 is not effective at lower frequencies.

Jim

In article ,
R.F. Collins wrote:

My favorite source for split cores:

http://www.mouser.com/catalog/623/660.pdf

Make sure you order material 31 whiich is effective at all SW
frequencies. Material 43 is not effective at lower frequencies.

The three point chart indicates that even the 31 material might not be
to good at 1 MHz. A lot of the pulse noise from electrical switching is
usually low frequency (in the KHz range) for the fundamental with
harmonics at higher frequencies. The low frequency pulse noise can
saturate radio front ends causing intermodulation products to show up
throughout the range (1 to 30 MHz) of a radio.

--
Telamon
Ventura, California

RFC and Telamon,

RF "Choke" Ferrite Material Info :
REF = http://www.mouser.com/catalog/623/660.pdf

From what I understand most of the pre-assembled Ferrite
Materials are Type # 43 to kill the lower frequency Noise
associated with power lines and electrical devices.
These lower frequency Noise Sources often have many
Harmonics across the High Frequency (Shortwave) Band.
They work well because they reduce the primary Noise
Source Frequency and most of higher frequency Harmonics.

If, however you feel that what you have is a Noise Source
that is not simply an Harmonic of a lower frequency primary
Noise Source. Then one of the other Ferrite Materials like
Types # 31 or # 61 may be the answer if in-fact the Noise
Source is being generated at some higher frequency.

Unless you have the test equipment to truly determine
which of the Noise Sources you have : Then this is simply
a process of trying One-at-a-Time as see what the results
are . . . . YMMV )


iane ~ RHF
http://groups.yahoo.com/group/Shortw...a/message/6093