[RFI] Common Mode RFI

Germino mgermino@inreach.com
Wed, 4 Dec 2002 17:59:48 -0800

> 1.  Is it likely that common mode RF flowing on the outside of coaxial
> cable would radiate into domestic telephone systems and computer modems,
> causing RFI?  How would one determine if this is the case (without buying
> common mode choke, first, and experimenting)?

I built a RF tester that checks for RF on cables.  It uses a split bead in a
plastic case that opens and snaps shut.  You put your cable across the bead
and close it   A one turn transformer is made by having a wire go across the
bead and into the box where I use germanium diodes to rectify the RF for the
meter.  QST has had a couple of construction projects about this type of
tester.  It only gives a relative reading, but it is very useful.

I think Palomar has a tester like what I am talking about.

73, AD6AA